* Posts by PeterO

52 publicly visible posts • joined 4 Sep 2009


Eben Upton on Sinclair, Acorn, and the Raspberry Pi


Not quite what I said....

At TNMOC we use a Pi to run an emulation of the 2966 when the real machine is not in operation, but the real 2966 uses an SD card for it's mass storage as we don't run any of the real disk drives for environmental reasons.

Ready for the Linux 6.0 splashdown? Here are some of the highlights


Early version numbers......

Who remembers 0.99.X ?

Farewell to two pivotal figures: The founder of Inmos, and the co-creator of MIME


Re: Not quite true.....

I think it's a case of a "off the cuff" comment at some point in the past being exaggerated or misinterpreted and then taking on a life of it's own.


Not quite true.....

I know you shouldn't speak ill of the dead, but according to the former Elliott employees I've spoken to, Iann Barron did not design the Elliott 803. He may have had a minor role, but that's all.

In Simon Lavington's book "Moving Targets Elliott-Automation and the Dawn of the Computer Age in Britain, 1947 – 67" page 352 it says

"Iann Barron was involved as a Vac student but played no part in the real design [of the 803]"

The design team was John Bunt, Jim Barrow, Laurie Bental, Roger Cook.

I have Laurie Bental's original hand drawn logic diagrams from when he redesigned the 803A into the 803B!

Peter Onion

Elliott 803 Curator

The National Museum of Computing.

Not to dis your diskette, but there are some unexpected sector holes


Re: You were lucky

One of the popular design of high speed paper tape readers was based on a design from Cambridge University. I think it was originally an EDSAC II peripheral. It uses a continuously rotating capstan above the tape, a free clutch roller under the tape, and a brake pad to stop the tape on a single character even when going at full speed. The clutch and brake are both operated by solenoids. The maximum speeds were 250/500/1000 cps. The 250 cps versions didn't have a brake and relied on tape friction to stop the tape.

Anyway, the design was licensed to Elliotts, and it appeared on their own 800s/900s/500s/4100s and also later ICL 1900 machines. We have examples at TNMOC fitted to Elliott 803 and 903, and also the Marconi TAC.

Here is the 500 cps version on our Elliott 803.


An example of a variation on the same theme is the Trend UDR 350.



Unable to write 'Amusing Weekly Column'. Abort, Retry, Fail?


Elliott Algol Error 49

The Elliott 803 Algol Compiler only produced numeric error codes which had to be looked up on the manual.

My favorite one is "Error 49 : Program too large to complex to be compiled at all".

These days there would be an emoji at the end rather than the added "at all" for extra emphasis!

El Reg visits two shrines to computing history as the UK lifts coronavirus lockdown


Re: That 'scope ...

If you do ever get over here please get in touch as I'm not at the museum every day so we would need to coordinate if you want to see the 803 in all its glory !

I have in fact just upgraded the LED display to us a Pi PICO rather than a PIC thus putting another generation between it and the 803 !


Re: That 'scope ...

You are welcome to visit to come and see why I use a modern DSO to diagnose faults ! I'm not sure I could have kept the machine working this long if I had to use an analogue (non-storage) 'scope. I can see no point in making the job harder than it has to be !

Did you notice the board behind the 'scope that has two rows of 48 LEDs ? It captures and displays one word time's worth of bits from two signals. It is mostly used to capture, hold and display the last value read from the core stores when a parity error occurs. The store test programs write a pattern of all ones or all zeros into memory locations, so the board makes identifying the faulty bit much easier.

I have great deal of admiration for the field service engineers who fixed these machines for real in the 1960s. Luckily I was able to learn from one of them when we did the original restoration work nearly 30 years ago.


Re: you'll have to find out for yourself.

They are signals within the core store read amplifiers. To be honest I'm really not sure how they manage to detect the difference between a "1" and a "0". But they do, and they get it right nearly all of the time.

The 803 is a serial machine, so it's all about "pulse" or "no pulse" for ones and zeros, not "high" or "low" voltages.


you'll have to find out for yourself.

Well it turned out to be loose connector on the side of the core store box, possibly disturbed during the earlier repair of the DC-DC power convertor that is located next to the store box!

Completed Netflix? Indulge your inner nerd with a virtual talk from a computer museum


Re: Why scheduled times?

You are not just watching a pre-recorded video. Every tour is different. We have multiple tour guides and each has their own style. Also we can tailor tours in terms of duration and content to meet specific groups requirements. And how would you ask questions of the guide on a pre-recorded tour ?


