News World's oldest digital computer restored to former glory

[Gareth Halfacree]

Harwell's Dekatron, or WITCH, lives again.
http://www.bit-tech.net/news/hardwar...arwell-witch/1

[mi1ez]

I've never really thought of a digital system being anything other than binary!

[blacko]

....i want to say "but can it...." but i'm holding back as this is a legendary computer, up their with other legendary computers and digital devuces such as the casio watch of the 1980's, the Amiga 1200 and Stephen hawkings.

[Blademrk]

I think it would have a crisis if it tried to run Cry....

Nice to see that not all the old computers were resigned to the scrap heap.

Although the acronym doesn't really sit well in translation with the Harwell prefix: "The Harwell Woverhampton Instrument for Teaching Computation from Harwell" lol

[Shirty]

What a wonderful thing - and close to your heart too Gareth if I'm not mistaken

[Gareth Halfacree]

Originally Posted by Shirty

What a wonderful thing - and close to your heart too Gareth if I'm not mistaken

Very true - in fact, I donated some cash to its restoration a couple of years back. Happy to see it went well - just a shame I couldn't make it down there for the official switch-on this afternoon.

[schmidtbag]

"Even its method of operation is unique in the modern world: unlike today's computer systems, which operate in binary, the Harwell Dekatron operates in base 10 - the same decimal system as adopted by most human societies, in deference to our ten fingers."

It makes me wonder how exactly this operated. The thing about modern digital computers and binary is binary is a complement to digital, where something is either on or off, 0 or 1, yes or no. The only way I can really understand how the Dekatron works is if this computer only has a handful of specific built-in tasks (in other words, can not be programmed to do anything else). I can't really imagine how a programmable computer can be operated in decimal.

[Griffter]

it does not say anything to put it into perspective how fast or rather slow it is in todays standard pc's... like it took it 5min to calculate the e=MC2 or whatever. can someone give a reference?

[Gareth Halfacree]

Originally Posted by Griffter

it does not say anything to put it into perspective how fast or rather slow it is in todays standard pc's... like it took it 5min to calculate the e=MC2 or whatever. can someone give a reference?

It takes about five minutes to do a long multiplication - roughly the same length of time it takes someone to do the same sum by hand on a comptometer. Its design goal was reliability, not speed: although it was no faster than a human, it could keep running for days. There's a story from its early days: one of the scientists challenged the system to a race. Being fast with his figures, he pulled out into an early lead - but had to stop, exhausted, after half an hour. The Dekatron, meanwhile, kept on going. Its longest uninterrupted run was around ten days - and while that might not seem like much when I'm working on a desktop that had been running for three weeks before I took it down for a kernel upgrade, in the days of relays and valves that was something pretty special.

So, you're looking at a machine that takes five minutes to do something a 3GHz desktop could do in a few millionths of a second.