back to article 10 PRINT "ZX81 at 37" 20 GOTO 10

The ZX81 was launched 37 years ago this week as a £49.95 kit (£69.95 assembled) and introduced an entire generation to the joys of computing, fights over the family television and prodigious use of sticky tape. Intended as a successor to the ZX80 (£79.95 as a kit and £99.95 with all the soldering taken care of-ish), the ZX81 …

  1. Lotaresco

    I remember...

    Writing a lunar landing game in Z80 Assembler then lovingly hand-coding it in hex. I worked hard to give it real-moon physics and "realistic" thrusters that displayed flashing '<' or '>' and '=" alternately to give the effect of 'flame' the sky was peppered with '.' and '*' and some of them twinkled in a completely non realistic manner.

    I loved it, friends hated it, but then having declared their hate would spend hours trying to land it before the "realistic" and almost inevitable crash happened.

    1. CrazyOldCatMan Silver badge

      Re: I remember...

      Writing a lunar landing game in Z80 Assembler then lovingly hand-coding it in hex

      We did something somewhat similar on the Nascom-1 that we had.

      Then, one day, we bought a ROM that contained Super Tiny Basic. No more hand-assembly!

      Sadly, it was very definately tiny and basic. But not so super.

      1. hplasm

        Re: I remember...

        I printed out the ROM listing for the Nascom 1 at college*. Took a whole *roll* of printer paper.

        I was impressed by the company 'Microsoft' that wrote it, then.

        * Also ripped of an eprom copy, intending to use it on my homebrewed Z80. heh heh.

      2. John Brown (no body) Silver badge

        Re: I remember...

        "Sadly, it was very definately tiny and basic. But not so super."

        The clue is in the name. Super Tiny (very, very small), not Super BASIC (very very good):-)

    2. Oh Homer

      Programming vs Hacking

      I remember being far more excited about PEEK and POKE than PRINT and GOTO. :)

      Actually, that's probably a serious point. Back then we were not only encouraged to program for ourselves, but we were also actively encouraged to "hack", which in my experience leads to far greater understanding of computing in general than just following textbook procedures.

      Not that I have an objection to software engineering. All Hail engineering principles! But that's only half the story. To understand how to fix things, you first need to understand how they break.

      1. Simon Harris

        Re: Programming vs Hacking

        Back then we were not only encouraged to program for ourselves, but we were also actively encouraged to "hack"

        One difference back then were that it was possible for a person to know exactly what every chip in the computer did - ok, some like the ZX81 and BBC Micro put stuff in custom logic arrays, but at least the BBC logic arrays were well documented. I don't know how good the ZX81 manuals were for that.

        Another difference was the DIL package. Back before surface mount became common, and 0.1" was the standard pitch for things us mortals had a good chance of being able to modify the motherboard without destroying it. And back when the highest frequency you were likely to see on a computer was 4MHz you could get away with a lot of circuit hackery before RF became a problem.

        1. geekbrit

          Re: Programming vs Hacking

          One of my favorite memories of my Nascom 2 - spending a couple of hours staring at the circuit diagrams (supplied with the kit) then realizing I could route a higher frequency clock through a spare DIP switch into the cassette UART... giving me screamin' fast 4096 baud program saves & loads! Just think... a whole 400 characters per second!

          1. Simon Harris

            Re: Programming vs Hacking "4096 baud"

            I think you'd need to do more than just change the UART baud rate.

            Wouldn't you also have to change the CUTS modulation frequency generator (it normally generated 1200/2400Hz, and I believe in the Nascom 2 was generated by dividing down a 500kHz clock using CMOS counters), or the phase would keep shifting and you wouldn't get a complete cycle for each bit?

            You'd need a 4096/8192Hz pair of signals - for comparison the MSX's 2400 baud doubled the CUTS modulation tones to 2400/4800Hz. I had an Oric-1 for a while which had a 2400 baud option, but I could never get it to work reliably. Well done if your 4096 baud worked!

  2. King Jack

    Gateway Drug

    I was too poor to afford one but my neighbour had one. I spent many hours typing away at the keyboard playing adventure games. When I got stuck I began reading the code to get the answers which proved more fun than the game itself. I mastered the 'Ram pack Wobble' which on reflection was a good thing. When the machine crashed, you had to re-input everything again. That was good practice and burned the language into your brain. They (thankfully) don't make 'em like that any more.

    1. SwizzleStick

      Re: Gateway Drug

      I had a metal bracket on to "secure" my ram pack and the fekker still wobbled from time to time.

      1. werdsmith Silver badge

        Re: Gateway Drug

        I reconditioned mine. Replaced the UHF RF TV modulator, and fitted an adapter to read SD cards. Every software title ever published for it fits on a single card. Very sentimental about it, I still remember the feeling of seeing it work for the first time, and as basic as it was - back then it was pure science fiction.

      2. Lotaresco

        Re: Gateway Drug

        "I had a metal bracket on to "secure" my ram pack "

        I had a ribbon cable with a socket at one end and an edge connector at the other. that meant that I could use the RAM pack and any wobbling of the ZX-81 didn't cause any problems. The sockets and edge connectors were available at Maplin.

        1. Little Mouse

          Re: Gateway Drug

          I had the whole unit sat on a metal sheet with the ram pack wedged tight with a piece of garden hose. It acted as a massive heat-sink and cured the wobble - Worked a treat. The design was from one of the many magazines - can't remember which one though.

          And if you needed to copy games:


          RAND USR 836

        2. David Glasgow

          Re: Gateway Drug

          Ahhhh. Maplin. :((

      3. big_D Silver badge

        Re: Gateway Drug

        I had a Bug Byte 16K RAM Pack and I built a base for the ZX81, the Bug Byte and a Kayde keyboard (real keys, woohoo!!!).

        It stuck everything firmly on the base and it fell off my desk once and I didn't get a RAM pack wobble!

        I had a dodgy extension lead, which could send a spike that would "break" a running program, even a machine code one with, which had disabled the break key press. This allowed me to them list the machine code and I could go in and, for example, change the shape of the space ship in Defendr (not a misspelling), which in turn would make it invulnerable to crashing into anything!

        3D Monster Maze was my first experience of 3D gaming and was, for its time, amazing, considering the 32x24 display!

        1. Missing Semicolon Silver badge

          Re: Gateway Drug

          +1 for 3D Monster maze!

          1. Anonymous Coward
            Anonymous Coward

            Re: Gateway Drug

            Don't forget 3D Defender!

      4. Jedit Silver badge

        Re: Gateway Drug

        The best RAM packs for the ZX81 were the dkTronics line. Instead of being a vertical box, they were shaped to fit the rear of the computer and came with a Velcro pad to secure the far end. Absolutely stable, and with larger surface area they ran cooler to boot.

        1. Peter Gathercole Silver badge

          Re: Gateway Drug

          I added an external keyboard using a Tandy membrane keyboard, suitably modified by scraping tracks and repainting with conductive paint. This was attached by a ribbon cable long enough that ZX81 and rampack was some distance from the keyboard. Never had a wobbly rampack crash after that.

          I also added a 7400 TTL on a small board in the Sinclair rampack to re-map the 1K of static memory to a usable memory address (which I used for small machine code assists to basic), and also added another 1K of static memory under the keyboard, attached to the ULA side of the bus isolation resistors. This allowed me to change the I register, which was used to hold the base address of the character generator table to point at an address in this RAM. This gave me a fully programmable character set! So my ZX81 was probably the only one with 18K of RAM!

          I also had a sound board from QuickSilver which provided 4 channel (3+white noise) sound using an AY-8910 sound generator added to the video signal using an external modulator. QuickSilver also produced a point addressable graphics board, but I think that worked by doing a similar trick to mine with the RAM, and writing all the characters out to the screen, and manipulating the pixels in each character cell. I believe that it came with some M/C routines in an additional ROM that allowed basic line draw commands.

          I had great fun getting it to produce harmonized music while drawing it on the screen at the same time. The only problem was that in 'slow' mode, the Basic was just a bit too slow to make it seamless.

          Although it looked a bit Heath-Robinson, it drew some interest in the computer club of which I was a member.

          1. John Brown (no body) Silver badge

            Re: Gateway Drug


            That was a very nice, user friendly sound chip in the day. It even had one (or two?) 8 bit user ports to control further device. I knocked up a few little circuits based on various "gunshot" type sound circuits to simulate a few drum sounds which left the "proper" audio channels for the music. I was well proud of that at the time!

        2. Danny 4

          Re: Gateway Drug

          dkTronics Rampack

          I had a Memotech 16K Rampack. Seems they used the same solution of velcroing a shaped metal-cased rampack to the back of the '81. Very stable and ran cool.

          Adding memory was the only way to make the ZX81 usable. Much like a the 16K vs 48K Spectrum.

          1. Jedit Silver badge

            "I had a Memotech 16K Rampack. Seems they used the same solution"

            Assuming I'm not misremembering the name after 35 years and we're not talking about the same peripheral: it's quite likely they used the same blueprint for the external shell, if not the same manufacturer.

      5. Pen-y-gors

        Re: Gateway Drug

        Ram Pack Wobble - bent coat hanger that clamped it into place.

        And don't forget the pack of frozen peas on top when it overheated and died.

        1. werdsmith Silver badge

          Re: Gateway Drug

          Two blobs of blu-tack fixed the wobble for me.

  3. Anonymous Coward
    Anonymous Coward

    One of our mainframe engineers bought one and asked me for some assistance in programming it. IIRC the 16K expansion pack used to get very hot.

    I had an Apple][ bought in 1979. For comparison with the ZX under-£100 prices - that had cost about £1800 with black&white video, 48KB of ram, and an Apple format floppy disk drive.

    To get down to the lower prices before the ZX you had to build your own - like the "Tangerine".

    About that time there was an explosion in PC magazines, exhibitions, and specialist shops. At one of the exhibitions we drooled over an Apple compatible Winchester hard disk of 10MB - priced at £2K (about £6K in 2018?).

    1. I ain't Spartacus Gold badge

      Yes, I remember those RAM packs - and they got very toasty warm. As well as being wobbly.

      I'm deeply insulted by the comment about only simple games. I remember playing a whole Harrier Jumpjet simulator. The graphics were amazing.

      1. PaulyV

        Computer exhibitions and shows - that takes me back. Being driven out by my Dad to hotels in places like Huddersfield or Grimsby, parking up and being directed to the conference suite. Desk after desk of Vic20's, Oric 1's and Dragon 32's were setup, each accompanied by a chap more than happy to talk about them at length. The BBC B's felt like the best built and eventually our primary school got one, whilst at home my parents splashed out god knows how much on a Dragon 32 which saw me through my youth.

        Never had a ZX81, but Dad did borrow an '80 for a week or two from one of his younger colleagues. I still recall tuning it in to the TV.

        1. Just Enough

          I have the afternoon I spent coding a borrowed ZX80 positively seared into my memory. Plugged into the TV. Tuning the TV to the right frequency. Lying on the carpet. The slightly burny smell of the components as they heated up. I started with a printout from somewhere, but soon went my own way, coding the animation of a graphic square bouncing across the screen, then "exploding" in the corner.

          I used a ZX81 not long after that, and of course a Spectrum. But no exaggeration to say that ZX80 was a defining moment in my life.

          1. mrdalliard
            Thumb Up


            Wonderful stuff. At the age of ten, my parents bought me a ZX-81 and I spent countless hours using it. My poor black and white TV got completely ruined in the end by "burn-in". Watching regular TV programmes got quite hard (as the picture got fuzzy) and images/listings that I left on the screen for too long ended up getting burnt in to regular viewing.

            I went from the ZX-81 to a Vic-20, which seemed a novel thing as it had sound, colour, a larger memory and a fairly reliable dedicated tape drive.

            I never looked back - I've been in IT most of my working life.

            1. I ain't Spartacus Gold badge

              Re: Burn-In

              I went from the ZX-81 to a Vic-20

              My mate's Dad had bought a ZX81 to play around with. But my older brothers pooled some birthday money to get a Vic-20 - so that was my first real experience of regular computing. Their next was an Amstrad CPC464. Happy days.

              The great thing about the Vic-20 was you could get some games in cartridge form and just plug them into the back, so you didn't have to wait for tape loading. Luxury!

            2. Anonymous Coward
              Anonymous Coward

              Re: Burn-In

              "I went from the ZX-81 to a Vic-20, which seemed a novel thing as it had sound, colour, a larger memory and a fairly reliable dedicated tape drive.

              I never looked back - I've been in IT most of my working life."

              That was me too.

              ZX81 -> Vic20 -> Spectrum -> Amiga -> PC -> Career in IT

              1. darklord

                Re: Burn-In

                for me

                ZX80>ZX81>BBC MOD B> COMMORE pet> AMSTRAD CPC464>SPRECTRUM> PC8088>PC8086>ATARI ST>286 onwards to a career in IT and there was an Osbourne in there somewhere.