Fame at last :-)

"a talk on vintage computer emulation by ALGOL 60 and Elliott 803 botherer Peter Onion." March 6th if you are interested :-)

Bletchley Park Trust can’t crack COVID-caused revenue slump without losing staff


Re: I'm sure they are trying

Please don't mix up "The computing museum part " (properly called The National Museum of Computing" or TNMOC for short) with the Bletchley Park Trust (BPT) . They are two separate organisations, with TNMOC paying rent for their buildings to BPT. TNMOC is facing the same lack of income from visitors as BPT but it makes more use of volunteers for it's operations. The volunteers have been working hard during the closure to make it as safe as possible for reopening (and to do lots of redecoration).

TNMOC has been regularly putting "#AskTheExperts" interviews on it's YouTube channel while it has been closed, the latest going up only 4 days ago (so not sure where you got 4 months from).

The sun is shining, the birds are singing. You can shut the curtains and tour The National Museum of Computing in VR


Re: no bombe at TNMOC

A couple of years ago in April 2018 the Bombe moved from BP to TNMOC.

If you try the virtual tour you'll see the Bombe in the room immediately to the left of the entrance.

Linus Torvalds pines for header file fix but releases Linux 5.8 anyway


Let the compiler help

https://en.wikipedia.org/wiki/Pragma_once solves it for me :-)

ALGOL 60 at 60: The greatest computer language you've never used and grandaddy of the programming family tree


Re: .. never used .. ?

"The next year the college upgraded to an Elliott 1603, with a massive 16k of RAM,"

Maybe you mean an ICL 1903 , because Elliotts never made a machine called a "1603".


Rugby College course notes

For those who have mentioned learning Algol 60 at Rugby this may be interesting : https://www.peteronion.org.uk/ALGOL/RugbyAlgol.pdf


Re: It started my career move...

The Elliott 500 and 1000 char/sec tape reader design originally came from Cambridge University Mathematical Laboratory's EDSAC team.

See https://www.cl.cam.ac.uk/downloads/books/CambridgeComputing_Ahmed.pdf page 60.


Re: Early Uni Computing

You'll soon be able to relive it all in stunning 3D :-)




Re: It started my career move...

The Algol Plotter Package (Library Tape P104) was a precompiled tape which contained the output of pass one of the compiler (called Own Code) and various bits of compiler state. It was a binary dump of the Own Code so loaded faster than running pass one on the corresponding source code. Your source was then read in and its Own Code appended that already in store. Pass two then read the combined Own Code to produce the executable in core.

That code that could never run? Well, guess what. Now Windows thinks it's Batman


Old Unix kernels never die !

Back in the days of BSD4.3 Unix I was a post-grad student and I built a kernel for a VAX11/750 to try and debug poor NFS performance between the VAX and a IBM PC/AT that had an Enthernet card and ran NFS client software. Several years after I had graduated I got an email from the then sysadmin asking if I knew anything about all the debuging messages with my user name in them that had appeared on the console printer overnight ? And yes it was a proper printing terminal.

Seems my kernel had never been replaced with the original after I fixed the NFS issue in the PC software !

Father of Unix Ken Thompson checkmated: Old eight-char password is finally cracked


Re: Proof of XKCD

5hrs late though !


I had the opportunity to spend a few minutes with Ken Thompson when he visited The National Museum of Computing a few weeks ago :-)


COBOL: Five little letters that if put on a CV would ensure stable income for many a greybeard coder


60 years of Algol 60 coming up next year :-)

Das geeks hit crowdfunding target: IBM mainframes are coming home


Re: Love this bit!

There are multiple responsible "Peter"s at the museum :-)

Sysadmin shut down server, it went ‘Clunk!’ but the app kept running


I'm sure I'm not the only one to have pulled the disk in the failed slot out of the perfectly working raid array :-) "Why are they both beeping at me now ?"

NASA dusts off FORTRAN manual, revives 20-year-old data on Ganymede


Working paper tape readers are not that rare :-)




Microsoft keeps schtum as more battery woes hit Surface sufferers


Re: apparently you don't have to Buy MS to get the Surface feeling

The Dell ad where the guy says something about needing a long battery life when going to places with no electricity seems particularly ironic :-)

'I'm sorry, your lift has had a problem and had to shut down'


Isn't there a "Windows for Warships" ?

Facebook replaces human editors with McChicken romping, Fox News faking AI bots


Who or What ?

The AI isn't even capable of spotting the difference between a "topic" and a "person"...

Joe Wicks

1.5k people talking about this

Not only do I not know what a "Joe Wicks" is, but this tells me nothing about what it has done, so zero chance of me clicking on the link.

'2nd referendum' topples site


“Predictive analytics can help identify where an issue might occur before it takes place,”

Pity that wasn't applied to the whole brexit situation !

