back to article Remembering the Commodore PET 2001

Bah. Kids today with their Nintendo Wiis, iMacs, 30-inch HDMI screens, PDAs and CD-Romses. This old box logo Back in the Golden Years of electronics, personal computers required a Master's degree or a crippling social disorder to operate and it was better that way. And colors? You had two options: stunning beige or get the …


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  1. Danny


    I remember some of the older geezers (the real UNIX grey beards) reminiscing over the PET when the Amiga was still king. They had fond memories. I was a bit too young at the time and was still drooling over Princess Leia (or was it R2D2) at the time. I love the Deep Thought photo.

    A built-in cassette deck? How modern. Clearly Commodore didn't want any of this mucking around with cassette leads like we had to with the Speccy. It wasn't until the CPC when Sir Alan slapped a deck onto the side of his carbuncle.

    I still have a Tatung Einstein and several Speccys and ZX81s around somewhere. The Amigas are still a joy to use. Doing stuff the upstarts of today can only dream about. Linux is the closest I'll ever get to the robustness and flexibility of the Amiga...

    When I were a lad we used to 'ave to squeeze subroutine in't 100 bytes, graphics, sound an all, using hand crafted assembler, an't use ROM image for random numbers. And still have bytes left. Try you try telling that to the kids of today... and they won't belief you.

  2. Charles


    Wow, that's a blast of nostalgia. I remember writing accounting software for the PET. We wrote in UCSD Pascal on Apple II computers, it was easy to port to other UCSD platforms. We wrote once and recompiled for use on the PET, Ohio Scientific, and a few other obscure platforms (none of them over 2MHz, ha). The Apple version was the only software that ever shipped.

    But really now, you should have asked if you could open up the PET and taken a pic of the insides. IIRC it was mostly a big, empty plastic box with a little motherboard at the bottom. The top part was hinged at the back, you raised it up like the hood of a car, it even had a little rod to prop up the top.

  3. Chris Stephens

    PET Game emulator

    There are PET game emulators out there. Even one that runs on a xbox.

  4. Anonymous Coward

    I wanted one sooooo bad....

    I thought it was the coolest looking damn thing ever. It was the only thing that was self-contained in a case. Everything else had a tape deck over here, a monitor over there, a keyboard somewhere else, and maybe the motherboard laying bare on the table.

    Instead I got stuck with a TRS-80 Model I with 4K of RAM. I remember the upgrade to 16K was $220, and my mother said I didn't need it because her IBM 360 mainframe only had 16K. (yup, my mum taught me to flowchart)

    But hey, that was still more computer than my high school had.


  5. wobbly1

    The first time i knowingly used a microsoft product....

    I worked for one of the first UK Commodore dealers before the ad. campaign started,so spent about 3 months with a pair of pet 2001's, The earliest models had the equivalent of bonnet stay , so you could prop the top up while you worked on it . Chip creep was a frequent problem on the few socketed components...

    The machinations of the demon Gates could be revealed by typing "wait 6502,0" and the screen filled Yahoo! Style! with "microsoft!" 6502 being the cpu designation.

    AS a dyslexic with a 4 chr corrupting buffer , being able to enter BASIC instructions by typing the first 2 chrs of the instruction and shifting the second character, gave me a way in to programming.

  6. Josh


    Did anyone try overclocking the PET? Did they get it over 5 MHz?

  7. Anonymous Coward

    I sold these in Tottenham Court Road in 1978

    together with the early Apple ][ (pre Apple Disk Drive Apple used a standard audio external cassette recorder) and other assorted boxes.....those were the days.

    To those who want to travel down memory lane.....

    CBM - PET

    Apple ][


    BBC Micro




    Sinclair ZX-80/ZX-81 and then the one theat broke it all open the Spectrum

    I remember them all well........

  8. Peter


    Why would you need to? Everything ran like a dream.

    As it did with the speccy, the CPC's....

    Hell pretty much everything prior to the 8088, and even most of the x86 line stuff was fine until Windows 3.0 hit critical mass....

  9. Nick Ryan Silver badge

    Re: Overclocking

    I don't remember overclocking really being such a thing in those days - mainly, I believe, because everything was so tightly coupled that "overclocking" generally meant running *everything* faster, and this was usually rather problematic and pointless as 10% faster graphics output just meant nothing would be displayed on screen.

    Also, with no decent timers available, time sensitive code was coded by hand in assembler and, because of the additional delay in branching over memory pages, carefully locked in certain locations in memory. The sheer joy of writing loop and branch code that executed in exactly the same number of cycles every time was just *such* fun...

    These days, most developers would look at you blankly if you pointed out the extra 5,000 clock cycles (or whatever) they waste every time they make a call to COM. Their usual optimisation method is to "use faster hardware"

  10. dek

    ahhhh yes...

    I remember the sore fingers after a few hour use! The second computer I ever used.

    PS: Did it run Linux ;-)

  11. Alan Potter

    Byte shop anyone?

    This really does take me back. I worked in the Byte Shop in Gants Hill the day after it opened in 1977 (I think). We sold the Pet 2001, The Cromemco Z2D, the North Star Horizon,the Kim 1, the Sim 1 and the Nascom. If I remember rightly, the Pet sold for £795 originally, though I think that was the 8k model. Eeeh, those were the days...