              2. Anonymous Coward
                Anonymous Coward

                Re: Burn-In

                Similar path for me:

                ZX81 > Spectrum > Amstrad CPC6128 > IBM XT > Career in ICT

        2. Wayland

          The Dragon 32 was good for programming. The BASIC was fine and with an Assembler and text editor the 6809 was much nicer than Z80 or 6502. The only problem was no sound chip and poor video chip. If it had a couple of chips out of the BBC B it would have beaten it. Half the price at £200.

      2. CrazyOldCatMan Silver badge

        The graphics were amazing..

        .. for their time. I fired up a BBC B emulator recently to play some of the old games and got bored very quickly. Likewise with an Atari ST emulator.

        1. John Brown (no body) Silver badge

          ".. for their time. I fired up a BBC B emulator recently to play some of the old games and got bored very quickly. Likewise with an Atari ST emulator."

          Your imagination has died with age. Gameplay was often very, very good (lots of dross too!), but you really needed imagination to "see" what was going on. I wonder how many old farts here can "see" a cardboard box as a spaceship, a racing car, a train, a TARDIS etc and spend hours playing in it? I bet any 5 year old relatives you might have can do it.

          1. Dave K

            "Your imagination has died with age."

            Agreed. I'm a bit too young for the ZX81, I cut my teeth on the BBC. Games like Repton 3, Pac Man, Defender and of course Elite are still fun today, and really show just how much you can get out of these machines with some clever programming!

          2. Anonymous Coward
            Anonymous Coward

            Sam Fox Strip Poker on the Spectrum - 99% imagination.

    2. Ian Michael Gumby


      There was only one real computer magazine at that time (BYTE).

      Yeah, lots of toys... unfortunately we fried our boards when we were soldering in the PS cabling.

      (It was a cheap learning experience...)

      If we wanted a computer game... we had to write our own. Today.... kids just go online, or just buy it.

      How many people remember "Hello Sailor" ? ;-)

      Mine's the jacket with the HP RPN calculator in his pocket.

      1. Anonymous Coward
        Anonymous Coward

        Re: Memories...

        "Mine's the jacket with the HP RPN calculator in his pocket."

        Mine's the HP "Programmer" from 1978 that did octal and hex calculations - with binary shifts and XORs too.

      2. Peter Gathercole Silver badge

        Re: Memories... @IMG

        I'll see your HP RPN calculator (mine was an HP-45), and raise you (because of difficulty in fitting anything useful in the limited memory) a Sinclair Cambridge Programmable and a Commodore PR-100 (I also had a Texas TI-57 programmable at one time, but it went wrong after about 2 weeks, and I got my money back).

        I've forgotten all of the other calculators I've had across the years. I still have a TI-58 as an ultimate fallback, but I mainly use my 'phone now.

        Interestingly enough, in the past couple of weeks, I've had to remind a colleague about the fact that some calculators did arithmetic hierarchy (generally TI and possibly Rockwell), and some didn't (Sharp, Commodore/CBM, early Casio, and most cheap 4/5 function calculators). HP were pretty much a law unto themselves, using RPN.

        1. travellingman_us

          Re: Memories... @IMG

          I had the first Sinclair programmable calculator... that I bought with money from my first after school job!

          My math teacher & I had great fun writing programs to do all sorts of fun (but otherwise) boring things. It was so "revolutionary" it was actually allowed into my math higher exam -- calculators were allowed, and no-one had thought to restrict programmables yet!

          Helped me get a few, otherwise dodgy, points in some areas!

          1. Peter Gathercole Silver badge

            Re: Memories... @travellingman

            I'm really not sure how much of an asset the Cambridge Programmable would have been in an exam over a normal scientific calculator.

            It did not have any stored memory capability, so you would either take it in powered on, and risk the battery running out, or remember any program that you wanted to use, not that much of a problem, however, with only 32 (or was it 36) programmable steps.

            I did use a high-function Commadore SR4190R in a physics exam at university to do some linear regression that I could not remember the formula for. Worked out the results, then reverse-engineered the calculations to fit so I could present my 'workings'. Non-programmable scientific calculators were allowed, but I suppose it was cheating (a bit). I don't actually think that that exam added much to my overall degree.

        2. Mark 56

          Re: Memories... @IMG

          Mine's the one with the SwissMicros DM41L

        3. Ian Michael Gumby

          @Peter G. Re: Memories... @IMG

          If memory serves... mine had LEDs and I forget the model. We're going back over 40 yrs.

          Why play with a calculator when you had computers. ;-)

        4. AndyD 8-)&#8377;

          Re: Memories... @IMG

          "HP were pretty much a law unto themselves, using RPN."

          as did Sinclair's

    3. dmackenziephoto


      I built a Tangerine computer. I even had the rack mount for it and it's peripherals. Originally programmed via the hex keypad I graduated to a proper keyboard and the Basic ROM. Wonderful. I understood everything the 6502 CPU, and the serial chips could do. Loved it

  4. Geronimo!

    "Syntax error in line ..."

    "Magazines would publish reams of code to be laboriously entered before the user could spend a few happy hours playing "hunt the bug/misprint" and then be intensely disappointed with the results."

    1. Anonymous South African Coward Bronze badge

      Re: "Syntax error in line ..."

      Some magazines (later on) used to have a checksumming utility with which you input a line of code, then it gives you a checksum on completion of that line, which you then compared to the one in the magazine listing. If it compares, you continue on with the next line, if it doesn't, you re-input the entire line.

      Especially when having to input machine code stuff. Which tend to crash spectacularly should you get just one line wrong.

      1. Anonymous Coward
        Anonymous Coward

        Re: "Syntax error in line ..."

        "Especially when having to input machine code stuff. Which tend to crash spectacularly should you get just one line wrong."

        That has always been true of most computer languages. You can't lie to a computer.

        The alternative to the crash is the subtle bug that only shows up on certain occasions. It is not unusual for a bug after an enhancement to actually be a mistake that had been there for years.

        A new version of the established O/S was built for the latest model's prototype. There were two other mainframe models which were already being sold with the same O/S. After working OK on the prototype for several weeks - it suddenly started crashing.

        It turned out that an established code path did a bit test on totally the wrong address. The outcome of the test in the past had always sent it down a well worn path - and the alternative possibility had never been expected or tested.

        The crucial difference was that the name of the O/S file had now finally been changed - in only one character - to reflect the different mainframe model.

        The file name was also stored in memory after loading. That single character's address was coincidentally the one being mistakenly tested. The previous two mainframe models just happened to have a consistent setting of the bit in that character in the file name - the new name had changed the tested bit.

      2. Dave 126 Silver badge

        Re: "Syntax error in line ..."

        I didn't have a Spectrum, so instead read a book called How to Make Your Own Computer Game or similar, with lots of Basic code at the back. If the game you wanted to make was an adventure game. I spent a good few hours creating maps on square lined paper.

        I'm also nostalgic for airbrushed artwork - the go-to for near photorealistic artwork before computers got fast enough. Many a game box, electronics catalogue and Rick album cover would involve airbrushing.

        1. Paul Kinsler

          Re: a book called How to Make Your Own Computer Game

          hmm... didn't pdf's of those get stuck up on line last year or something?

        2. William Towle

          Re: "Syntax error in line ..."

          > I spent a good few hours creating maps on square lined paper.

          I found a pad of Speccy-specific "graphics paper" for making UDG/screen designs on, which I took to working on photocopies of - mainly because I couldn't find more, but I wouldn't have wanted to as it was a bit thin and disintegrated quickly if you ended up needing to take an eraser to it.

          Years of writing computer programs on regular squared paper in order to create something that resembled what would be on the screen later for easy checking has left me with handwriting that gets regular compliments on its readability, even when in my opinion it's a bit scrawled :)

          1. Hans Neeson-Bumpsadese Silver badge

            Re: "Syntax error in line ..."

            I found a pad of Speccy-specific "graphics paper" for making UDG/screen designs on

            Ah... the Print'n'Plotter Jotter - I had one of those. Useful but I found it did have a shortcoming in that the pixel-level templates didn't have a clear indication of the 8-byte blocks that the Spectrum allowed you to allocate colours to.

      3. JQW

        Re: "Syntax error in line ..."

        I can recall Your Computer magazine printing BASIC listings for their own checksum utilities for several platforms.

        Unfortunately at one point they cocked up this listing, so that after spending hours entering page after page of hex, the code would naturally crash as soon as you tried to run it, due to a subtle off-by-one error.

    2. druck Silver badge

      Re: "Syntax error in line ..."

      Magazine producers initially didn't have a clue how to reproduce listings on a page, they would use fonts where 1 & l and O and 0 were indistinguishable, add random line breaks, and often miss the end off a listing completely if it didn't fit the page layout. Fixing such issues after typing it all in was good experience for a career in sofrtware though.

  5. Anonymous South African Coward Bronze badge

    I haven't had a shufty at the ZX81 (or ZX80) but started with the 48k Speccy.

    Good memories of those happy days - including time spent typing in "The Eye of the Star Warrior" from a book (Spectrum Adventures : A giude to playing and writing Adventures by Tony Bridge and Roy Carnell).

    Roll on with the good memories of a bygone era!

    1. Dan 55 Silver badge

      Mine was a 16K Speccy which later had the memory expansion and then the Plus keyboard added.

      If you'd told people then that 40 years later you'd be expected to throw the whole lot away and buy a new one each time you wanted to upgrade, they'd have thought you were off your rocker.

      1. T-Bo


        Indeed - Apple told me that in 1985 when I first asked about upgrading my $2500.00 128 Mac to a 512, and I was floored. Though they did eventually get round to offering an upgrade (for $1000.00), by then I had bought a 2nd hand IBM XT clone with a CRT, a stack of software, and dot-matrix printer, all for the princely sum of $400.

        Had a blast with that thing, learning about expansion boards (anyone remember the CopyIIPC boards?), upformatting old full-height HDD's, adding a RTC chip (which the early XTs sadly lacked) ... I learned a ton off that little investment.

        I've never looked back, and have never purchased an Apple product since.

        1. 45RPM

          Re: Predators

          @T Bo

          In fairness, it wasn’t too expensive (a couple of hundred quid, IIRC, and three or four hours of work) to upgrade a 128k Mac to a 512k.

          I can’t remember the exact procedure, but I seem to remember that it was necessary to build a new multiplexer board to handle the memory addressing - and of course to you needed some (fairly basic - remember, the chips were all pin-through-hole) soldering skill to remove the chips and replace them with the new parts. Of course, prudent souls socketed the replacement parts so that fallback was easier.

          I didn’t attempt upgrading to 1MB in the same way - Apple changed the ROMs for the Mac Plus so the sensible course of action was a new logic board. In my case I got an Amateurstrad PC (and hated it), so replaced that with an Opus 386, a Dell 486 - and then a healthy mix of Macs and PCs ever since.

          My ZX81, on the other hand, had the wobbly RAM pack - and a third party keyboard which contrived, if anything, to be worse than the membrane original.

          Happy days. I often think that we’d be better off returning to those halcyon days of the C64, PC, Apple II, Mac, Speccy, ST, Amiga, Archie et al - and ditching the internet along with all the horrors it contains. We could spend hours waiting at local landmarks, in the rain, waiting to see if our mates would show up. Hours idly waiting for a taxi at the end of a night. Dangerous walks up the hard shoulder to an emergency phone because the Marina had broken down again. Sigh.

          Happy days.

      2. mrdalliard

        >>If you'd told people then that 40 years later you'd be expected to throw the whole lot away and buy a new one each time you wanted to upgrade, they'd have thought you were off your rocker.

        Bought any Apple kit recently?

  6. Lotaresco

    Where are we now?

    For the price that a ZX-81 cost at launch, I bought a "mini PC" last week. Today £99.95 gets you a N3450 1.1GHz quad core processor, 4GB of RAM, 32GB SSD and 4K graphics. Adjusted for inflation the ZX-81 would cost £482.03 today.

    1. big_D Silver badge

      Re: Where are we now?

      I remember my ZX81 cost me 6 months of weekend job money and my parents paid the rest...

    2. I am the liquor

      Re: Where are we now?

      Never mind 4K, the Spectrum had 6K graphics! Of course in those days, that meant something different.

  7. Anonymous Coward

    And now we can relive the nostalgia with the Vega+

    ...oh, wait...

    1. Anonymous Coward
      Anonymous Coward

      Re: And now we can relive the nostalgia with the Vega+

      To be fair they did quite accurately recreate one aspect of the 80s home micro boom: taking money for a product that doesn't exist.

  8. ForthIsNotDead
    Thumb Up

    The best thing about the ZX81...

    ...and the ZX Spectrum wasn't the hardware. It was the manual that came with them.

    In both cases, the manuals were absolutely excellent, perfectly pitched at the total beginner, whether young or old. Even as an 11 year old kid with no prior programming experience, and nobody available to go and ask, you could pick up everything you needed to know from those excellent manuals. By comparison, the Commodore manuals (along with their BASIC language) was quite poor. Later I ailso got an Atari 800XL, and the manual for that was frankly pathetic, being about 20 or 30 pages long. The Sinclair manuals were hundreds of pages.

