World's oldest digital computer successfully reboots

Harwell Dekatron

[BeeDeeDubbleU]

After three years of restoration by the National Museum of Computing (TNMOC) and staff at Bletchley Park, the world's oldest functioning digital computer has been successfully rebooted at a ceremony attended by two of its original developers.

[theregister.co.uk...]

[engine]

That's terrific news it was restored. It's a great example of leading edge technology of the time.
I can imagine it being quite noisy, with all those relays clattering away.

I'm not sure today's youngsters would be impressed.

[g1smd]

Their first question is likely to be "how many games are on it?".

The veterans reply should be "we used this thing in a real war, no game sunshine".

[BeeDeeDubbleU]

Much more impressive than a tablet. :)

[londrum]

it probably still boots up quicker than windows

[scooterdude]

I watched a program on the Colossus machine and its amazing how those chaps designed the registers, buses, and other cpu architecture from scratch , foundations cpu tech today

[Rugles]

it probably still boots up quicker than windows

Zing!

[lawman]

I'm guessing valves are what we call tubes.

[SevenCubed]

I was just going to ask if it is chock full of vacuum tubes, don't know if that's what lawman is referring to or not.

[scooterdude]

I think so, they are like really small florescent light bulbs , back in the day, TVs still had them till the 80s, depending on where you were

[lawman]

This is the valve reference:

"The restoration was quite a challenge requiring work with components like valves, relays, and paper tape readers that are rarely seen these days and are certainly not found in modern computers," [emphasis supplied]

I was just going to ask if it is chock full of vacuum tubes, don't know if that's what lawman is referring to or not

Yes.

[added]OK, looked it up. In US they are called vacuum tubes and in the UK they are called valves.[/added]

[incrediBILL]

I've actually worked with these old tech devices and I find it amazing that people managed to build functional computers with hot glowing tubes (valves) stuffed with lots of wires.

I knew a lady that worked on one of those kinds of computers and she said she spent all day repairing those circuits. What's even harder to fathom is that it was this technology that was used to create the space program.

<shudders>

they are like really small florescent light bulbs

Not really since they're VACUUM TUBES and fluorescent tubes are filled with gas which makes them fluoresce. One is for lighting and the other is for electronic circuitry. Huge difference.

Interesting tidbit that a TV picture tube (CRT) was actually used as an experimental RAM device when they discovered that the video scan could not only set the state of the phosphor on the screen but return it's current status.

[g1smd]

The US military laughed when a captured Russian military plane was examined in the 1980s. It was stuffed full of valve-based circuitry - not a transistor in sight. Only later did they realise that all the US planes would fall out of the sky when the electro-magnetic pulse from a nuclear blast fried all their circuits, while the Russian plane using valves would not be affected.

[incrediBILL]

while the Russian plane using valves would not be affected.

Not necessarily true as those thin filament wires easily fracture, just like in an incandescent bulb, when a sudden surge occurs. It's more likely to survive but it's not necessarily going to survive.

[scooterdude]

Some good people spent 1 year trying to ram valve an transistor design into the heads of certain undergrads,,,,, and most of us left sincerely relieved not to be Electronics majors

[incrediBILL]

Since we're on the topic of ancient electronics, anyone else ever have a crystal radio? I don't know if I still have it, but I did have one and they use NO batteries whatsoever. With the mere radio energy in the air you can tune a channel and power an ear bud to listen to the radio.

While crystal radios aren't computers some of my earlier computers running in the 1Mhz range had circuits you could toggle at just the right speed and generate RF noise that would play music over an AM radio or a crystal radio :)

FYI, that RF noise over an AM radio was the "sound" for many of my early video games until someone finally wised up and made a small jack port for the computer which was the start of MP3 players.

[Automan Empire]

"Valve" is indeed another name for "vacuum tube." Most tubes are analagous to a transistor; amplifying a weak signal but using a hot cathode.

The dekatron is a different animal, a decade counter. It is filled with neon, argon, or hydrogen, and uses cold cathodes. Inputting clock pulses causes the glow, thence output, to jump to the next cathode. They can count up or down. There's an interesting wiki article on them, and you can buy dekatron "spinners" on auction sites. Also, check out nixie tubes if vintage tech rings your chimes.

My grandfather worked on vacuum tube computers in the '50s. He told me that tubes numbered in the hundreds or more, and you were lucky to get 15 minutes of use before a tube failed, though the fault tracing systems and methods were surprisingly good.

[incrediBILL]

the fault tracing systems and methods were surprisingly good.

follow the smoke?

[SevenCubed]

Ok guys it's your faults that I'm not getting any work done tonight. All this talk about ancient electronics sent me on a trip down memory lane and I wandered around searching for images of past memories.

First of all I didn't even know about crystal radios. I had to go look that up. I'm surprised it escaped me but I may have used one at some point without knowing what it was. It's possible because at the time my father worked as a Signals and Communications technician for a large mining company and often brought home scrap electronics that my brother and I would try to revive. I quickly realize that it wasn't my cup of tea but I did enjoy use of the technology (my younger brother actually went on to open his own electronics repair shop that he still runs today).

The extent of my knowledge of crystal technology is limited to the RF crystals in my old Johnson Messenger 300 Classic CB Radio. As for vacuum tubes (valves) -- that's what my Geloso G4 Wumpus HAM receiver ran on. I remember it so well and can still feel it today -- the electricity that is -- it had a grounding problem. I never was able to figure out the cause but I eventually got used to the shocks :)

follow the smoke?

See above re: shocks

[lucy24]

Only later did they realise that all the US planes would fall out of the sky when the electro-magnetic pulse from a nuclear blast fried all their circuits, while the Russian plane using valves would not be affected.

Reminds me of when NASA spent wild amounts of time and money developing pens that would write in zero gravity. (I remember the pens, in fact, when they went commercial. You could write notes upside-down.) The Soviets meanwhile sent their guys up with pencils.

those thin filament wires easily fracture, just like in an incandescent bulb

When he was young, one of my father's skills was to jiggle burned-out lightbulbs so the broken filaments came back into contact and they could squeeze some more life out of the bulb. He grew up to work with computers. The lab had drawer upon drawer of what kids all called IBM cards. The ones you clipped to your bike wheel to make lots of gratifying noise. But totally useless for anything else.

Computers were for grownups, though. In school we learned how to use slide rules. Have a nasty feeling this is not a skill that would come back in an instant. I used to know how to use an adding machine too. My brain knows how to touch type-- what is now called "keyboarding"-- but my fingers have ideas of their own.

And no man would be caught dead doing his own keyb-- er, typing.

What forum is this again?

---

Observers at the scene report that the oldest living programmers had to be forcibly dissuaded from breaking a bottle of champagne against the leading edge of the computer.

[BeeDeeDubbleU]

The reason why they were called valves is that a valve is a means of controlling flow and electronic valves controlled the flow of current - just like transistors do.

[lawman]

The Soviets meanwhile sent their guys up with pencils

Come on Lucy; you should know better than to perpetuate that myth:

[snopes.com...]

[lucy24]

Heh. I had the feeling that would turn out to be a canard* but I put it up there anyway. I'm going to assume, before even reading snopes, that they have some pointed haha observations about what would happen with all those pencil shavings floating around in zero gravity.


* "A story so far-fetched you canardly believe it."

[lawman]

what would happen with all those pencil shavings floating around in zero gravity.

Mechanical pencils don't have shavings but there's always a problem with broken lead floating around.

[Old_Honky]

They could have just used crayons.