    @Anonymouse coward who sold Pets in TCR - can you remember (are you willing to name) the computer shop you worked in?

  12. Robert Long

    Loved it

    Had one (8K) and loved it. I learnt how to program from the manual, although assembler eluded me until the Speccy came along.

    The motherboard had 5 6502s, I think, and at least one of them could be taken out with no visible effect on the machine's performance (I think it probably controled the edge-connector I/O which as a kid I didn't use much).

  13. Rob
    Thumb Up

    I've still got

    two of the 8000 series (a square edged one and the later round edged model) along with a dual disk drive. I should probably try to flog them - they're not doing much good stuck in the attic!

  14. Jon Double Nice
    Thumb Up

    DRAGON 32!!!!

    man I loved that thing. 'Juxtaposition' was the most amazing game for quite some time.

  15. Garry Mills

    Learnt to type on one of those

    We had one in my secondary school which was so well used the decals had come off all the keys, so unless you fancied stabbing away for hours producing gibberish, you had to learn the QWERTY layout PDQ.

    Sharp learnt a lot from these with their MZ-80A's


  16. Alan Potter
    Paris Hilton

    I'd forgotten the MZ-80a!

    That was a pretty cool machine if I remember rightly. At the Byte Shop we also got the first Compucolor in the country. I remember getting very excited about it because it was the first colour CP/M machine. It arrived at something like 8 at night. It had an American plug so we cut that off, stripped the wires, put it in a safety block, turned it on... And BANG!!! Yes - in our excitement we hadn't thought - American plug - American voltage/wattage? It had blown the main transformer. Our boss was not best pleased.

    I also once had a guy in the shop threaten me with two nasty dogs when I refused to accept back Trash-80 memory from us because he'd bent the legs inserting them. SIMMs are for poofs...

    Oh - and I've chosen the Hilton icon, not because there's any Hilton angle here, more that it's the only one that shows someone shedding a tear and with all the nostalgia here, that's what I'm doing... <sniff sniff>

  17. Mike

    Byte Shop Gants Hill

    Now that brings back memories of when a few of us kids would pile down there after school to play on PETs and Cromenco Z2 (?) rack based CP/M boxes (with their 8" disc drives..).

  18. IanKRolfe

    @Alan Potter

    I lived in Billericay and used to pop on the train and go to the Byte Shop every now and then. The staff there (was that you??) were quite understanding and let you play on the shop computer (for a while...) and I typed in several of the programs I wrote at school into the shop pets and got them running. I even bought a blank cassette from you and saved my programs too!

    Eventually I persuaded my Dad that he needed one for his business and we got a "Grey Import" (complete with 250v-120v transformer!) PET that eventually got upgraded to 32K and my dad used to run his upholstery business with software I wrote for him. I still have that PET, and another 4032 PET I bought a few years ago unworking that I am fixing up.

    @Robert Long - The pet had only one 6502. It had a 6522 VIA and two 6520 PIA i/o chips, which would come out if you didn't need them. I managed to blow up the 6522 while experimenting with connecting a paper tape reader and had to replace it.

  19. Jon Axtell

    Egg advert

    I bet anyone whose remotely geeky has seen the Egg adverts with the hamsters and will have noticed the Pet in one of them. The other advert has the Tandy TRS-80. My wife definately thought I was a geek when I noticed the computers and could identify them! ;-)

    I remember using the Pet when I was in 6th form. I also worked on a product for pharmcists that would run on the Tandy TRS-80. Ahh, great times then. :-)

    Can't wait for the Sharp MZ-80K to be featured. I've still got mine in the attic!

  20. This post has been deleted by its author

  21. Madge Silver badge

    My memories

    Computers in order of use (most of these at home apart from mainframes)

    Mainframe at QUB: Handwritten QUBOL

    ICL running George: Fortran, via punched cards.

    SC/MP: Assembler

    Z80 board I designed running Assember

    Apple ][ with Z80 card for CP/M. UCSD pascal. Upgrades: 5MB HD, 1M dual8" floppies.

    ACT Sirius I: CP/M 86 & MS DOS. 800x 400 graphics & 2MByte variable speed floppies

    IBM XT

    Intel 8080 dev system with Cartridge Winchester and ISIS II OS

    Apricot with MSDOS 2.11 and then 3.3

    Cromenco Z80/68K with Cromix "UNIX" like OS


    Jupiter Ace

    Amstrad PCW8256 with RAM and 3.5" PC disk upgrades

    IBM AT

    WANG 80286 (not PC) with DR-MULTIDOS running Win3.0

    Horizon Multiuser system (PC cards with Composite Video out in main box, shared disk and keyboard, screen, etc via multicore cable)

    Wang 286 PCs with Win3.11 on DR-DOS

    Wang 286 running Minix

    Various clone PCs with WFWG3.11 and Network

    386 running OS/2 Warp, recycled to NT3.1

    AST 386-33MHZ, 12M RAM running NT3.51 server!

    Various 486s with NT4.0,


    Various 586/Pentium class with NT4.0

    (older PCs installed with mix of Win95 and Win98 SE for games).

    HP laptop + NT4.0

    RH6.0 Linux on various 486/686 (1999?)