    The combination of the quality of those manuals, and of course, the (relatively) affordable price of the hardware (£100 was a fair wedge back in 1981/82, especially with 3 million of Maggie's minions un-employed, as was my Dad) is what helped to foster a generation of back-bedroom programmers that still work in the industry today.

    And while I'm in a praising mood: Teachers. I remember my secondary school teachers at the time, 82, 83, 84, 85, being just as addicted to these new home computers as us kids. They facilitated after school computer clubs, scrounging TV sets from around the school, bringing in their own computers, encouraging us to being in our machines, demo the programs we had written, help to teach us new techniques, and even learn from us.

    When we weren't all playing games, that is :-)

    What marvellous, lovely teachers they were, and how lucky I was to have been born in 1970, at the perfect age to take advantage of the home-computer boom.

    Looking back at the early 80s Britain, there wasn't all that much to be cheerful about: Miners strike, Falklands war, 3 million on the dole, etc. especially for our parents, but for us kids that were in the right place at the right time, it was a golden age and I wouldn't swap it for anything.

    Oh, and the music was better ;-)

    Have a good day, all.

    1. Anonymous Coward
      Anonymous Coward

      Re: The best thing about the ZX81...

      "In both cases, the manuals were absolutely excellent, perfectly pitched at the total beginner, whether young or old."

      The 1978 Motorola 6800 evaluation kit was a board and a set of chips. You then had buy all the other components, solder the board, get a decent psu, and find a teletype for a console. You could buy extra chips to populate the maximum of 1KB.

      The manual was a large format tome about 3 inches (75mm) thick. It gave a beginners guide to programming the board in machine code. It also had lots of working examples of how to drive peripheral functions via the GPIO - instead of dedicated logic ICs. That was an eye-opener to our design engineers who had expected these new devices to be used as PCs - not as substitutes for TTL hardware.

      1. Phil O'Sophical Silver badge
        Thumb Up

        Re: The best thing about the ZX81...

        It also had lots of working examples of how to drive peripheral functions via the GPIO - instead of dedicated logic ICs.

        Ah yes, making correctly-sequenced traffic lights using Red, Yellow and Green LEDs - seemed so clever at the time, all programmed in hand-assembled hex.

    2. I ain't Spartacus Gold badge

      Re: The best thing about the ZX81...

      I got the Amstrad PCW8256 in the late 80s. It came with two spiral bound manuals, each an inch thick. One was just for Mallard Basic and how to code it. The other was a sort of general how to use the computer and the Locoscript word processing and (basic) spreadsheet software that also came with it. So it started you off with how to turn the thing on and reboot, then how to creat "start of day" discs so that it would boot into the software you needed with the right data/templates/setup - and also so you didn't wear out your original media. Then how to operate the software, and what other stuff you could do with it, and how to operate the printer.

      Amazingly good resources compared to what you get nowadays. And far superior to be able to look stuff up when something's going wrong - although nowadays you can fix so many problems by whipping out a tablet/phone and google an answer if your PC isn't cooperating.

      I'm told that I wasn't so respectful of this great material as a teenager. I remember fixing a family friend's in his office. He was desperate because he'd hit print on a document he hadn't saved. Oh noes! Something I'm lazy about now, but wouldn't have dared do then. It was a 37 page (why do I still remember that from nearly 30 years ago?) quote for a £100k job - that he really didn't want to have to re-type and re-calculate. He tells me I walked into the office, he gave me the manual to help me, and I chucked it into the bin and said something I probably thought was witty about that being useless.

      Ha! Teenagers! I remember reading the manual when I got mine, so maybe that was my teenaged self being an arrogant arse, rather than an ungrateful arse?

      1. CrazyOldCatMan Silver badge

        Re: The best thing about the ZX81...

        so maybe that was my teenaged self being an arrogant arse

        It's part of the design spec for that odd creature "the teenager". It's the ones that aren't that you have to worry about.

    3. David Nash

      Re: The best thing about the ZX81...

      Yes, I was an 11-year old kid and I learned to program in BASIC from the ZX80 manual which I read in bed. I had to wait for the actual computer until my dad had finished soldering the kit together. But when he did, it worked, and I knew what to do.

      The kits also came with circuit schematics, which for the ZX80 was a marvellous education, as it was all implemented in standard logic chips, nothing custom.

      The ZX81 replaced something like 21 chips with one big custom black box, not much you could learn from that!

      1. Anonymous Coward
        Anonymous Coward

        Re: The best thing about the ZX81...

        "I had to wait for the actual computer until my dad had finished soldering the kit together. But when he did, it worked, and I knew what to do."

        At an earlier technology cusp - circa 1961 - my father bought a kit for a 3 transistor MW radio. It didn't need soldering. No circuit board - it was assembled as a rats' nest of wires joined together with 8BA nuts and bolts. The typical household soldering iron in those days was a large chunk of pointed copper on the end of an iron rod - that was heated in the fire.

        When the radio was finished - it didn't work. Quoting the advert's slogan of "A child can do it" - it was given to me and I made it work. So started my lifelong addiction to electronics. The radio eventually was upgraded to a Class B pair of OC72 with a proper speaker for my bedside.

        My father's next attempt to get a portable transistor radio was one being sold by a shop cheaply - because they had a batch with damaged circuit boards. I managed to repair it. Throughout my teenage years I supplemented my pocket money by doing the repairs that shops classed as "uneconomical" eg dropped in bath; dropped from window; fell off a motorbike.

    4. John Brown (no body) Silver badge

      Re: The best thing about the ZX81...

      "By comparison, the Commodore manuals (along with their BASIC language) was quite poor. Later I ailso got an Atari 800XL, and the manual for that was frankly pathetic, being about 20 or 30 pages long. The Sinclair manuals were hundreds of pages."

      The BBC manual was also excellent. Most UK micros came with comprehensive manuals, sometimes even with the circuit diagram of the computer. US micros on the other hand seemed to be aimed more directly at a "consumer" who would buy software and only a very few dedicated users would buy the extra books and documentation to "do stuff" with them.

    5. Peter X

      Re: The best thing about the ZX81...

      The cover art for both, but (IMHO) the Spectrum in particular, was great as well.

      (google image search for "zx spectrum manual cover art")

      1. Dan 55 Silver badge

        Re: The best thing about the ZX81...

        The Spectrum's inspiration was Cloud City, but the ZX81's was Tron before Tron was released.

    6. ThomH

      Re: The best thing about the ZX81...

      A quote that has inexplicably stuck with me from the Spectrum's manual: "Functions are practically indistinguishable from sausage machines but there is a difference: they work on numbers and strings instead of meat."

      Just say that at your next job interview. Maybe skip the second clause for brevity.

    7. Anonymous Coward
      Anonymous Coward

      Re: The best thing about the ZX81...

      I also was at secondary school in the 80s, and sadly it was a fairly dismal experience (and of course unfortunately I didn’t realise quite how dismal at the time, as it was all that I knew).

      I grew up in a turgidly boring small town (bloated village would be a better description, lots of newish commuter houses, but absolutely no increase in the non-existent community facilities to match), and the teachers were on strike for almost all of my secondary schooling. So, no after school clubs, no school trips, and not even any street corners to hang out on. At least we did have a ZX Spectrum to try to stimulate our minds away from the otherwise soul-crushing ennui...

  9. Professor Clifton Shallot

    I had a ZX80. It may have been inferior to the ZX81 (and indeed every other computer I've ever touched) but it looked terrific - sleek and futuristic.

    The Cambrian Explosion of home computers round that time was really exciting - and while I appreciate that standardisation has allowed to get a lot of stuff done more easily, I do miss the wild diversity of that period.

    1. CrazyOldCatMan Silver badge

      while I appreciate that standardisation has allowed

      Anyone remember the MSX (I think) line of computers? Supposed to enable manufacturers to produce 'standard' home computers?

      No - me neither.

      1. Anonymous Coward
        Anonymous Coward

        Anyone remember the MSX (I think) line of computers?

        I do - I recall my friend Mark S had one. I started with a shared, second hand, zx81 (some relatives had upgraded), then got a BBC B, and eventually added a 6502 co-processor. The hours and hours of time spent programming largely pointless and uninteresting games, and then playing them!

      2. BinkyTheMagicPaperclip Silver badge

        I had (and still have) an MSX. Wasn't too bad a machine, plenty of RAM, not too difficult to expand. Decent keyboard and BASIC. Unfortunately it was never as popular as the alternatives, so it tended to get a number of Spectrum ports that didn't take advantage of the hardware.

        It also had quite a number of cartridges available for it, something that didn't really happen for many other home computers.

        I'll admit the Commodore 64 had better capabilities in some areas (scrolling, music). The MSX had more available memory as the graphics memory was not shared, and more colours were available than the '64 in its high resolution mode.

        1. YouStupidBoy

          Re: MSX

          I, too, still have my MSX up in the attic. It was my very first computer that I must have spent thousands of hours either playing or programming, or just waiting for the tape to load, making sure it was at the right volume setting for the title in question.

          That box of happiness gave me 5 years of happiness in my childhood. Was finally retired when the keyboard membrane gave out to such an extent that even reassigning keybinds with the "KEY=" command to rebind the function key(s) to either "C, B or L" so I could load games :)

          Next machine was a spectrum +2a, which did me another good 5 years, then in '94 or so a 286PC (no more tape loading, yay!), then a "proper" PC in '96 running a Cyrix-something-90.

          Now I wanna go back. Again....

    2. big_D Silver badge

      I really wanted a Cantab Jupiter Ace, the looks of a ZX80, but with Forth instead of BASIC... But I went with a Memotech MTX500 instead.

      Yes, I remember MSX. There was a long row of different MSX models one of the electronic stores in Crawley (Dixons?). Sony, Hitachi and a few others. Exotic designs, but they never took off. That was a Microsoft project, by the way.

  10. A Non e-mouse Silver badge

    Display Memory

    With displaying a screen consuming 793 bytes of precious, precious memory

    Actually the ZX81 was a bit cleverer than that. If it detected it only had 1K of RAM, it used a slightly different way to story the screen: It stored each line up to its newline. That way, short lines of text used less memory than long lines. I recall seeing a game that only used the top-left corner of the screen to save memory.

    1. deanb01

      Re: Display Memory

      It's also possible to fool the display routines into producing a pseudo high-resolution image.

      1. A Non e-mouse Silver badge

        @deanb01 Re: Display Memory

        It's also possible to fool the display routines into producing a pseudo high-resolution image.

        In the days of the 8-bit (and I think 16 bit) home computers, the hardware was simpler and usually well documented so you could perform all sorts of tricks way beyond what the manufacturer originally intended. That's why emulating a lot of this hardware is quite hard as you have to emulate the chips to a very precise level to allow those hacks to work. See this Ars Technica article about the difficulty of doing accurate emulation.

        1. big_D Silver badge

          Re: @deanb01 Display Memory

          My first day at college, we had to write a simple program to take a value and work out the minimum number of coins to give in change.

          We were using CBM Pets, which I had cut my teeth on in school. I finished the program in around 10 minutes (it was the first lesson of the year and they wanted to see what level of programming we were at) and there was still around an hour of the class left.

          Getting bored, I switched to machine code and drew a border around the screen, split it in two and used get instead of input to poll the keyboard and then display the value in 8x8 graphic matrices at the top of the screen and display small piles of "coins" at the bottom for the different denominations. The lecturer came round to see how we were doing and stared in amazement, saying, "wow, I didn't know you could do that with a computer!"

          Erm, I'm the one who is here to learn!!

          Once, I was visiting a customer and they took my boss and me out to lunch, back in the days where you could drink a few pints and still get back on site afterwards... I was a little addled and my boss had a meeting for another hour or so, so they sat me in a corner with an old HP 125 CP/M machine... To while away the time, I wrote a quick game of breakout. :-D

          1. John Brown (no body) Silver badge

            Re: @deanb01 Display Memory

            "The lecturer came round to see how we were doing and stared in amazement, saying, "wow, I didn't know you could do that with a computer!"

            Erm, I'm the one who is here to learn!!"

            And I bet he then went on to teach you all sort of things you didn't know. Just not 6502 assembly :-)

            I also had lectures like that. Years of mainframe and minicomputer experience, but little to none on microprocessors where you get the "bang the metal". Systems design, systems analysis, how do to do proper documentation and work in teams to produce stuff that not only works but can be looked at and understood/maintained later by new people. Sigh, you're right, the good old days do bring a strong sense of nostalgia. I guess that means DevOps are the new bedroom coders?

            1. big_D Silver badge

              Re: @deanb01 Display Memory

              I never really learned anything at college, I just went there for the qualifications. I cruised through the whole course to get an A.

              The second year, we learnt COBOL and I had taught myself enough over the summer, that I had finished the first semester assignment in the first week of "learning" COBOL...

  11. beaker_72

    Tape loading

    I remember going along to our after school computer club, run by enthusiastic parents who all brought in their ZX81s and Spectrums. After watching one parent plugging in an earpiece to listen to the tape loading noises and nodding knowledgeably, I decided never to go back as even at that tender age I could tell that the sky in my world was a different colour from theirs!