This is Sparta? No - it's Microsoft Edge, Son of Internet Explorer


At the edge or in the middle ?

"It refers to the idea of being on the edge of consuming and creating," Being at the edge is only one step away from being an outsider or outcast ?

Surely they should have called it "IM" (In the Middle) ?

'Camera-shy' Raspberry Pi 2 suffers strange 'XENON DEATH FLASH' glitch


That'll be me then....

"A user with the handle PeterO said:"

Raspberry Pi B+: PHWOAR, get a load of those pins


ElReg on the pulse as normal

I can only assume that the ElReg Journos have been on their summer hols for the last 6 weeks since this was released in July

Try to keep up chaps !

Volunteers slam plans to turn Bletchley Park into 'geeky Disneyland'


A well researched summary

Best summary of the situation I've seen : http://freelance.halfacree.co.uk/2014/01/disharmony-at-bletchley-park/

Elderly Bletchley Park volunteer sacked for showing Colossus exhibit to visitors


BBC content was removed due a copyright issue. It's back now with just one "still frame" of a picture removed near the beginning of the piece.


Just to clear up some misunderstandings. You are (and will) will still be able to view Colossus by visiting The National Museum of Computing rather than the Bletchley Park trust's site. Colossus gallery is open every day, the rest of TNMOC is open Thursday,Saturday and Sunday afternoons.

See http://www.tnmoc.org/visit for full details.

Alcatel-Lucent and BT unveil super fat pipe, splurt out 1.4Tb per second across London

Thumb Up

At least there is no mention of this being to do with "superfast broadband" in ElReg's coverage, unlike every other news site that doesn't understand the technology.

Sinclair's FORGOTTEN Australia-only micro revealed!


Even the wikipedia page on the "One per Desk" mentions that it was marketed in the UK by BT as the "TONTO".

Tracking the history of magnetic tape: A game of noughts and crosses


Technology Dead End

In the 1950s and 1960s Elliott Bros. used what was called "Magnetic Film" for the backing store on their 405 and 803 computers.

An 803 with three film handlers is shown here:


Operating handlers are show in the segment between 1:10 and 1:30 in this Pathe news reel:


From Wikipedia:

Optional mass storage is available on an unusual magnetic tape system based on standard 35 mm film stock coated with iron oxide (manufactured by Kodak). At the time this was in use by the film industry to record sound tracks. Elliott's factory at Borehamwood was close to the Elstree film studios which explains the use of the 35mm sprocketed media. The 1000 foot reels held 4096 blocks of 64 words per block (4096 x 64 x 39 = 10,223,616 bits, or the equivalent of about 1.27Mbytes).

Although we have a Film Handler in good condition at The National Museum of Computing we don't have the cabinet full of logic boards (called the "Film Controler") needed to interface the handler to the 803 CPU.

Rise of the machines, south of Milton Keynes


Re: Tunny

See http://www.tnmoc.org/explore/tunny-gallery for details of what is at the museum.


Re: Elliott 803, paper tape and teletype

Hi Chris! Sadly some of the details of the Elliott machines got a bit mixed up by El Reg's Journo ! Probably they were too excited by it all :-) I would trust your memory. There is a picture of the 803 in P4 hanging on the wall behind the 803 at TNMOC. Only yesterday I was running some HCODE programmes on the 803.


@Lars (Elliott)

Rugby College of Engineering and Technology had an Elliott 803 delivered in 1962, so come and revive at least some of your memories. We don't have an authentic operator though !

Brit 2.5-tonne nuke calculator is World's Oldest Working Computer


Re: 1.5kW?

Decatrons are "cold cathode" devices, so they produce very little heat (just like the orange neon indicators in mains switches).


Re: Bletchley Park is awesome.

If all you want to do is visit the "geek-gasam inducing collection of computers", then you don't want to visit the Bletchley Park Trust as such as their tours cover the war time story (intersting as it is) but don't even include a visit to Colossus any more. What you want to do is visit "The National Museum of Computing" which is a separate museum located on the BP site.

DEKATRON reborn: Full details on World's Oldest Digital Computer


Re: Try log tables

The "order code" (and lots of other information) is available on the CCS pages ....




Re: The "The paper tape output " in the picture...

... is actually a modified Creed 7 teleprinter adapted to take 5 bit parallel rather than serial data.

Grumble grumble. People that can't tell their Creeds from their Fridens :-)


Virtual Nazi-code-cracking Colossus in fundraising appeal


If you "pop along" now you won't be able to see Colossus as it is enclosed in a protective box while the building work goes on around it. The rest of TNMOC is open as normal.