    Pair of old AST dual CPU Servers (P-Pro?) converted to MS Cluster with 2 shelves of 8 x SCSI drives. AMI controllers. Just after 1st release of NT4.0 Enterprise Server.

    Atari ST

    Dell Inspiron 7500 + NT4.0

    April 2002 XP on Inspiron 8200, still great today.

  22. Giles Jones Gold badge


    I wanted one of these when collecting computers a while ago, couldn't find an affordable one.

    I remember seeing Fraggle Rock and the lighthouse keeper had one.

  23. Matt


    Try this site for looking-up your favourite old computers...

    Mine? My first, the classic Sinclair ZX-81, still in the cupboard, but broken...

  24. Alan Potter

    More about memory

    But first: @IanKRolfe - It may well have been me. I wasn't the manager (I was too young) but I was trainee manager. I used to bunk off from school - Ilford County High (bloody hell, this is beginning to sound like Friends Reunited!) to work there. The manager was Vince Cohen.

    I blagged my way into the shop and was hired as halfway between a shop assistant and a bouncer. Frequently I would still have my blazer on...

    I really feel that, as these sad revelations are springing forth I should leave.

    Yes, mine's that white one over there with sown-up sleeves that do up round the back. Thanks.

  25. vincent himpe

    aah . the memories

    having to program in a real mens computer language : assembly.

    last week i had a nasty surprise : void main void { while (1) x=x +1; } on a risc machine .. 3.6 kilobytes of ROM code !. with all optimizers switched on : 92 bytes of code... in machine language : 2 instructions : INCR ACC , CLR PC

    talk about bloatware these days ... c compilers ... i want my PL/M compiler back

  26. Anonymous Coward


    That's such a familar list :)

    Sure there wasn't an RML 380Z in there as well?

  27. Gerald Davison
    Thumb Up

    Got one!

    This was my first "computer". I bought one with my then life savings of £400-00 (a hell of a lot of money in the late 1970's). I was only 14 at the time. I think it came from a shop in Liverpool called DAMS Office Supplies???

    The tiny keyboard was a pain to use, but you got used to it.

    I was doing Electronics at "O" level at the time and I upgraded the RAM myself from 4K to 8K. I had to de-solder the old chips and replace. Somewhat heart stopping, but it worked.

    I also built a Joystick using an Atari one as a basis. Worked a treat!

    Final project was to to connect it to a second hand 110baud teletype to act as a printer - I built my own 20mA current loop interface and wrote the machine code to drive it.

    Ah, happy days!

    Stood me in good stead, 30 years later I'm still working in IT.

    By the way, I've never been able to part with it, it's in my attic gathering dust.

  28. Martin Gregorie

    For those of you pining for a simple life...

    If you'd like to hack round with close-to-the-metal computing again, take a look at the Parallax STAMP. Its a tiny motherboard that fits a 24 pin DIP socket. You program it in integer BASIC and it has 16 i/o pins which can all be used for digital i/o or as ADCII lines. It will do about anything you can imagine provided you can fit it into 2K of EEPROM and 32 bytes of RAM.

    See or in the UK if you'd like to play.

    Continuing the original theme, my first computer was a self-assembled SS-50 system from Brian Hewart. It had a 2 MHz 6809 for power and ran Flex-09 off twin floppies. I soldered it together and then debugged the hardware with a logic probe and multimeter. It was programmed in assembler, BASIC, C or (the best) PL/9, which is based on PL/M. It still runs, though its now in a different chassis with 4 floppies, an 80 x 25 screen (originally 64 x 16) and a whole 48 K RAM. The change in screen format required a complete ROM rewrite, but that was no problem as I had an EPROM burner in it as well.

    From there I moved to OS-9 on a 68020 and then Linux. Needless to say DOS, 'doze and Borland C was there in the background for work compatibility.

    I hope El Reg keeps this series going, but as well as classic hardware, it would be nice to cover the pre-1981 operating systems: CP/M, Concurrent CP/M, DR-DOS, the UCSD p-system, Flex 2 & 9 and OS-9 to mention the main ones.

  29. Adam Williamson

    still got one

    My family still has one of these hanging around in the cellar, I think (unless they threw it out since I moved). Tape drive hasn't worked for a few years, though.

  30. Simon Redding

    Music to my ears

    After learning to program on a KIM-1, this was paradise. No more hex operands...

    I spent a few good years programming these - they got quite good with the 2048 etc.

    The highlight for me was getting software to run on the embedded 6502 controller in the external SCSI hard disk drive and banging the heads with varied delays to make music. Needless to say it wasn't my system...

  31. David Heys

    My first job was with a PET

    Started my software career with one of these things. I worked for a software house called Stage One and helped write database software (PetAid) that worked with twin cassette decks and later 5¼" floppies! How DID we fit all that in such a small amout of RAM? Great stuff!

  32. Bas Wientjes
    Thumb Up

    Ah, fond memories indeed...

    In fact, it was my very first computer to play with and I actually still have it (in working order)! Mind you - it's the later 8KB model with the full size keyboard and external tape drive.

  33. Martin Beckett Silver badge

    For real retro addicts Expect funny looks from wife if reading it in bed!