    I did spend many happy hours at home teaching myself BASIC on our family's Sharp MZ-80A

    1. John Brown (no body) Silver badge

      Re: Tape loading

      "our family's Sharp MZ-80A"

      Ah you're the one who bought it. I knew someone, somewhere i the UK must have one as I remember a computer magazine once printed a listing for one. :-)

      I always thought it looked like an uncool, more clunky version of a Commodore PET that engineers slapped together to get to market as quickly as possibly, by-passing the designers completely.

      1. big_D Silver badge

        Re: Tape loading

        The MZ-80B was the one I lusted after, it looked much more "complete", with the tape deck mounted vertically next to the screen, so the overall shape was more "finished".

  12. Anonymous South African Coward Bronze badge

    The dreaded R Tape Loading Error after saving a ton of typing in

    1. deanb01

      Bizarrely the ZX81 did not have an error code for a failed tape loading (just checked my manual). That was introduced on the Spectrum. I think the ZX-81 just stuck in the loading routine.

  13. ForthIsNotDead

    R tape loading error, 0:1

    Is etched into my brain.

  14. deanb01

    Fond memories

    Cut my programming teeth on a ZX-81. Despite it's basic configuration it was a great little micro. The literature in the early 80s was fantastic, and the hardware was simple, so it was quite easy for your average 10-12 year old to pick up a little bit of assembly language or indeed a basic knowledge of digital electronics (the ZX-81 was also available in kit form for the more adventurous).

    The manuals for the ZX-81 and Spectrum still hold up as being an example on how to write a technical manual for the layperson.

    I remember it being a bit of a pain to write assembly language on it - there being no facilities to store or reserve memory for the code. The solution was to store the code in a REM statement at the top of the code. I must have worn out the tips of my fingers creating REM statements with sufficient characters in to store my code.

    Thankfully, by the time I came to do serious coding (games) the Spectrum had come along, and you could reserve the top of memory for code.

    1K was a challenge - 16K seemed like an absolute luxury at the time. I still write code with memory and efficiency in mind, despite the best efforts of bloatware runtimes.

    Still got my ZX-81 and fire it up occasionally for old times sake.

    1. Paul Kinsler

      Re: Still got my ZX-81 and fire it up occasionally for old times sake.

      I fired up my BBC B last time I was back. "Bang!", went the power supply. :-/

      1. deshepherd

        Re: Still got my ZX-81 and fire it up occasionally for old times sake.

        Same happened to me a couple of years back when I was a Scout Leader and we decided to have a computer games night and my demo of historical computer gaing on the BBC B ended in a suitably dramatic "pop" and white smoke halfway through the evening!

  15. Lee Taylor


    3D Monster maze thats all you need to say about the 81!

    1. Little Mouse


      I just recited the Clown/Ring-Master's "Roll up, roll up" intro to myself. Verbatim.

      It's still stored away up there, unlike much of the French, Shakespeare, etc that I was actually trying to memorise at the time...

  16. Potemkine! Silver badge

    Ah, memories...

    The 16KB extension was a PITA because of its frequent disconnections when the computer was accidentally moved, as was the tape recorder way to save and load programs...

    Nonetheless, we spent many hours as teenagers with a friend on our ZX-81s learning BASIC first and Assembler programming next, many hours of fun and wonder discovering programming. Not surprisingly, we both became developers in the following years. Thanks ZX-81, you little box enabled us for a reasonable price to discover a new World! I still have you preciously stored in a drawer, next to my beloved ATARI-2600.

    1. Ryan Clark

      Re: Ah, memories...

      My main memory was spending a considerable amount of time typing out the code from a magazine before my brother knocked the desk set up in front of the TV and it reset and I had to start again. Don't actually remember playing games or the code, just the annoyances.

  17. Zog_but_not_the_first
    Thumb Up


    ...a minor cascade of loving tributes to this brilliant little machine.

    Feel free to add mine.

  18. Christian Berger

    I have a ZX80 with the ZX81 upgrade

    So I didn't have the "slow mode".

    Using tokens to store BASIC code wasn't uncommon back then, as it not only reduced the memory footprint, but also gave you faster BASIC execution.

    Such low end home computers also nicely show where the line between a "single purpose" computer and a real universal one lies.

    1. Simon Harris

      Re: I have a ZX80 with the ZX81 upgrade

      Using tokens to store keywords was quite common on many computers back then, but the tokens were usually expanded to keywords only when the LIST command was used.

      On the ZX80/81 the tokenised keywords were displayed in full even from within a program if you had a line PRINT CHR$( x ) where x corresponded to the value of a keyword token. Using PRINT CHR$( x ) on most computers would normally display a single character or some screen control action such as clear screen or cursor movement.

  19. Outer mongolian custard monster from outer space (honest)

    I had one, well a couple after accidents with shorts and electrical issues, 1k at first, then the infamous sinclair ram pack. Cured wobbly ram pack crashes by gluing zx81 and rampack solidly to a formica board, end of crashes.

    Also decided to get a bit experimental, built my own full size keyboard from a recycled industrial keyboard from the "Computer Junk Shop" in wallasey (magic emporium) which at the time was jammed full of weird stuff and PETS and decomissioned mini's amongst other wonders and learnt about keyboard matrix's etc. Also added a extra chip piggybacked on the char rom, and this meant that the ascii charset got shunted into ram and could be edited for customisable graphics!

    Also remember the wonderful "Buzz" organ, which drew bands onto a CRT tv causing it to hum loudly with the abuse. Different keys produced different band frequencies, which caused different tones of hum, voila a organ on a machine with no sound hardware.

    For tapes we found a certain brand of small tape deck was perfectly matched, and I still have one today (it was a sharp, I'd have to go dig it out as my zx81 today is a display cabinet thing rather than in actual use, and its original not sprouting hook up wire out of every melted in hole in its casing like my real one was)

    Did the writing stuff in z80, then encoding it into hex, then ascii, and storing it as a load of REM statements and jmp into it to run like another poster above. Tedious but fun to learn and do. It was just what you did back in those days wasn't it? I think it was fantastic and I really pity a youngster of today trying to try and understand the innards of a x64 apu based black box system to the same level we were able to read and understand that simple little 8 bitter. I showed my son zx81 basic and helped him write the classic hello world goto 10 3 liner in it on the actual computer and he got it straight away, so still some value in simplicity.

    Also have the cushions in my gamesroom with mazogs on them, ascii graphics being perfectly suited to replication in patchwork designs, also in tiling, although the floor has a giant space invader tiled in, as my wife said mazogs would be a bit too obscure if we ever sold the house :D

    Nostalgia, still, glad time and performance has moved on, and the original keyboard is still bloody awful even today.

    1. CrazyOldCatMan Silver badge

      Also remember the wonderful "Buzz" organ, which drew bands onto a CRT tv causing it to hum loudly with the abuse

      I remember trying to make music using the 'polyphonic' sound chip on the BBC B. Was very proud of the 'song' I made.

      Trouble was, when I came to ask my friend to add a guitar over the top (using his advanced 4-track tape mixer) we discovered that the tones used by the BBC were nothing like correct in pitch.. So, even though the song was supposed to be in C, in actuality it wasn't.

      So, of course, I blamed the computer rather than my musical skills. What else are computers for?

    2. Anonymous Coward
      Anonymous Coward

      Minimalist Electro on the ZX81 (and why programming an x86 isn't)

      "Also remember the wonderful "Buzz" organ, which drew bands onto a CRT tv causing it to hum loudly with the abuse. Different keys produced different band frequencies"

      I did that too! Found a program in my Dad's old "Sinclair Programs" magazine that- IIRC- toggled between FAST and SLOW modes producing an audible buzzing then experimented myself with delays and other effects (repeatedly sending a COPY to the printer when there was no printer attached also made noise IIRC.)

      There might still be a tape of 10-year-old me singing nonsensical- and frankly strange- lyrics alongside the alleged "music" I made this way. It'd probably be hailed as a minimalist Kraftwerk/Numan-influenced electro masterpiece nowadays. (#)

      Also, you can- in theory- still program an x86 based computer using assembler, but it's worth remembering that since the Pentium Pro and Pentium II came out, all recent Intel processors (and presumably AMD by now) use a completely different internal microarchitecture and instruction set.

      Some have described this instruction set as RISC-like, though others dispute that (##)- regardless, the important part is that it's *not* x86. The x86 instructions are converted on the fly via a decoder into the native format, so even any "native" x86 code you write is still effectively being run under emulation by a completely different architecture anyway!

      (#) It wasn't, I preferred ABBA, even though this was 1986 and they, Numan, Kraftwerk and the ZX81 were all passe by this point. I got an Atari 800XL soon after this...

      (##) Since this internal instruction set isn't- AFAIK- exposed or available for regular programming use, there's nothing stopping them from completely changing its design to suit themselves anyway; all that has to change is the x86 emulation "API".

  20. Nugry Horace

    15 SCROLL

    Otherwise the program will stop with error 5 when it reaches the bottom of the screen.

  21. James Cullingham

    Every byte counted

    My 'favourite' feature related to the storage of numeric constants that formed part of a line of BASIC. As background, you have to bear in mind that the machine was very storage constrained, but also very performance-constrained, especially when it came to FP arithmetic.

    Say, for example, you had a line

    10 LET A=1

    10, as the line number, was stored in 2 bytes

    LET was a keyword, so was stored as a single byte token

    A and = obviously took 1 byte each

    But then came the numeric constant 1. Due to the performance hit of parsing that into an 5 byte FP representation (1 byte exponent, 4 byte mantissa), this was done as the line was entered, so what actually ended up in memory was the code for the character 1, followed by the marker byte 0x7E, followed by 5 more bytes of data.

    Horror! One character took 7 bytes!

    It was actually more efficient to write instead

    10 LET A=PI/PI

    because PI was, again, a single byte tokenised keyword, so now you had 3 bytes instead of 7 - a substantial saving and one that would add up over the length of a full program.

    Similarly 3 was INT(PI), and arbitrary constants were, IIRC e.g. INT("12345") (still saving 3 bytes).

    You got the performance back by writing every-increasing amounts in machine code (process: write it out, then hand-assemble, then create a hex entry utility, then type in the entire codebase in hex)

    And you saved bytes in your machine code by referring to your disassembly of the entire ROM (published as a book -,%20O%27Hara%29.html) to see if you could abything from a full routine down to a few bytes here and there.

    Happy days!

  22. WozNZ

    10 PRINT "Hell

    arrgh bloody ram pack wobble

    10 PRINT "Hell

    oh ffs, again. really

    Place I cut my first code :)

  23. Soul assassin

    3d monster maze!!! Scariest game in creation!!! :)

    1. Michael Strorm Silver badge


  24. Hockney

    3D Monster Maze

    The best computer game ever.

    Okay, it was all in your imagination, but it had a maze. And a dinosaur. You ran until you died.

    Perfect life lesson

    1. Anonymous South African Coward Bronze badge

      Re: 3D Monster Maze

      Precursor to Wolfenstein and DOOM...

      1. deshepherd

        Re: 3D Monster Maze

        ... and looks like a sucessor of Minotaur for Acorn Atom - which according to the interwebs is a game wot I wrote. I worked at Acorn in the year before University and I think this was one of the items I ended up as author because I was the last person to work on them. Think on this I took what was an exisitng 3d maze program and added the "move the gold bars to the safe while being chased by the minotaur" bit. Anyway, it appears I may need to add "inventor of the 3D FPS game genre" to my CV!

        1. Simon Harris

          Re: 3D Monster Maze

          Have an upvote - I remember playing that one!

          Back in those days I reviewed a few Atom games for Computer and Video Games - it's quite likely I reviewed that one.

  25. jrd


    First, type in 1 REM followed by 620 zeroes...

    --- on a keyboard with no repeat where the screen redraw takes a measurable amount of time and happens after each keypress...

    1. Anonymous South African Coward Bronze badge

      Re: Nostalgia

      Why would you want to do that? :)

      1. GrumpenKraut

        Re: Nostalgia

        > Why would you want to do that? :)

        To fill it up with machine code?

        1. jrd

          Re: Nostalgia

          Correct. You'd then write a small loader program which would allow you to enter hex machine code into the REM statement. You couldn't safely load machine code directly into memory as this would be cleared automatically when you typed RUN so hiding it in a REM statement was a common trick.

    2. ThomH

      Re: Nostalgia

      Now do it on a ZX80 where each keypress is followed by a screen bounce as the CRT tries to resynchronise with a video signal that momentarily went missing. The ZX81's constant display is virtually space age!

  26. OldPalmFan

    I designed a bridge on my girlfriends' ZX81

    I was a Royal Engineer officer and had a task to build a wooden foot-bridge at a National Trust property. The design process was iterative; you guessed some dimensions, ran them through the calculations in the Improvised Bridge Design manual to see if the bridge was strong enough and if not could see what bits needed to be bigger (keeping it simple for you Register types). Perfect for a computer programme, I thought and my girlfriend had 'a computer' a ZX81 complete with wobble-pack. So I wrote a programme that worked through the iterative steps and ended up with a design. Somewhat proud of this I listed the programme in my design report CO completely po-poohed the idea of using a computer and thought it ridiculous that they could ever be of any use in RE tasks. A visionary he was not. After I left the Army I moved into IT where I've been for the last 25+ years (but not programming, I'm rubbish at it but the bridge was built and didn't fall down!).

