El Reg visits two shrines to computing history as the UK lifts coronavirus lockdown The National Museum of Computing and Centre for Computing History have finally reopened with the relaxing of coronavirus restrictions so The Register paid both a visit to see what had and had not changed. The National Museum of Computing The National Museum of Computing (TNMOC) is located in Block H on the Bletchley Park …
A few years ago when we were doing a PC refresh, we had a well-passed official retirement-age PA who was adamant she didn’t want her PC upgraded as it would only confuse her, probably wouldn’t work properly and she had important stuff to get on with etc. etc. So we left her old screen and keyboard in place and replaced “the box bit” under the desk. She was as pleased as anything that we hadn’t upgraded her … and a few weeks later once she was convinced everything was working fine for her colleagues told us she was ready for her new PC! So she got her new screen and keyboard (and yes, I believe we did transfer the post-it notes that may or may not have had her password on … sometimes you need to make life easy on yourself!)
I staggered up to the attic with mine several hundred years ago and I think it's still there. There are more cracks in the ceiling to prove it. The amount of mechanical and electronic technology that we went through to print on paper... I had it connected to my NASCOM, which is probably also up there. Some day, the demolition men are going to have great fun.
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 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.
Just commenting, not complaining. I rather suspect that most casual observers wouldn't even register the generations between the 'scope and the Elliott. My own 1401 often has a similar unit sitting on top of the console, as does a lot of the gear down at the CHM in San Jose ...but for some reason it's still somewhat jarring every time I see it in a photo.
I figured that board was some kind of latter-day breakout box, and wondered (with those DIPs it Shirley has no place in an 803!). The only reason I didn't ask about it is because I didn't think anyone here would have a real answer. Ta. :-)
I hope to visit next time I'm in Blighty.
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 !
Have TNMOC finally made peace with Bletchley (Theme...) Park? Must admit I was pretty disgusted on my last visit a few years back by what seemed like an antagonistic and depressingly dumbed-down approach by Bletchley Park Trust towards anything which didn't fit their simplistic, bring-in-the-crowds approach, with the infamous fence only part of it. Kicking out David White and his wonderful DWS treasure trove was the low point for me. I wouldn't be surprised to hear that a Bombe Water Flume ride was BPT's next big idea!
I see a picture of a Amiga A1200. I had the A600, did get the A1200 after a while and rember fitting a 3.5 inch hdd into a computer that was desigiened for a 2.5. I towered that shit up with a eyetech inteface and gave it a ide cd rom. I used a soilding iron to lift the legs off the suface mounted chips to conected th clock and data lines fo a extearnal keyboard. Mess with my spellin of punction if you wish.
My next-door neighbour worked on Bombe no.6 - and that's all she would tell me. She felt herself still bound by the Official Secrets Act some sixty-odd years after the end of the war and long after the expiry of the secrecy surrounding Bletchley Park. She died around ten years ago and I have to say it - taking all that history with her. No names - if she wouldn't tell me a bout the Bombe, I feel it's incumbent on me not to say who she was, but I have seen her name on a list of the Wrens who worked there.
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