  34. Anonymous Coward
    Anonymous Coward


    I had use of a PET as my first computer. (My dad was the deputy head of a high school, so brought computers home at the weekend) I remember it well, especially the the ridiculously dangerous power supply that gave you shocks if you touched the live a neutral of the plug up to ten mins after you'd unplugged it! Having said that my fave bit about it was the car bonnet style rod that kept the monitor section up when you had it open, genius.

    I'm still after one for my old computers collection. Having said that, it was quickly superseded when my mum and dad got a BBC Master 128 with _all_ the trimmings - InterWord ROM, 3.5" and 5.25" FDDs, Acorn Music 500 (ROCK!!!!) Panasonic KXP1081 printer and a Microvitec Metal box CUB monitor - for about six months it also had the 80186 (!?) board. I've got a serial cable that I can up and download disk images to/from my server, but I'm working on getting an Econet to connect to my Archimedes, then ethernet to my Server, I'd like to see someone hack that! (I am under no illusions that "it'll never work" TM)

  35. MondoMan

    Exidy ruled!

    We Exidy Sorcerer owners were secure in the superiority of our "real" keyboard and 30x64 character display...

  36. Steven Moore
    Thumb Up

    Thanks for the Memories!

    I bought a PET in 1979. Cost me about $1000 (US). 14K ROM and 8K memory (the OS used the first 1K).

    I did my first serious programming on that machine: a DBM (in BASIC!) for a study I was doing where I worked. I remember a LOT of reads & writes to/from the cassette for that one.

    The Assembler for that was a lot of fun, too.

    Memories. Sometimes wish I still had that box.

  37. Anonymous Coward


    Maybe age has dimmed your memory somewhat. The Amiga was a wonderful machine, but robust? It had no memory protection, a single null pointer deref could take it down in a steaming heap of guru meditation. Yes, it had proper pre-emptive multitasking (unlike MacOS/various MS efforts) but could still be taken down instantly by the most trivial bug in a program.

  38. BitTwister

    @Martin Gregorie

    > Continuing the original theme, my first computer was a self-assembled SS-50 system from Brian Hewart.

    Ah, nostalgia. What a blast from the past!

    My first computer was also from Brian Hewart (where is he now?), a self-assembled 6800 system on a rather large PCB - don't remember the model number, but AFAIR it did work first time. I later graduated to a self-assembled Nascom II and things really started taking off. <sigh> Miss those days of hacking Z80 binary code... (and I will be having a look at the Parallax STAMP!)

  39. Steve Scott
    Thumb Up

    good memories

    The PET was the first computer I ever used, and it was regarded as a powerful and mysterious thing in school! Only 6th formers had access to it, and the A key was kinda worn out (primarily because it was the fire key for the Space Invaders game!) I recall it had twin external floppy disk drives (5.25") and you had to type >$0 for a directory listing.

    I used to buy PCW magazine which had program listings, and I'd spend hours typing them in, only to find they wouldn't work... assuming I'd made a typo, I'd spend hours going through the listing again and again, and eventually give up, and then the following month the magazine would publish a correction to the listing....!

    Pokes and peeks... ahh happy days.

  40. Ian Ferguson
    Thumb Up


    Although the Acorn Electron was the first machine I learnt to program (or programme as it was known in those days), I still have respect for the PET - a design classic. Storage, keyboard, CPU and screen all in one neat unit? Funny how things come around!

    Ooh, I do hope this series touches on the BBC B micro - not the earliest or the most powerful of its time, but the first computer of the people most certainly, and the BBC Basic language truly a beauty to behold (the astonishingly well written manual is still on my bookcase, and I still occasionally flick through it with glee, much to the disgust of others)

  41. Matt

    Ouch, now we're going back.

    I remember the Vic 20, BBC and I learnt to program on each of them.

    But this was before I was born.

  42. Martin Huizing

    Wake me up...

    ...when you re-review the TRS-80. The first computer my mother bought me for Christmas. Green glowing screen, clickety keyboard, tape deck I used later for my Toshiba MSX-1 and the first computer I blew-up! Ah.. Nostalgia galore!

  43. Terrence Bayrock

    No wimpy programming allowed here !!!

    Cut my teeth on an early PET 2001; Graduated to a C64 with a floppy drive!!!

    Toughest assignment: design a game that the player CANNOT LOSE without it being overly obvious. Done for an electronic shop intent on giving away "freebie" merchandise for promotional purposes.

    Went with a "find the buried treasure" approach.

    Didn't want to board the ship? You were plied into service in the best of Her Majesty's traditions by the "gang".............

    Didn't want to navigate towards the Island? A hurricane "miraculously" appeared to whisk you on the way...

    Couldn't walk to the treasure? A local earthquake can help you with that....

    Etc etc.

    Jolly good fun (if you pardon the pun) and all done on a base model C64, full graphics, joystick and on a large tv for all to see.

    Now I'm in management with my memories... sigh.......

  44. John Helliwell

    dot co dot uk

    Colors? Honor? Ewww.

    Anyway, you could overclock the Dragon 32! I remember you could poke (oo-er) a value into a hardware register and it would change the clock-speed of the Motorola 6809 CPU. You could overclock the machine so much the SAM chip would lose synchronisation and the display would scramble.

  45. Rob Beard
    Thumb Up

    That takes me back

    That takes me back, not to the early 80's but the early 90's. We had one of these machines at secondary school in the CDT department. The teacher explained a bit about it and we got to see the insides too (I always thought the car bonnet type opening was added by my teacher!). Being a true geek I was fascinated by the machine.