  27. roger 8

    I had the zx81 my mate had a spectrum. Born in 69 was the right time. by the mid 80s when I was in comprehensive school we had Commodore PET and BBC B micro and a little bot with a pen. I think the program was called LOGO. pen up move 10 right 90 pen down move 10. I remember me and a friend drawing out the full map for manic miner on graph paper and sticking it to the wall. it was a big map. I remember my dad coming home from work wtht a parcel and gave it to me. said the IT guy from head office had brought it ( dad worked for Ciba-Geigy at the time.) it was a massive printout of a game. on green and white listing paper. looked like something from nasa. took me ages to type it all in and save it to audio tape

    1. dc_m

      it's called mslogo now.

      The "little bots" are known as turtles, they are still being used. There are variations of basically the same thing.

      It would have been a variant of the original valiant roamer. Uses two massive lantern batteries. I know for a fact schools were buying these no more than 8 years ago.

  28. Anonymous Coward
    Anonymous Coward

    Yup my first

    With 16K ram pack!

    1. salamamba too

      Re: Yup my first

      My first computer as well, but with a 64k japanese ram pack that negated the warranty of the computer the moment you used it.

      Always fun when speccie users boasted about their 48k.

  29. fixit_f

    My school had a dedicated computer room with about 12 of these, and we’d have lessons where we worked on them in pairs. The teacher would line everyone up outside with no shoes on and then get each pair of kids to creep in and sit down as slowly as possible – any more people moving at a time and there was a good chance the expansion packs would move in several of them and they’d re-set, causing whatever program we were looking at to need to be reloaded from tape.

  30. jms222

    BBC Basic

    At the museum I really enjoy watching people of _all_ ages pick up BBC User Guide or our booklet and start playing. The biggest issue is that BBC Basic is uppercase. "Mistake" doesn't quite convey this.

    Ah Ciba-Geigy. I did a contract at a related company Techne in Duxford not that along ago working on Motorola 68HC code continuing my largely 8 bit career that started with the Z80. We used their canteen and would wander onto their site at lunchtime.

    1. Simon Harris

      Re: BBC Basic

      "The biggest issue is that BBC Basic is uppercase"

      Back then I think almost all BASIC was upper case - at the beginning of the home-computer explosion it was quite a luxury if your computer could even display lower case.

      1. deshepherd

        Re: BBC Basic

        I suspect upper case may have been a BBC requirement as they wanted it to look like other Basic's of the day.Had it not been for then I think "Acorn Basic" was going to ditch line numbers and use labels which would only be needed for GOTO/GOSUB targets.

      2. Christian Berger

        One has to be fair

        Lower case letters were only invented in 765.

  31. Anonymous Coward
    Anonymous Coward

    Over 40 and used one of these?

    nope. Not a chance. I got burned off of anything with a 'Sinclair' label on it with his Radios. Useless POS. Components were 'engineered' out to reduce cost which had a byproduct of reducing reliability.

    As for the Sinclair 'Digital Watch'... sigh.

    As I was working for a Computer Manufacturer at the time I had big boys toys to play with at work. 32bit Multi-User Operating Systems and 256Mb Disk drives that could be made to dance over the floor. As a result I never felt the need to get involved with any of this stuff.

    1. Anonymous Coward
      Anonymous Coward

      Re: Over 40 and used one of these?

      Not sure why the down votes for my fellow commentator above, the comment has merit. Having spent the last 5 years researching many of "Uncle Clives" firms and having collected one of each of most of his companies devices, many of them were frankly crap. Sorry. Some were design classics such as the Neoteric or the Forum Phone, but others, while pretty to look at, just didn't work eg, the Black Watch or Stereo 60

      Too many people seem to have a very rose tinted view on his work. While he may have brought many technologies into to home or workplace due to "at the time" great prices and a bit of style, many were just not as good as many of the competitors at the time.

      anonymously - I don't want to f*** up any chances for my forthcoming book........

      1. Anonymous Coward
        Anonymous Coward

        Re: Over 40 and used one of these?

        Think it might have been the "I worked in a job where I got access to whizz bang fancy computers, so I'm alright Jack" attitude as well.

        "As a result I never felt the need to get involved with any of this stuff."

        Yeah, good for him/her being lucky enough to be able to look down their nose at it in the first place. Not everyone- well, let's be blunt, not many people- would have been in jobs where they already had access to all those "big boys toys".

        I for one didn't, possibly because I was six years old at the time.

        Don't think anyone was under the impression that the ZX81 was the powerful leading edge of even home technology at the time. The Atari 800 (for example) was light years ahead... on the other hand, it would have cost- AFAIK- approaching ten times the price of the ZX81 on the UK market. Which is pretty much the bloody point- most people wouldn't have been able to afford an Atari 800 or Apple II, but the ZX81 was affordable.

        The blunt truth is that the ZX81 was the first opportunity many people would have had to play with a computer of their own (or their first experience of a computer full stop). Most of its limitations and idiosyncracies- bad RAM pack design excluded- could be forgiven on this basis, even if it was superseded by better machines fairly quickly. (Not least by Sinclair's own Spectrum, which was far from perfect either, but still the first computer at that price capable of hi-res colour graphics that could passably approximate arcade games; maybe less so in the "sound" department, though...)

      2. Andy3

        Re: Over 40 and used one of these?

        Hmm. I grew up making Sinclair kits and every one of them worked. The little radios (I had a Micromatic) worked fine and My stereo record player used two Z30's and a Stereo 60 pre-amp unit. All fine and lasted years. We even made an amplifier for our mobile disco using two Z50's and a PZ8. This may sound like a recipe for disgruntled dancers, but it only ever went off once - and it came back perfectly after a reset. I honestly think many of the complaints about Sinclair stuff come from people who built it badly.

    2. Phil O'Sophical Silver badge

      Re: Over 40 and used one of these?

      I got burned off of anything with a 'Sinclair' label on it with his Radios. Useless POS.

      Not everything. My original Sinclair Scientific still works, RPN logic & all!

      1. Andy3

        Re: Over 40 and used one of these?

        And I still have my (working) Cambridge calculator which I bought in 1974 (I think).

    3. Alister

      Re: Over 40 and used one of these?

      I bought the Zylog Z80 Programming Manual, with MY OWN money, on the strength of having a ZX81, and taught myself assembler.

      Unfortunately, when I started college 6 months later, all the Computing courses were done on Rockwell AIM65 machines, so I had to start again...

  32. MikeCorris

    My friend had a ZX81 for his birthday. I remember we used to lie on the floor in front of the telly laboriously typing as previously mentioned. When the 16K RAM pack came out we couldn’t imagaine anyone needing 16K! Eventually he got one of course and ram pack wobble became our nemesis. I got a 16K Spectrum some time later. After having that for a while it got sent away too have the 48k upgrade for my birthday. It arrived before my birthday but I was told not to play any 48K games until my birthday! Can’t believe it looking back but my mate got me a copy of manic miner and we used to play it secretly when my dad wasn’t there! Those were the days...

  33. AS1

    No wobbling here

    Never had a problem with RAM pack wobble; maybe I received the only Sinclair pack with a good connector, or maybe because I plugged in the pack once, and never removed it. It even survived being dropped a couple of inches while running a Nightfall clone at the local CUG held in a function room over the local (see icon, for the parents of course).

    I miss the manual; everything nowadays is so poorly documented and seems to rely on users helping one another. Cheap but inefficient.

  34. Anonymous Coward
    Anonymous Coward

    Ah, the memories. Excuse me while I find the bleach...

    My first computer, and the reason I learned Z80 machine code (lddr made for some interesting scrolling games...). Made my own joystick, attempted to make my own RAM pack...

    Also the gateway to a long career in IT. Very few regrets.

  35. DJO Silver badge


    Then as a reader of Wireless World I thought the ZX series was for kiddies so when WW published a design ( I saved up my pennies and built one, oh the fun of soldering 5k of 1 kilobit chips (with parity) that's 45 x 20 pin chips and then actually getting the bugger to work was a great source of joy (for "joy" read "frustration").

    But once it did work it was an interesting machine boasting a calculator chip as a "maths co-processor" which allowed far more complex programs and a novel version of BASIC using reverse polish notation which had the great advantage of confusing the hell out of almost everybody who saw it.

    Learned a lot about computer hardware and how to do terse programming, a skill that seems to have been lost now as memory and storage are cheap and abundant.

  36. Ken 16 Silver badge

    I had a ZX80

    because it got discounted when the ZX81 came out

    I spent hours typing games into it and never getting them to load from tape successfully after.

    I bought an ICL OPD when I was in college (spectrum with knobs on).

    Never follow my example when buying any technology.

    1. Lotaresco

      Re: I had a ZX80

      "I bought an ICL OPD when I was in college (spectrum with knobs on)."

      Errm the OPD was a Sinclair QL with a built-in telephone handset. The similar device that was a Spectrum with knobs on was the Amstrad emailer.

      1. Anonymous Coward
        Anonymous Coward

        Re: I had a ZX80

        IIRC the Amstrad Emailer had nostalgia-exploiting Spectrum games available- presumably via emulation- but I don't think the machine itself was a "Spectrum with knobs on" either.

        1. Uncle Slacky Silver badge

          Re: I had a ZX80

          I think maybe the SAM Coupé might qualify as a "Spectrum with knobs on", failing that, the TS 2068?

          1. ThomH

            Re: I had a ZX80

            The SAM Coupé is a "Spectrum with Prince of Persia on (and not much else)", and I loved mine dearly.

    2. Anonymous Coward
      Anonymous Coward

      Re: I had a ZX80

      Both ZX80 and OPD worth a fair bit if you kept them, so maybe not such bad choices.

      I bought a Jupiter Ace. Look how much they are worth now.

      I continue to regret binning mine when I couldn't after all get on with Forth

    3. Anonymous South African Coward Bronze badge

      Re: I had a ZX80

      Dabbsy, is that you?

  37. GlenP Silver badge

    Still got one...

    Having started to learn programming at school on an RM 380Z I spent my paper round money on a ZX-81. It did get upgraded with a 32K memory pack (which was a bare board, uncased as that was cheaper!) Once at Uni and with a bit more money available in those full grant days before student loans I upgraded to a Spectrum. With help from a flat mate I built a fully programmable multi-button joystick for that (advantage of the keyboard matrix being presented on the expansion bus) which was brilliant for playing Halls of the Things as you could easily access all the weapons.

    In third year I acquired a Beeb Model B cheap, someone wanted the floppy upgrade and wasn't prepared to do the minor PCB mods so bought a new one and sold the old one second hand. The irony was he went from an Issue 7 motherboard back to an Issue 3, but he wouldn't listen. I think I used the Watford Electronics kit to then install a floppy.

    They've all long gone now as houses have been cleared, etc. but a friend recently offered me an apparently working ZX-81 with RAM pack for a small charity donation. Unfortunately it's not boxed but it's now a display piece.

  38. Paul Cooper

    Not a ZX81, but I did program a Z80 based single card computer with very similar memory limitations and NO Basic or OS of any kind! As I was doing real-time data logging, I got very familiar with the vagaries of the Z80 interrupt system, and have ever since been very aware of how little memory you actually NEED to do quite advanced tasks.

    I also used BBC B Micros quite a lot - the trick of using REM statements to enter assembly code is one I remember!

    1. John Brown (no body) Silver badge

      "I also used BBC B Micros quite a lot - the trick of using REM statements to enter assembly code is one I remember!"

      Was that needed when BBCBasic had a built-in assembler? Or was that another space saving method?

      1. davidp231

        "Was that needed when BBCBasic had a built-in assembler? Or was that another space saving method?"

        Nope. No shortcuts needed. The only space saving really would be abbreviating BASIC commands, but they just get expanded when you LIST.

        10 <print whatever>

        20 <set variable to zero>

        30 {

        40-90 <assembly code>

        100 }

        110- <rest of program>

  39. Phil A.

    It's no exaggeration to say the ZX81 shaped my entire life!

    I first saw one when I was babysitting for a friend and they'd just got one. I was immediately captivated by what was the first computer I'd ever used "hands on" and saved all my money to get one of my own.

    I taught myself Z80 machine code but as I couldn't afford an assembler program, I hand translated the assembler into machine code and sold a game to DK'Tronics for £200 and a ZX Spectrum (which seemed like all the money in the world to a 16 year old me)

    Since that moment, my entire life has revolved around computers and software development and even now (37 years later) that's how I put a roof over my head and food on my table

    For me, the ZX81 launch was quite possibly the most important event in my life and one for which I'll be forever grateful

    1. ChrisCabbage

      Yeah - I sold games to DKtronics too (also for a Spectrum), but they went bust before release. They were targeted for the graphics swap-out chip they were selling.

