The Electronic Computers, Part 2: Colossus
technicshistory.wordpress.com
technicshistory.wordpress.com
Colossus wasn't a computer as we think of one today. It was a key-tester, like a Bitcoin ASIC. No memory, just a few registers. No stored program.
What we think of as a computer today is a general purpose, stored program, digital machine. Colossus was a special-purpose, hard-wired program digital machine. There were many such special-purpose machines before full-fledged computers appeared.
Just before WWII, several groups were working on electronic arithmetic units. A. Halsey Dickinson at IBM was working on vacuum tube arithmetic, and by 1942, had an electronic multiplier.[1] Some of those circuits were used in the ENIAC, and by 1946, IBM had an electronic multiplier as a product, the IBM 603.
IBM's 600 series machines somehow don't seem to be mentioned much in the history of computing. They were commercial products, so they had to work reliably and be cost-effective. The IBM 601 (1936) was the first fully automatic multiplier - electomechanical, punch cards in and out, a few registers of memory. The 602 and 602A added division. The 603 did the same job as the 602, but using vacuum tubes. The 604 (1948) was plugboard programmable with up to 40 program steps. There were more 600 series machines, up to the IBM 650, on which Knuth learned to program. The 650 had a magnetic drum and real stored programs.
The big problem in the early days was memory. It was clear by the mid-1930s that electronic arithmetic was possible, but nobody had a good storage device yet. The early approaches were recirculating delay lines (slow, sequential access, not much capacity), magnetic drums (slower, sequential access, more capacity), and Williams tubes (faster, expensive, not much capacity, but random access). Core memory was the first technology that really worked well. IBM developed automatic looms for weaving it, which made it sort of affordable. Still, through the 1960s, memory was about a million dollars a megabyte.
There was a whole sideline of special-purpose electronic computing devices in the 1950s and 1960s, when general-purpose computers were too expensive. Teleregister did special-purposes machines for stock markets and airline reservations. American Totalizator did special purpose machines for racetracks, and was an investor in Univac. There were cute little machines such as the Mathatron (an early calculator the size of a desk) and Mem-O-Ree (an inventory control system). These all had electronic computing components but were not full general purpose computers.
[1] http://www-03.ibm.com/ibm/history/ibm100/us/en/icons/ibm603/...
The history of that site is remarkable and accessible, and on the same site is The National Museum of Computing, which has pretty much one of everything since the dawn of computing.
Anyhow, one of the people I was there to work with brought me over to Bletchley Park and to the museum. It was easy to spend the full day there between the two.
So, even if you don't live there, I recommend visiting even if you're more than an hour away. I seem to recall the drive taking about an hour and a half, though my memory may be fuzzy. I was there in 2007 and I think they'd just recently opened.
If I'm back in the area, I'll be sure to visit again.
Either way, it's well worth visiting. Given that it had just opened, and now been more than a decade, I suspect they have all sorts of additional displays these days. So, when I'm next in the general area, I will make it a point to visit again.
Tangentially related: I also highly recommend the Natural History Museum. I really enjoyed that. Though, I'd recommend setting aside a couple of days for that one.
Especially relevant for this audience is its Information Age gallery which covers "6 networks that changed the world", telegraph, broadcast radio and tv, telephony, satellite (including GPS), the web, and cell phone networks.
Best of all both museums are free to get in (donations welcome).
I also enjoyed the Brittish Museum, London Museum of Steam and Water (I think that was the name), the Museum of London, and Clink Prison Museum, though that was kind of small.
I also did a police museum but I can't remember the name of it.
London has some great museums and a fairly long history, so I highly recommend anybody visiting make it a point to visit at least a few of them. They were also inexpensive to visit, as I recall. I think some of them only required a donation? I am not entirely sure, it has been quite a while since I have been back. I've only had one post-retirement visit.
Hmm... I should go back. Maybe I'll go over the winter.
I was just talking with the missus and she's never been to the UK so we are tentatively looking to go over the coming winter, probably after the new year.
I will put that one on my list of 'must do stuff.' I've seen the museum pop up in documentaries and have just taken a peek online. It looks like it will be a good time.
Seriously, thanks. I love the UK and museums. Being reminded of another one is a good thing. I'd forgotten all about that one.
It's too bad that I can't time it to do one of the Royal Institution Christmas Lectures. I have wanted to do one of those, in person, for a very long time. Fortunately, I'll be able to watch them.
(warning, spoiler)
If you liked the movie 'Trancendance' from a few years ago, check this out... you'll see some awesome parallel storytelling.
I find that utterly incredible. What a feat of engineering for the 1940s.