    I'm really looking forward to the next article. My first computer was a ZX81 when I was about 5 and it was fairly old then.

    I'm now trying to make a collection of retro machines, so far I've managed to pick up a Vic20, Acorn Electron, Spectrum + and only yesterday I picked up a Dragon 32 which I'm looking forward to playing with.

    As much as I love emulation, it just isn't the same as actually using the original machines. :-)


  46. Andy Enderby
    Thumb Up


    I remember passing my O' Level Computer Science on the back of programming projects completed on one of these Commodore PET's. I was one of the second intake inour school to study computing of any description, and one of the first three students offered the O' Level qualification when our tutor was supposed ot take his. Bless the guy, whilst we three all passed ours, juggling his job and family had an impact on our dear old tutor, as he failed his on the first time of asking, whilst managing ot get enough knowledge into us to pass. These days he wouldn't have been permitted to attempt such a stunt unless he had passed the exam first....

  47. Alan Potter

    Sorry to keep posting to this thread...

    ...but it fair warms the cockles of my heart - or something like that.

    Anyway - I got caught bunking off on more than one occasion from the sixth form to work in the Byte Shop. Eventually I had to go and see the headmaster. He told me to stop wasting my time and that "Microcomputers are a passing fad like hula-hoops and skateboards."

    He always was a visionary. I'd like to say something like "he now works for Apple" but I can't because he's dead.

  48. Dave Lawton



    Why don't you just add an ethernet card to your Arc ?

  49. Anonymous Coward

    PET - the last good computer Commodore ever made*

    * I'm lying, Commodore have never made a decent 'puter.

  50. Anonymous Coward


    Awww, now you've made me go all misty-eyed. Those truly were the days. ZX81. Acorn Electron. Vic20. PET. Apple ][. BBC Micro. The excitement of colour, and sound, for the first time. *sigh*.

  51. Gareth Morgan

    Real computers

    I started with a Northstar and then moved onto a Superbrain - with *two* floppy drives (and an unfortunate experience with a Gemini S100 machine).

    We laughed scornfully at Pet owners as we spent hours trying to work out the cabling for RS232 dot-matrix printers. No games for us (except Zork of course), we were running social security calculations written in Z80 Cobol.

  52. John Colby

    Ah! The old days ...

    And nostalgia isn't what it used to be, either.

    But being serious, I'm currently writing a degree level course part that has to use the command line - what I take for granted I'm having to explain in great detail. And I;im sure that I'm missing a load of things that I'll have to explain in greater detail.

  53. Anonymous Coward

    I feel old

    I use to dream of having a Commodore Pet but we could not afford it and my dad bought a Video Genie (TRS-80 rip-off) which was my first real intro into computers and programming. I loved that machine to-bits and it is was amazing what you could do with a small amount of RAM.... I feel that some programmers today could learn a lot about how to write good, tight, efficient programs or maybe I am just getting old....

  54. Simon Harris

    Ahhhh nostalgia...

    ... just the mention of those part numbers starting 65... brings back happy memories.

    First computer I learned to program on was a PDP8e that we had at school, followed by a SWTPC 6800 system with Flex (ahhh, the days of the +++ prompt).

    The first computer I owned was an Acorn Atom, 1MHz 6502 with 12K RAM. Didn't stay 1MHz for long since I found I could overclock the processor to 2MHz, although the RAM was nominally 650ns 2114s, so I had to swap them all around until the ones that couldn't cope with the exrta speed were at the bottom of the display memory.

    Back in those days it was fun trying find ways of squeezing as much as possible into that amount of memory. Life just doesn't have the same challenge with 2GB to play with, and I haven't touched assembly code on a PC in about 4 years.

    When I want the fun of the old days, I get out my PIC development board and see just how much I can do in 2K of assembly language on the thing.

  55. Anonymous Coward
    Anonymous Coward

    @Dave Lawton

    That's what I meant - stick an ethernet card in the Arc and use it as a bridge. Like I say, it'll never never work, but that hasn't stopped me hitting Ebay hard for the bits that I need...

  56. Anonymous Coward
    Thumb Up

    Re:Overclocking - ZX81

    The ZX81 had two modes, FAST and SLOW, unfortunately in FAST mode you lost the display. By switching modes at an appropriate rate you could get a tune out of the TV.. 16 whole K of memory. My still working ZX81 still boots in under two seconds, somewhere it all went horribly wrong..

  57. Anonymous Coward
    Paris Hilton

    Still alive

    The college I went to, in the mid-1990s, had one sitting near the entrance of the computer department. The man in charge was wont to say that it was the most expensive machine in the room, which was otherwise filled with Apple Macintoshes. It was a later model PET, with a proper keyboard, and it still worked. In fact it felt indestructable, and I expect it still works today. When we're dying it will be still alive. When we're dead it will be still alive.

    I choose Paris Hilton as my avatar, because she also only has a tiny amount of processing power.

  58. Stuart Halliday

    How to destroy a PET

    Did you know the PET was probably the only computer you could down by writing a BASIC program?

    There was a certain poke command you could do which shorted the 5v line and eventually caused the power supply to shut down.