    2. Jame_s

      what was the game called?

  40. Anonymous Coward
    Anonymous Coward

    There's one in use even today...

    Yep, a ZX81 being used 'professionally'.

    Although they are shutting it down at the end of this week.

    The ZX81 is just calculating its final payroll under the Government of Canada's Phiasco Payroll Program.

    Over the weekend, they're upgrading to a VIC20.

  41. TRT

    I remember programming it...

    to calculate the ultimate answer to life, the universe and everything.

    It returned 4/2000

  42. ChrisCabbage

    I cut my teenage programming teeth on the ZX81. Writing games in Z80 assembler, which I managed to sell (before the company went bust).

    It was all magical! :)

  43. Andy The Hat Silver badge

    For sale

    Got 2 zx81s in the shed, a full Micro Professor system (who remembers those?) and an Oric 1 in the loft. Very cheap but obviously getting dangerously close to antique status so may quadruple in price due to Brexit ...

  44. GrumpenKraut

    16k Rampack...

    I vividly remember getting it, thinking "what shall I even store on that much RAM?"

    Now for the "down-vote me harder"-part: It never EVER wobbled. Also the keyboard worked without a glitch. And both storing and retrieving from tape worked reliably as well.

    Learned machine code only on my next machine, a "Pineapple" (clone of the Apple ][, as you guessed). Had to assemble (and solder) that thing myself. Due to lack of funds after that I made the case out of discarded furniture parts. Sturdy it was.

  45. Anonymous Coward
    Anonymous Coward

    Sound card?



    Stick that into a 1k zx81, turn up the (tv) volume, listen to the beeps!!!

    1. AndrueC Silver badge

      Re: Sound card?

      Or for some screeching and border flashing try: RANDOMIZE USR 1331 on a Spectrum.

      That jumps you straight into the tape loading code. Press the spacebar to exit :)

  46. Anonymous Coward
    Anonymous Coward

    Not Only 30 Programs for the Sinclair ZX81 1K

  47. Spanners Silver badge


    About the same time, I went to college. They had a "mainframe". In my first year, I had a keyboard and printer. The next year, I had a screen!

    As I was not doing the right subjects, I got no lessons. I did get the various programmes like Lunar Lander and Artillery.

    From that and a knowledge of algebra, I wrote a programme to do the sums for a levels survey - you know one guy walks along a projected new road holding a big pole with numbers on it and someone else looks at it through a telescope on a tripod.

    A few years ago, I found a copy of it and showed my boss. He was impressed when he saw the date on it - 1980/81.

  48. Andytug

    There's still a ZX81 in our loft somewhere...

    Was working last time it was plugged in! (20+ years ago)

    As well as 3D Monster Maze, remember a maze game called Mazogs and also somehow a hi-res (but still (black and white) version of either Manic Miner or Dig Dug that came out shortly before the Spectrum did. No idea how the hi-res (OK, 480i) graphics were done though. I remember the tape for that very rarely loaded properly.

    1. ThomH

      Re: There's still a ZX81 in our loft somewhere...

      There's a 1980s Czechoslovakian port of Manic Miner to the ZX81; if you're thinking of that then I'm pretty sure it is one of those gets something very much like high-resolution graphics by using a part of the ROM that isn't the character set as the lookup table for the character set and making do with the best distribution of bytes it can find.

      You could also get a genuine all-pixels-addressable mode by sneakily ensuring that nobody provided character set graphics at all, but it was hit or miss whether it would work with any given third-party RAM expansion and you don't get many pixels into the built-in 1kb.

  49. hardboiledphil

    My parents bought the kit for me and my uncle (who worked on library computer installations) built it up. Later I got the Memotech 16kb pack (no wobble) and then said uncle fitted like a large rs232 connector to the side of the machine and from then on I could plug in an external full size keyboard. Later I got the Memotech high res pack (192*256 ??) but wasn't much around to use it.

    It did teach me BASIC though and the last 22 years I've been a developer in some form or other.

  50. /dev/null

    RAM pack wobble

    I believe the root cause of the the dreaded wobble was that Sinclair re-used a RAM pack casing design intended for the ZX80 (which had a flat, vertical rear surface for the pack to butt up against) for the ZX81 (which didn't). See Rick Dickinson's sketch of his intended ZX81 RAM pack in his fascinating (if you're an old Sinclair nerd) Sinclair design archives on Flickr.

    1. Anonymous Coward
      Anonymous Coward

      Re: RAM pack wobble

      Ah ... the old reusing an existing design that doesn't quite fit the new model story. On the Acorn side I recallgearing Chris Curry was muying a limited number ofcases for keyboards for the Acorn System 3 but after he checked the size of the Acorn Atom circuit board and seeing it was smaller than the case dimensions its said he greatly increased the order to get a much better price and to have cases ready for the Atom. Unfortunatety turned out he'd compared the board size against external dimensions of case and it wouldn't fit - so they had to shrink the circuit board which meant losing a column of RAM chips - hence the rather odd 5.75kB of program memory with a 256 byte gap at the top!

    2. Anonymous Coward
      Anonymous Coward

      Re: RAM pack wobble

      @/dev/null; Yes, that's the explanation for the notorious RAM pack I heard as well.

  51. Anonymous Coward
    Anonymous Coward

    I am drawn back in time

    watching speccy kids at the back of WH Smiths all shoving each other aside to have a go at the Oric 1, ZX81, Electon etc..

    My house ended up with a BBC model B though. Little cassette recorder to the side, Microvitec Cub RGB monitor in front bought from Alan Sugar's Viglen.

    I am sure I got my dad to buy almost every game from Superior Software too- must have kept those guys in coffee for a while.

    All got more exciting when a Uni friend of my parents started to tell me how to draw circles using Sine and Cosine and went on from there.

    Enterprise apps are so boring and functional now :) although I never had any idea at the time that computers would be in my adult career.

    1. Anonymous Coward
      Anonymous Coward

      Re: I am drawn back in time

      "Microvitec Cub RGB monitor in front bought from Alan Sugar's Viglen."

      Almost certainly wasn't owned by LordSirAlan at that point. While at University I bought a floopy drive from them - they seemed to be cheapest ad in PCW etc and, in those pre internet ordering days and as I had just got a car I drove down M40 form Oxford to some address on an industrial estate in North London where it was clear that Viglen were a company that made plastic boxes but had just twigged that if you put a floopy drive inside the plastic box the profit margin was vastly higher .... though I suspect their low prices were because they were still thinking in terms of plastic box margins and not computer equipment margins!

  52. Ian Entwistle

    Still have mine

    I take my ZX81 and VIC-20 when i do STEM events ( careers fairs, talks about careers in general, early days computing talks etc ). I find them great Ice breakers and the kids are amazed we could do stuff with so little RAM etc. when you explain tuning the TV in to see the screen you just get blank stares...

    Still reckon it was THE best 50 quid I ever spent as I now have a great career that I love that pays far more than the "teacher" option that I was expected to follow.

    Thanks Sir Clive!!!

  53. iron

    A borrowed ZX81 was my into to programming before my dad bought me my beloved Speccy. Looking back 35 years later, old Sir Clive has a lot to answer for! Including a lot of happy memories. :)

  54. GruntyMcPugh

    3D Monster Maze!

    A blocky '3D' maze, ... a blocky 'T-Rex' a couple of scared small boys,....

    What I miss about this era was the variety. My mate Jeremy had a ZX81 and then a Spectrum,.... I tried to buy the ill fated Oric~1, but eventually gave up waiting and got an Electron instead, another mate Craig had a Dragon32, and another a Ti994a, others swore by their Commodore. I worked at Woollies as a Saturday lad, and we sold Commodore, Atari, Amiga, and Sinclair computers. It was great fun comparing what each machine could do, how ported arcade games looked on each platform, etc.

    Oh yeah, and there was Pete, ... who ended up with a Sharp MZ80k, the poor bastard.

  55. JcRabbit

    Sinclair jump started programming in Europe

    Oh man, the memories! :) I started with the ZX-81 but quickly moved on to the Spectrum:

    LD HL,16384

    LD D,H

    LD E,L

    INC E

    LD BC, 6912

    XOR A

    LD (HL),A


    Anybody remembers what that does? Can be written in a simpler way, but, IIRC, that is still the most efficient way in terms of T-States alone. :)

    So, a friend got me the 'Complete ZX Spectrum ROM Disassembly' by Dr.Ian Logan and Dr.Frank O.Hara. The bible of programming Assembly Z80 on the Spectrum! Based on it I ended up doing a copier called 'OmniCopy II' (there was never a version 1) and the thing kind of spread everywhere: the copier got copied eheh. Never put my name on it, so it was bittersweet reading about it in local newspapers and foreign computer magazines... :)

    1. AnonymousCoward

      The good old days

      It zeroes a block of memory 6192 bytes long starting at 16384 (0x4000) in the memory map.

      On a ZX81 this would corrupt your system. On a Spectrum it would clear the screen and attributes.

      Thanks for the brain cell challenge. Made me dig in a few dark corners.

      1. Cynic_999

        Re: The good old days


        It zeroes a block of memory 6192 bytes long starting at 16384 (0x4000) in the memory map.


        In fact the block cleared would be 6193 bytes long with that code. (Go through it with BC being loaded with 1 instead of 6192 and you will see that 2 bytes of memory are then cleared)

        1. AnonymousCoward

          Re: The good old days

          Oops, you are correct. The initial LD (HL),A clears the first byte, the LDIR then clears BC more.

          I wonder how many times I made that kind of mistake back in the day.

          1. Anonymous Coward
            Anonymous Coward

            Re: The good old days

            "There are 2 hard problems in computer science: cache invalidation, naming things, and off-by-1 errors."

    2. DJSpuddyLizard

      Re: Sinclair jump started programming in Europe

      So, a friend got me the 'Complete ZX Spectrum ROM Disassembly' by Dr.Ian Logan and Dr.Frank O.Hara. The bible of programming Assembly Z80 on the Spectrum!

      I had one, too.

      The really cool thing to think about now, is that you could just about understand the whole system.

      You understood to some degree the hardware, what each chip did, the assembler instruction set, the programs, and maybe even how the BASIC worked. Of course I had to look up Chebyshev polynomials, but you can see how it uses them, even if you don't fully grasp the math.

      Now, I really don't understand what cross-site XML phalumph scripting has to do with my ISO viewstate enterprise modelfactory anymore, and these days I have to research stored procedures I wrote last month, because they're so complex.

    3. Anonymous Coward
      Anonymous Coward

      Re: Sinclair jump started programming in Europe

      LDIR (repeating block load with increment) was the most inefficient way to clear the Spectrum screen space when it comes to T states. The code is one of the shortest in terms of memory bytes used though. Disassembling Ultimate Play the Game titles from Ashby Computers and Graphics ltd, I came across a much lengthier piece of code using simpler instructions (a RISC approach) that cleared the screen far, far, faster than using LDIR. Not surprisingly this technique was used in their isometric games and I recall they even wrote their game screen to part of the speccys high memory area and used an interrupt to dump the content to the speccy screen memory space. Another aspect of the code was that it wrote to the speccy screen from bottom right to top left which I assume was to avoid a clash with the PAL screen refresh and thus avoiding major flickering on the display. The bible of the day was Programming the Z80 by Rodney Zaks

      1. AndrueC Silver badge

        Re: Sinclair jump started programming in Europe

        One of the fastest ways to assign a repeating 16 bit value to an area of memory on any Z80 based system is to use the stack and unwind the loop a bit. From memory:

        LD HL, SP

        LD A, <inner loop count>

        LD SP, <target address>

        LD DE, <value>


        PUSH DE

        PUSH DE

        PUSH DE


        DEC A ;// Although you can also use BC if you have a lot of memory to clear.

        JR NZ repeat: ;// But you'll also need to upgrade this :)

        LD SP, HL

        A classic case of trading execution speed for instruction 'size'.

  56. spold Silver badge

    Hmmm - what about the predecessor?

    No I mean the original!

    The MK14 - Mr. Sinclair's first computer. Marketed under his original "Science of Cambridge" brand. More of a Microprocessor Kit (hence the MK) it sported an SC/MP processor. 256 bytes of RAM, expandable up to 640 bytes onboard and a max of 4K (if you installed the 8154 I/O chip - this was also able to control external devices and make basic audio tones - the original Smart Home Controller!), If you didn't like the calculator style display (posh git) it could drive a VDU at 32x16 text or 64x64 graphics (well blobs).

    It could write to cassette tape, and in a blue moon month with the wind from the south and no rain it could sometimes even read it back.

    Some assembly required - well a bag of bits and you needed a soldering iron and a lot of patience, oh and some chip sockets unless you wanted to risk frying the processor.

    I had one, and the membrane keyboard was so crap (you had to sit on it to get a key to work) it was quickly replaced with an array of microswitches stuck on a piece of cardboard.

    As for that ZX.. world's most intelligent doorstop. :-)

    1. John Styles

      Re: Hmmm - what about the predecessor?