    Oh how we would enter a computer shop (not many back then), enter a quick program with a suitable delay and stand outside the shop watching the computer go off. he he.

    Happy hacking days....

  59. Simon Harris

    @Stuart Halliday - blowing things up from BASIC

    Seem to remember Monochrome IBM PC monitors were quite prone to blowing if they got the wrong line sync frequency.

    Once upon a time I hit the 6845 video controller timing registers with a few OUT instructions from BASIC (I think it was on a Hercules graphics card rather than the original text-only display card), pushed up the line sync rate, got a high pitched squeal out of the monitor and blew the horizontal scanning circuits.

    The flame icon seems appropriate in the circumstances.

  60. Graham Lockley

    You cynical bastards !

    I can see the editorial meeting:

    ' OK so we chuck out a few cheap and cheerful articles about a few old computers and let the greybeards fill a few pages with 'When I were a lad' responses'

    Shame on you El Reg, such cynical manipulation of a large portion of your readership !

    Mind you, if the Dragon 32 makes the list .....


  61. William Higinbotham


    I remember at the time the different magazines such as Byte. They had articles on most of the platforms. It was interesting to see what the other brand users where doing with their computers.

    Billy Higinbotham, Bellport, NY

    The ASCI guy

  62. Anonymous Coward

    @ Alan Potter

    The shop i worked in in TCR was Eurocalc (about half way up on the right - I think it's a Carphone Warehouse now?).

    Here's one that will throw many people - the ITT 2020, Apple licenced the Apple ][ to ITT (mainly because Apple couldn't make enough of them) and ITT botched it by having an extra bit in the graphics output, consequently in grahics mode every 8th pixel was a solid vertical line - also it was a really cheap looking silver/grey colour (although the same case design as the standard Apple ][).

    In those days TCR was run by The NLJM (Loretta Cohen out of Lion House, Peter Ingoldby owned Eurocalc - et al)'s now run by SEAM......good days though.

    Reading this thread gives me a desperate need to type in a Yorkshire accent for some reason?

  63. Anonymous Coward

    re: Stuart Haliday

    FYI, the command was "poke59458,62", and it didn't short the 5V line (as it would be pretty hard to do that from software) This command would speed up the display on older machines--don't remember the tech details, but you can probably Google it--think it had something to do with fooling the display not to wait for the CPU. Newer machines with the larger monitor ("fat 40" they were sometimes called) had a CRT controller chip. Poking to this location on these machines would cause the equivalent of turning the refresh rate too high on a modern monitor, and CRTs with weak flybacks could be made to smoke and die. And also, as someone else mentioned, this did NOT have several 6502s, just one. It had several 6522s (VIAs--versatile interface adapters) which provided many IO functions that were pretty far ahead of their time. (and the 8050 floppy drive could store half a meg per side of a 5 1/4 floppy--not too bad for 1979--you could also issue the drive a command to format a disk or copy one disk to another, turn off the computer and walk away--the drive had its own 6502 and OS)

  64. John Benson

    bloatware: an epiphany

    The coin finally dropped while reading the posting about a tiny endless loop that ran till overflowing a counter:

    A classic optimization is loop unrolling, in which loop code is repeated in many juxtaposed sets of mostly the same instructions. This technique minimizes the test-and-branch-if-... logic and probably allows peephole optimization much wider scope to work in the unrolled loop than in the direct and obvious translation of the loop with one test/branch sequence each time through the loop.

    I have been reading, and sympathizing with, complaints about bloatware for years, but nobody has ever provided any figures about how much bloat comes from aggressive loop-unrolling versus featuritis, so I'm going to get off my bloatware soapbox until I hear from the experts.

    Are there any out there that care to chime in? (Quantitative data earnestly desired.)

  65. John Duke
    Thumb Up

    Thanks for the memory.

    Still got this one, After reading the article , I convinced my Pops to pull it out of the attic, and take some pics,. - The thing still works , but the tape deck is pooched, we think the drive belt has decayed. The only other problem is the *A* key which was the fire button in 'Commodore Invaders' , might have taken a bit of a beating :) .- Learnt to program on this baby, and realized there is life for a social retard, been with computers ever since and liking it very much thank you !. I remember when we had this I bragged about it at school, got called a liar by my teacher Mr. Jenkins , So I sneaked the manual to school to show everyone, and got a break time detention for being a smart ass.- all at the tender age of 7, Ahh the happiest days of our lives !!

  66. dennis


    I am 30, I was programming at 5. say no more...

    ok I will then. By the time I was 10, I had tried nearly 95% of the available machines on the market, Spectrum, Texas 80 (TRS80), Commodore, Dragon 32 and 64 and prototype 128 just before they went bust (again), Amstrad CPC (all 4 models), EINSTIN (This was a fantastically advanced machine, so much so they went bust in development and just couldn't afford a launch for a product 3 times more expensive than the next best toy on the market, but at the time nothing else would allow you to edit the software while it was running in the background and still allow a second process to be started. I remember the OIRC? and MSX designed machine (the Idea with MSX was to allow people to design there own machine and so long as it met certain design spec all applications would run on it)

    I the Dragon 64 1st edition was made on the cheap, by piggybacking memory on top of other memory to double up on it, with a small switching circuit to flip between the 2 quickly (in usage) this was to stop people from rejecting there product when everyone else had 64k or 128k machines out there. later models had proper memory design, but having 2 different machines with 64k memory did lead to some software issues, and some times the machine wouldn't run big software packages like 'sprite' etc without a 'poke' entered before running it, fortunately they only had about 1000 machines with this problem. I remember most (nearly all) games were microsoft, and the basic OS was microsoft, and when loading many games there was a 4bit colour image of gates himself to look at while you made tea and waited for the games to load.


    take me back any day. :)

  67. Anonymous Coward
    Anonymous Coward

    Why this didn't sell well in Germany...

    I heard that this did not sell very well in Germany becuase 'PET' meant something else in German. But Commodore did not learn from their mistake and named the next model 'vic' which when pronounced in German sounds like an even ruder word!

  68. Anonymous Coward
    Anonymous Coward

    My first large program was on a PET

    My father ran a hotel business and had a staff payroll of about 25 people to do every week. It took him ages looking up all the tax tables and filling in the accountys sheets. I said I would computerise it for him if he bought me a PET and he did. I was only a teenager at the time.

    The program worked well (but took ages to load). I had to EXACTLY match the tax tables (including rounding down in exactly the same way as the goverment did) so that the end result exactly matched the manual calculations he did. After a month, my father just used my system and it took him 30 minutes rather than 3 hours!

    Only problem was he did not want me to use the PET after that in case I mucked it up!


  69. MaNIaC

    All our yesterdays

    Didn’t the PET have Micro$oft Basic, complete with garbage collector bug, no change there then, whatever happened to them!! I upgraded from a UK101 kit to the PET and spent many a happy hour under the hood learning 6502 assembler and burning eproms. Oh to be young again *sigh*

  70. Alan Potter

    I feel bad about continuing this thread, but...

    @Anonymous coward - I think it's likely that we worked opposite each other. What's more, I then moved over the road, as it were...

    If only we could communicate directly...

  71. Simon Millard
    Thumb Up

    Those were the days

    I learnt to program in Basic and Comal on one of these beauties when I did my YTS at Portsmouth ITeC.

    It had a IEEE488 bus with 5¼" disk drive.

    I wrote a snazzy, text graphical, fruit machine simulator with it

    Tho' if you hit return at the READY. form, it did throw a "Can't read Y." error message.


  72. James Summerson

    Oh, the humanity!

    I'm with Steve Scott in that I also spent very many hours back in the late 70s typing listings into our school PET from magazines. The only ones that worked first time were a 'Jumbo Jet Simulator', which was a dot on the screen(!) which you had to keep on a downward flight path and a fantasy RPG which was called something like 'The Tower and The Valley'.

    Ah, happy days! I'm waiting for the Spectrum, Dragon and Atari ST articles...

  73. triky

    too young too remember but not too old to care

    i'm no tecchie (wordsmithing's my game) but yeah, that machine makes great sounds ! i got an emulator and dled some funny files that makes all the original sounds from that machine. ideal for chip tunes ! viva el commodore! and thanks to 8 bit weapon for the fantastic idea :D i do love those sounds...

  74. Tony Bryer

    And only £1000 (+cassette recorder)

    My software business's roots are with a PET: I took out a bank loan to buy one of the first 32K large keyboard models, and the program which has earned me good money since 1989 was first written on my PET (then moved to BBC then PC). Back c.1980 the UK Commodore Users Group used to send out magazines with code listings printed (IIRC) black on green - perhaps the world's first copy protected software!

  75. Neil Barnes Silver badge

    Tsk, computers in boxes?

    You're all soft - real men used stuff on PCBs with dodgy power supplies and bolted on expansions.

    Bring back the MK14 and the Tangerine!

  76. Steve

    Re: ITT 2020

    It wasn't botched, it was a "europeanised' Apple ][

    The extra memory bit was added deliberately, I think for the 60Hz/50Hz frame difference between US and Europe so UK-spec displays could be used. There was extra RAM added for the extra bit required, but it was 'on the end' of the display space. Official ITT software, and things which didn't bypass the monitor (the BIOS, for the youngsters), worked fine. It was the Apple-specific programs, especially those which wrote directly to video RAM, which had every 9th bit blank. I vaguely remember at least one chess program like that. The 'official' software knew where to get that 9th bit's value from.

    I remember a friend who went to the US on holiday to buy an Apple ][. Compuer + holiday cost him less than just buying the computer in the UK. A few years ago I was in a surplus store in California, where there was a big cardboard bin full of Apple ][s, going for $15 each. Sad...

    I also know of one large UK Telco that, back in the early 80s, used an Apple ][ as the main link between a VAX and a telephone switchboard in their call centre. The switchboard console was connected via a serial line at some weird bitrate, and the apple serial card was the only thing they'd found that could be easily programmed to match it. It sat there for years without a problem, with the lid off to keep it cool, converting between 9600bit/s RS232 and the switchboard console.

  77. Dabooka

    Overclocking an Amstrad 1512

    I remember being told how to by a new crystal from Maplin or Tandy, to get another 1mhz or so out if it.

    Although I now know we've lept forward a decade....