      You should watch this fascinating long interview about the MK14

      (and the life of its creator)

      A fascinating titbit is that his original plan was to use octal so it could use a Sinclair calculator with its 7 segment displays as the UI (I may have slightly misremembered the detail, but definitely octal)

  57. Updraft102

    Yep, that was the little computer that started it all for me. From there to a Commodore 64 to a Commodore 128 to PC...

  58. People's Poet

    I stopped reading at.....

    "At least the membrane keyboard featured an early version of Intellisense, with commands and functions popping up while the user typed. A proficient user could rapidly fill the diminutive memory with only a few keystrokes."

    No it bloody well didn't! The author has clearly never used one. You had to use key combinations to get certain commands or functions to come up, usually meaning you were holding 3 keys down to get to more advanced commands. Shite journalism to say the least!

    1. Anonymous Coward
      Anonymous Coward

      Re: I stopped reading at.....

      You had to use key combinations to get certain commands or functions to come up, usually meaning you were holding 3 keys down to get to more advanced commands.

      Don't remember that - and there's only one shift key, no Alt or Ctrl or anything.To get the cursor to Function mode, you did Shift-newline, but that changed the mode, never required you to hold all keys down. Likewise, Shift-9 changed the cursor to G for Graphics.'

      You didn't have to hold multiple keys down, but you did have to press quite a few.

  59. davidp231


    This old baby's crashed more times than a ZX81.

  60. Steve Hersey

    Top this...

    I once built some external I/O hardware for a ZX80 to drive solid-state relays. The customer wanted to use it to automate a sawmill. They were disinclined to accept the notion that the ZX80 wan't really an appropriate platform for controlling potentially man-killing machinery. I never did get my AC adapter back...

    1. GlenP Silver badge

      Re: Top this...

      That reminds me...

      I was at a quality control exhibition in the early eighties when inspection equipment was starting to move over to computerisation*. At least one multi-thousand pound machine had a ZX-81 in it (they wouldn't have admitted it but the display was clearly recognisable).

      *The company I was temping for later acquired a fully computerised 3D checker, it used a PDP-8! DEC engineers would fall about laughing before trying to work out how to actually fix the darn thing.

    2. Anonymous Coward
      Anonymous Coward

      Re: Top this...

      I once worked on a project that used an Apple II as an interface between a VAX and a Mitel PABX. It was the only system they could find whose comms card could be programmed for the weird Mitel console data rate (10,000 bps?). Unfortunately the system wasn't really designed for continuous use with extra cards, and it got hot, so it sat in the floor behind the PABX with no lid on, slowly filling up with dust. Worked for years like that, IIRC.

  61. Anonymous Coward
    Anonymous Coward

    A picture says a 1000 words

    If there is one picture that summed up the entire excitement that I ever felt as a teenager that picture at the top of the story just says it all. The picture either means a huge amount to you or zero.

    At the age of 49 that picture just brings floods of memories.

    I, for one, can happily salute Sir Clive without mentioning the C5...oops.

  62. steviebuk Silver badge

    I was too innocent and....

    ....a little thick when I was a kid. Innocent that whenever we'd got to WHSmith I'd only ever type:


    20 GOTO 10

    I never wrote naughty words. Never even thought of it.

    Its now over 30 years later and watching old videos on shows about the BBC and BASIC that I realise why it was 10, 20, 30 and sometimes jumped to 100. They were simple times and I was a bit thick so never investigated but turns out they were in 10s in case you wanted to add lines in between. I believe this was all in the manual but I clearly couldn't be bothered to read that.

    More evidence of being thick was I knew you could load from tape, which I did now and then when would get a free tape from a mag. But I never realised I could of written back to a blank tape. So the odd times I'd sit and type up a game from a book, I would play it then loose it once bored of that session. Little did I know I could of just saved it to a blank tape.

    The only game I 100% remember and enjoyed was a horse racing game that I believe was in the manual.

    I'm an IT tech now but back then I wasn't that interested so if I typed up a game that never worked, I never thought about reading into BASIC and finding out where the bug was. I think the crappy keyboard put me off at the time. I hated that flat keyboard. Always wanted the one with the raised keys.

    1. GruntyMcPugh

      Re: I was too innocent and....

      I never wrote expletives either, but the Oric~1 they had at WH Smith provided some fun. The Oric had some built in sound commands, ZAP, PING SHOOT, and EXPLODE, so if you created a count, just long enough to get out of the shop, then looped around those, that was enough mischief for me.

    2. Anonymous Coward
      Anonymous Coward

      Re: I was too innocent and....

      turns out they were in 10s in case you wanted to add lines in between

      I remember a BASIC on some system (PET, Apple II?) that had a RENUMBER command, which would readjust everything to increment in 10s. Well, almost everything, there was some statement that took a line number as an argument and was missed by RENUMBER. That made debugging fun...

      1. BinkyTheMagicPaperclip Silver badge

        Re: I was too innocent and....

        There was RENUM on the MSX, and also subsequently on the Amstrad PCW - it was not uncommon amongst BASIC implementations as MSX's was Microsoft BASIC, and the PCW's was Mallard. On most systems it also handled renumbering GOSUBs and GOTOs, as those interpreters were too simple to handle labels.

  63. LeeH

    Thank You Mr Chester...

    My primary school teacher brought his ZX80 into class so we could use it during breaks. Someone broke in and nicked it over a weekend. He replaced it with a ZX81 a few weeks later. Someone nicked that as well. The 3rd one stayed.

    Mazehogs and Bomber were the games we played. Vague recollection of 3D Monster Maze. I didn't play often but fond memories made. Good times.

    Girls in the class showed no interest in it but I do remember Mr Chester showing a few female teachers his new toy; they were interested.

    Thank you Mr Dick Chester for sharing your computer with us.

    1. Anonymous Coward
      Anonymous Coward

      Re: Thank You Mr Chester...

      "3D Monster Maze"

      ...that scared me...I wasn't ever ready for the monster!

      1. LeeH

        Re: Thank You Mr Chester...

        I was going to do some work this evening but think I'll wake up an emulator and battle monsters instead.

    2. Dan 55 Silver badge

      Re: Thank You Mr Chester...

      Admit it, his name was Richard, but you all called him Dick...

      1. LeeH

        Re: Thank You Mr Chester...

        Only one lad in the class did. The rest of us called him sir. He was one of the most liked teachers in the school. Was not funny when I hit him in his eye as he picked me up off a table in a drama lesson.

        He had told me off for being naughty a few days before and made me stand against a wall in the playground so I told the other lad stood with me that I was "going to beat him [Mr Chester] up". Well, when he pick me up off the table I thought he was starting. I would have been 9 years old. Poor bloke. He was my teacher that year so we had to patch up.

  64. Kimo

    Knew a kid who had one. Me and the other TI99 owners in my school would make sympathetic noises when he showed it off, then laugh behind his back.

  65. Individual #6/42

    My tuppence

    My First: computer, introduction to machine code (there weren't any assemblers that I knew of) and lessons in ram management (PI-PI took up fewer bytes than 0) and counting chip cycles for alternative instruction combinations. Who counts chip cycles nowadays?

    I managed to fill 16k with a reverse engineered (and enhanced) RM 380Z Star Trek exploration and combat program typed out and debugged over weeks. I had never had any trouble with the RAM pack once I'd used milliput to fix the design. Happy memories.

    1. Boris the Cockroach Silver badge

      Re: My tuppence


      Who counts chip cycles nowadays?

      That was the bane of my 8 bit programming life (after getting sick of rampack wobbles and tapes failing to load that is)

      Having a loverly set of interupt controlled animation and sound routines for a game I designed go TITSUP whenever I enabled the sound.... turned out the processing time for all the interupts was about 3 lines too long and failed to exit the interupt routines before the next interupt arrived.

      Took ages to figure out which part took too long and rewrite into something a bit smaller

      Still got my spectrum sitting in the desk next to me(no PSU though), a MTX 500, and an atari ST(heavily modded) too... one day I'll get around to throwing them all out...

      1. deshepherd

        Re: My tuppence

        "Who counts chip cycles nowadays?"

        Well, us proicessor designers are sadly still obsessed by the number of cycles in a Dhrystone loop

      2. Simon Harris

        Re: My tuppence - counting cycles

        You can still have all that fun programming a PIC in assembly code.

  66. x 7

    I still have one, not been used in 40 years so dunno if it still works. Original packaging long since gone, but fairly certain the cables and power unit are still around somewhere

    Any museum out there want it?

    1. steviebuk Silver badge

      Ask they might take it.

  67. John70

    The first time I programmed a computer was on the ZX81 and it was a security routine. I did it because I saw a game on a Vic20 at school asking for a password and was fasinated by it.

    10 Print "Enter Password"

    20 Input A$

    30 If A$ <> "password" Then GoTo 10

    40 Rem Do Something

  68. adam eyeball

    Still have one on my desk

    I still have one on my desk at work - I saved an analogue TV so that I can show my students what computing was like in my day. It's the pity I can't handle.

    (See your RPN calculator and raise you a slide rule)

  69. John Brown (no body) Silver badge

    Slow news day?

    I still enjoyed reading and contributing to the comments, but a 37 year anniversary? Didn't we do this at 35? And will do it again at 40?

    Surely there a list 8-bit micro launch dates somewhere and we can do many more of these. No matter the make/model, there will be readers here who owned one.

    1. Anonymous Coward
      Anonymous Coward

      Re: Slow news day?

      ... well it is its silver anniversary in hex!

  70. Deltics

    My first step in a journey of 1,00 miles...

    I remember my dad taking me to the local sorting office 37 years ago to collect the parcel from Sinclair, a shiny (well, actually no) new ZX81. One of the pre-assembled ones. I imagine this is why I ended up in software rather than hardware - no soldering required. I never could get the damned thing to load anything from tape, so I had to bash in listings from magazines, and then from that took the step to figuring out that by understanding this "gibberish" I could then change those games and make them do what I wanted.

    And so began my life as a self-taught software developer.

    My own personal computing history then went down a slightly esoteric route. While most of my friends had Speccies or Breadbins (C64's), with a couple of Electron's and even one Dragon32, my upgrade path took me to a TI-99/4a since a lot of my family (large number of aunts and uncles) not to mention my own parents at an earlier time, worked for Texas Instruments. When they pulled out of the home computing market staff they sold off stock to employees at bargain basement prices. Idiosynchratic as it was, it was a damned fine machine.

    My path then returned to a more conventional route, with an Amiga 500 and after teaching myself C and Pascal programming with the multitasking GUI OS I then landed a job building software for this new fangled "Windows" on PC's which seemed positively antique compared to the Amiga (this was before even Windows 3.0).

    Thus began a career in computing and software, all thanks to my late dad and that ZX81.

    I've recently started assembling a museum of that personal computing history (the original equipment having been on-sold or disposed of, sadly not being appreciated at the time for the future value - sentimental or otherwise - that it would hold).

    The one exception being my original ZX81, but that hasn't actually worked since the late 80's. But I have now replaced it with one from ebay in near-mint condition, including original box and sleeve.

    There's something magical about switching on these old machines and seeing them spring to life as eager to please as ever, oblivious to the passing of time that has rendered them obsolete as anything other than curios and objects of affection.

  71. David Roberts

    Generational thing. Passed me by.

    By the time this came out I had been computing on mainframes for a long time so had no real idea that small computers were a thing.

    Only really got into it when the kids were old enough to take an interest, and got an Atari STe which also did word processing and spreadsheets. Games for the kids, of course. Dot matrix printer that could do imitation hand writing instead of the usual fonts.

    Fascinating how a decade of enthusiasms can pass you by if you are the wrong age.

  72. Anonymous Coward
    Anonymous Coward

    Late to the party

    I started off on the Spectrum 48K, which thankfully had a keyboard better than a calculator. The manual, to this day, is still a great primer on BASIC programming. Not a great primer on basic programming, of course. I can hear the academics turning in their graves over the use of GOTO rather than functions!

    That machine got lemonaded while meleeing over a joystick; so we went backwards to a Sharp MZ80 for a couple of Christmasses, then leapt forwards with a C64. To this day I'm grateful to my Dad for putting us through the iterations as it's ultimately been my ticket to a job ever since! I'll be damned if I could still remember how to use the MZ80, but all the other machines I can still bodge my way through.

    I recently returned to the C64, fully re-capping and heatsinking the whole system and the excellent Epyx Fastloader Reloaded cartridge with an SD card reader. You forget how hard programming is without a proper text editor or variable names longer than two characters. The C64 programmers reference is hilarious. The complete opposite of modern editing practise. I don't know, encouraging the use of super-condensed code, avoiding comments, minimal spacing, condensing multiple functions into single line numbers and using near-unreadable short symbolic codes for the BASIC keywords.... The kids don't know how easy they have it with Python and virtually unlimited resources!

    It even encourages you to jump into assembler for maximum efficiency. Hard to find assembler being actively used now, other than for a handful of specialised operating system functions... And even then most of the op system you are reading this on was probably done in C or C++.

  73. martinusher Silver badge

    I never went the Sinclair route

    My forays into early home computing started with a Superboard (6502/ROM BASIC), an Osborne 1 and a Jupiter Ace. The Jupiter was similar in size and general crappiness to the ZX81 but ran FORTH which meant you could actually do useful work with it. I've always thought that the history of computing took a number of wrong turns, one of the really bad ones being computers running ROM BASIC such as the ZX81 and the BBC; these types of machines taught a generation of people not only how to write code but also not how to program.

  74. ricardian

    My first OU course was PM957 "Computing & computers" in 1977. I lived in Brora, Sutherland and all my coding (OU BASIC) was handwritten and sent off to the OU computer centre where it was keyed in and run, the results (warts & all) was then posted (Royal Mail) back to me. Later I did another OU course in computing which had HEKTOR, a small machine akin to the VIC-20 which fed an analogue TV. Great course, began hand assembly before progressing to a "proper" assembler and finally a version of BASIC).

    Later in 1984 I worked in R&D for a large government department which bought a few Commodore PETs. With the invaluable help of Raeto West's hefty handbook I taught myself 6502 assembler and produced some useful programs; some of which included speed-up tricks which avoided floating point operations such as multiplying by 10 by shifting left 3 times and then adding the original number twice. I remember that all the IEEE488 (GPIB) routines were hard coded into ROM and that there were a couple of spare sockets for "home-brewed" EPROMS.

    Then we got the first IBM PCs and shifted to "C" using the Aztec compiler. Still good fun though

  75. AndrueC Silver badge

    At least the membrane keyboard featured an early version of Intellisense, with commands and functions popping up while the user typed. A proficient user could rapidly fill the diminutive memory with only a few keystrokes.

    Actually, no. Like all versions of BASIC that I'm aware of the keywords were tokenised once stored in memory. What the article author is describing is some slightly clever keyboard handling that knew the rules about keywords and automatically put the keyboard into an appropriate shift state such that keys generated token codes instead of letters.

    With a lot of computers you typed 'PRINT "Hello"' and that was 13 characters. However a parser then stored that in memory as <PRINT token>"Hello" which meant it only occupied 8 bytes (note how the space after PRINT can be discarded by having the <PRINT token> expand to 'PRINT '.

    What the ZX81 was doing (and the Speccy did the same) was to put the keyboard into a shift state whereby the 'p' key generated <PRINT token> (Character 0xF5 on the Speccy). This saved typing and simplified the parser but had no impact on the amount of memory consumed while entering program statements.

    How interpreters optimise code storage is an interesting subject. My favourite 8-bit machine was the Amstrad CPC and its version of BASIC stored memory addresses alongside line numbers and variables to improve performance.

  76. MacroRodent


    I never owned one, but borrowed from a friend for a while (enough to experience the data loss from the infamous wobbly RAM pack). One thing not mentioned in the article was that since the screen refresh was almost entirely handled by the Z80 CPU, your program ran much faster if you turned it off. The BASIC had FAST and SLOW commands for this. In the FAST mode, the screen just displayed "snow" until the program execution ended.

  77. cutterman

    Ah, what a blast from the past…

    Assembler, machine language, self-modifying code (to fit in that tiny memory space), peeking and poking. I got an AD/DA converter and ran lab instruments with it! The joys of the tape-recorder (not!)

    One trick I used was to modify the return address on the gosub stack to give me conditional jumps to a different code segment - you could really have fun being able to talk to the bare metal of the processor.

    Object-oriented code - why, all my code was OO, long before I'd even heard of it…

    Happy days :-)


    1. Individual #6/42

      Glad to hear I wasn't the only one playing silly buggers

      with self modifying code and the gosub stack. Have an upvote

  78. Hubert Thrunge Jr.

    Kempston Keyboard & Joystick

    Who had one of those as an upgrade to their Sinclair?

    As a teenage yoof, my friends and I "tested" the prototypes of those as the founder of Kempston Micros was out maths teacher.

    He was a very clever guy, but not much of a teacher sadly, or we were just a completely unruly bunch!

    He left the school and set up Kemspton Micros and the rest is history. One of my classmates went on to write software for him while he was at university.

    Nostalgia ain't what it used to be!

  79. ChaosFreak

    My First Computer Game

    OK, so not a Timex Sinclair 1000 but still nostalgic... I managed to get my parents to splurge on a TRS-80 ("Trash 80") as an "educational device" (not a toy) back in 1981 when I was still in primary school. My big sister (six years my elder) was taking night computer courses at Boston University and so we bought a modem so that she could dial into their PDP-10. I soon figured out where she kept her password and spent hours playing "adventure"... when I finally got a Commodore 64 a few years later, the first games I bought (OK, downloaded from a pirate BBS) were the Infocom games as opposed to the flashy graphics games, which were WAY more engaging. I remember spending almost 48 hours straight solving "Planetfall". But try and tell that to kids these days...

    I did manage to teach myself BASIC from the manual included with the TRS-80, the start of a long and satisfying career. My sister also has spent her whole career coding. I think she made it in just before the home computer industry decided that computers were "toys for boys" and began marketing exclusively to boys. Most of the jobs I worked in the early days had a very healthy (even by today's standards) mix of gender among the programmers, but that was a window that soon closed, unfortunately.

  80. Anonymous Coward
    Anonymous Coward

    I still use mine

    It's in the loft, controlling my central heating. Needs to be started up again whenever there's a power outage but other than that, it's been fine for over thirty years (so far).

    1. Outer mongolian custard monster from outer space (honest)

      Re: I still use mine


      I still use mine

      It's in the loft, controlling my central heating. Needs to be started up again whenever there's a power outage but other than that, it's been fine for over thirty years (so far).


      You sir win the internets. And to think I still feel guilty when I go to my old house and see the underfloor heating controller running on a pentium 90 powered toshiba laptop with a broken screen, running some years out of date version of redhat linux (hedwig I think was the last time it got upgraded, relax its now totally airgapped for some years now, although at one point it was the NAT and fax gateway for the house via a modem at the same time :p ). When I power it up and hear that brick being dragged round on a slate roof from the tiny hard disk and marvel that apache still manages to come up clean and present a working gui, until that bit works parts of my nether anatomy tighten slightly while I worry if I can rebuild it and redeploy all the source to something newer assuming I can find something with the right hardware ports to interface to my homemade controller while wondering if its finally time I swapped it for a atmel based pic system I made a few years back as contingency.

      I bet you have a couple of spare zx81's stashed as DR too...

      1. Anonymous Coward
        Anonymous Coward

        Re: I still use mine

        No redundancy I'm unhappy to report... ebay hunt while the Pest From The West freezes my nuts?

        My old PII266 laptop has been happily running off a CF card for years recording CCTV... quietly. Boots XP in under 20 seconds. When it was my software development machine, battery life trebled running off CF. You could get an IDE to CF converter, clone the drive. 'Board, RAM spares are easy to source on ebay of course.

  81. Stephen Wilkinson

    I started with a ZX-81, then a Commodore Vic-20 and then a Commodore 64 before going out to work doing data entry on a IBM System 360.

    Then off to uni to study Software Engineering and a career (employment more like!) so thanks very much Clive, it's all your fault! :D

    I didn't think the Commodore 64 Programmer's Reference Guide was bad, I've still got mine although I don't refer to it anymore.

    Back to the ZX-81, absolutely loved Mazogs and 3D Monster Maze but 3D Defendr was virtually impossible to play - great times to be growing up.

  82. Android Hater

    Just In Time Stock Control

    Yeah, I wrote a Just In Time Stock Control and ordering system for the ZX81. It needed a minimum of 16KB, 32KB was better. Lots of hacks to save memory: PI/PI for zero, Peeks and Pokes everywhere.

    The data was held on tape and needed loading into the arrays which could take 5 minutes to 10 minutes or longer.

    Amazingly, it worked and reduced our stock holding nearly 70%! I seem to remember even selling it to a number of companies via ads in the computer rags.

  83. War Puppy

    I was given a ZX81 as pay for my 1st ever dev job that was developed on my ZX80 (paid for through much wrinkled skin, car washing my weekends away).

    Basically my dad was a Quantity Surveyor, barely using a calculator (up from slide rule) and I wrote some code to work up costing for a building after inputting some basic data. From an hour down to 10 minutes.

    We went into his work, where slack jawed Neanderthals witnessed the future as I priced up a drawing in 10 minutes, that their best took 40 minutes over.

    I do miss the days of wonder, as 'new tech' appeared weekly or monthly in magazines, I had to travel on a 1 hour bus to buy.

  84. russmichaels

    amazing that this thing actually had a 3mhz processor but was so limited and rubbish. To think the C64, the best home computer of all time, only had a 1mhz processor, yet was a 1000 x better.

    1. This post has been deleted by its author

    2. Andy3

      Yes, but there was a rather large price difference!

  85. Chris Johnson 1

    Capable of so much more

    My first outing with the ZX81 involved developing a new ROM for it to allow it to function as an assembler development station (ZX ASZMIC). Its biggest problem was the absence of dot-addressable graphics but by shorting out two lines on the rampack connector (others used diodes but these were not actually necessary). Once that was done you could have new character sets which included lower case and, by stealing the stack address used by the command interpreter, introduce exciting new commands for it. I had everything from line drawing commands to sprites and even windowing like that new-fangled Lisa computer. Fortune was assured, and then evil Clive introduced the Spectrum with colour and killed the ZX81 market :-(

  86. andyL71

    Say to Thorin "carry me"

    I saw my first computer in 1981 at primary school, when they were brought round for the kids to look at as part of a national programme. I was captivated and spent the next 2 years drooling over computer magazines, code listings etc. Every small town in the UK seemed to have its own computer shop and every time my folks took us on a day trip I would find myself with my nose pressed against a window, speculating on the relative merits of Dragon 32, Vic 20, and Spectrum.

    Spectrum won out, and I loved it. Perhaps not the highest level of quality - 6 passed through my hands in the early months of 1983 (including 2 in one day). It absolutely led to my career in IT, and Speccy No. 6 sits in a cupboard behind me as I write this.

    I won a modem for it in a Blue Peter competition, along with a year's subscription to Prestel, which I used for a space MMO and my dad used for Bank of Scotland Home Banking. This was around the time of the Duke of Edinburgh hacking scandal.

    From the code listings in magazines like Computer and Video Games and a bit of graph paper I figured out how to create and move 8 bit sprites. I sometimes wonder if programming a sprite of a helicopter to buzz over the screen and fire a missile at a sprite of a tank might be the best thing I have ever achieved in IT.

  87. Gordon 8


    I had a new ROM ZX80, and then a ZX81.....

    It was passed on to someone else when I got a Commodore 64....

    However at a Radio Rally in the early 90's I saw one with an original RAM pack for 5 Pounds

    I Still have it and last time I checked it works. I even brought it 8,000 miles to Singapore.

    I don't have a TV that works with it any more.... My Flashy Samsung thing does not seem to work with it.

    Beer for Sir Clive...

    Mine's the coat with the pocket large enough for a Zx81....

  88. Anonymous South African Coward Bronze badge

    How long till we do the 48k Speccy's 37th anniversary?

    1. Anonymous Coward
      Anonymous Coward

      The speccy is 36 years old in April this year.

      You can order a future-proofed for another few decades version from

  89. Andy3

    Oh gosh, what memories! I bought one in 1981 and proceeded to teach myself Sinclair Basic. I was enthralled by the feeling of control, the way I could change a line of Basic and make different things happen. Before too long I was writing simple games like reaction timers and even a (rather slow-running) shooting game. We later got a BBC-B and that was a speed-monster compared to the Sinclair and I even managed to write a weather-fax decoder for it, all in BBC Basic. Happy days, and all in just 1k for the Sinclair and 32k for the Beeb! We've still got the BBC (and it still works), but I really wish we'd kept the Sinclair.

  90. Badgerxx

    Wireless ZX81

    My local radio station (Pennine Radio) in Bradford had a computer show where us budding geeks and nerds could post in cassette tapes of our latest lunar lander or bubble sort programmes for broadcast over the airwaves. Fellow geeks could tape the whistles and beeps and share in each other's creativity without ever having the meet in person or speak to each other on the CB radio! Happy days.

  91. Umpty Numpty

    Space Invaders

    May only be 1024 characters, but it took a bit of typing in in Assy

  92. Munkstar


    Got bored very quickly waited for the iPhone.

  93. StorageCamel

    ZX81 vs Atari 2600

    I had a ZX81 and later got the Sinclair 16KB RAM pack...the wobbly one.

    Missile Command was pretty easy to program on the ZX81, even in basic.

    Back then I showed it off to a friend of mine who had the Atari 2600. Apart from the colors and sound it looked like the real thing. That was until I got the Atari600XL of course.

    My main issue was that the off-the-shelf portable cassette player ( I think Panasonic) did only load the games once in a dozen times, despite me endlessly fiddling around with the volume.

  94. Curator

    My first computer and the start of a 30 year career in IT. If anyone wants to have a play on one, we have a working one at the Museum of Computing in Swindon.

  95. unwarranted triumphalism

    Still a better computer that anything by crApple.

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