  78. Anonymous Coward
    Thumb Up

    Happy Days

    My first computer was the PET2001 which I bought on HP - took ages to clear that debt! I played around with the built-in Basic and eventually progressed to Assembler on the later PETs. I was fascinated by the idea of connecting external equipment to the expansion facility, which was a huge connector along the right hand side of the motherboard. So I played around with fairly simple interfaces to start with - switch inputs, LED outputs, DC motor controls etc. all implemented using mostly assembler coded software.

    At work, we had a contract to provide a control system for an automated robotic inspection system, which used several Stepper motors, position encoders (Grey Code) and miscellaneous switch inputs and control outputs. I was of the opinion that this could be best achieved using a 4032 PET and a purpose built interface, connected to the expansion port, rather than trying to implement the entire system in hardware, which was the original concept. The hardware was based around several 6522 via devices and the software was a hybrid of Basic and Assembler.The system worked very well for a long time and was later adapted to suit several other robotic inspection devices.

    Although I really liked the instruction set for the 6502, I also experimented with the Dragon 32 with its 6809 processor - now that one had a great architecture and a super instruction set !! Several later projects were built using that processor............ Happy Days indeed!

  79. dave

    Dragon 32!!!

    god i still got a working one of those

  80. Anonymous Coward
    Anonymous Coward

    MSX anyone?

    Still a great machine, even though it failed to take off anywhere other than japan. Mind you not a bad thing considering it was MS-Basic based....

    Spectrum, Spectrum plus, C64, electron, bbc, RM 380Z (yes - the school where chucking it out in 88/89 and said i could have it and it even had the graphics adapter. B+W graphics rule). I even had a Superbrain with a 5MB (I think) winchester. Nemesis on the MSX though, what a game. Used to know Mark Butler too from Imagine. He lived up the road from me.

  81. andy gibson


    Do we need a thousand and one comments about "my first computer was a blah blah"? Let's keep any future comments in this series to the reviewed computer in general - especially if you came to the computing scene late in life (and by late I mean 1981 onwards)!

  82. Stuart Halliday


    I knew some idiot would post up the poke code required to give Curators of computer museums a headache!

    My excuse for not remembering the exact reason why it would go up in a puff of smoke is easy. Hey man I was only 14 at the time!

    I always wanted a PET since I was 14, but of course could never afford one.

    When Ferranti finally closed its doors 20 years later, I wandered around an empty factory floor seeing what I could pick up cheap.

    There in a corner was an unwanted broken Pet. I had to own it! This was my very last chance of owning my first technological icon!

    How much did they want for it?

    I pay a fiver and it sat in my living room staring back at me for a further 3 years before I gave it to a loving museum. (I got married).


  83. Alan Potter

    @Andy Gibson

    Apart from the fact that your comment makes no reference to the Commodore Pet 2001, I think most people here are actually enjoying this discussion. Before you ask, did join the "Computer Scene" as you so eruditely put it, before 1981.

    But I have this feeling that you are either (a) someone who's been made redundant recently and is feeling ill-will to any sort of merriment, or (b) the sort of project manager I hate, being a project manager myself.

    I also think you mean "specifically" rather than "in general", but that's just my pedantic side coming out...

    Please go and find a thread which shares your lack of humour

  84. Anonymous Coward
    Anonymous Coward


    There was 4 of us with these. We had a contact within Commodore so upgraded our 8K machines to 64K, needed to upgrade power as well so the cassette had to go external. We developed games for the "PET" using these machines and then compiling them to get into the 8K, if we could'nt do it we had tools to shift some of the code into the input/output memory to fit, which was also a neat way to stop people copying them because as soon as they "saved" program it would overwrite the buffer memory. We also made "sound" boxes out of old metal tobacco tins with components inside and attached to the output serial port. What "geeks" we must have appeared but as all of us where IBM'ers working on "real" computers it was just a social thing.

    The day IBM brought out there PC we were all called to meetings with our managers and given the option of stopping work on our "hobby" or leaving IBM. Unfortunately we all made the wrong decision and stayed with big BLUE.

    One thing I do remember about these were how easy it was to fix them when they went wrong. You could juggle the memory to isolate errors...


  85. Ben W
    Thumb Up

    :( I want one

    first computer I ever had was the relativly new IBM PS1 (pre-HDD think it ran from a Rom chip but I could be mistaken) and I miss that shed loads.

    I also had a Sinclare Spectrum but it wasn't the same :(

  86. Ian Johnston Silver badge

    Second life

    In 1982 I won a Commodore 4000 and disk drive for my school in a competition. It was the first disk drive the school had ever owned - my maths teacher kissed me when she found out ...

    Years later - about 1990 - it was surplus to requirements, and they offered it to me. These things had an IEEE488 parallel interface as standard, so they were brilliant for instrumentation, so "my" PET took on a new role doing superconductor characterisation tests in Oxford. I understand that it only retired from that about 2000.

    My greatest feat was to write a VT52 (subset) terminal emulator for it, in basic. The only connection I had was done by going IEEE488 -> RS432 (current loop) with one convertor, then RS432 -> RS232 with another, then through a Gandalf box into the university network. 50 baud was pushing it.

  87. Nev
    Thumb Up

    Good Book

    "On The Edge" by B. Bagnall

    Really good history of Commodore's Computer years.

    Great insight into everything from 6502 design to the

    last Amigas.

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