When thinking of retrocomputing, many of us will imagine machines such as the Commodore 64 or Apple II. These computers were very popular and have plenty of parts and documentation available. Fewer will go back to the Intel 8008 or even 4004 era which were the first integrated circuit chips commercially available. But before even those transistor-based computers is a retrocomputing era rarely touched on: the era of programmable vacuum tube machines. [Mike] has gone back to the 1950s with this computer which uses vacuum tubes instead of transistors.
The computer has an eight-bit architecture and features most of the components of any modern transistor-based computer of similar computational ability. Memory, I/O, an arithmetic logic unit including a carry bit that allows it to do 16-bit arithmetic, are all implemented using 6N3P dual triode tubes that date to the 50s and 60s and would have been used in similar computers like the IBM 700. All of this drives a flight simulator program or a Fibonacci number generator, demonstrating its general purpose computing capabilities.
Of course, tubes were generally phased out in favor of transistors largely due to their power and space requirements; [Mike] needs a stepladder to maintain this computer as well as around ten minutes each time he starts it up to allow the tubes to warm up, with each module needing over three amps of current each. It’s a hugely impressive build and we’d recommend checking out the video linked below to get more details on its operation. If you’re looking for something a little more accessible to get into the world of vacuum tubes, this single-board tube computer fits the bill.
I had a mentor in the beginnon of the seventies who had worked with a tube based swedish computer financed by Wennergren.
For a short while it was the world’s fastest, but a few months later it was passed and was let in the dust 😀 in the project was terminated.
One thing that was learned, it was not a good idea to do preventive maintainanse to clean the tube sockets.
For the love of all that’s holy…can people make videos with the proper aspect ratio! this winged look drives me CRAZY.
Mind you, I work for a broadcaster so I’m more sensitive to it than others.
Neat computer otherwise.
This is known as VVS, the vertical video syndrome.
It’s quite a widespread phenomenon that’s caused by long term exposure to smartphones.
https://www.youtube.com/watch?v=f2picMQC-9E
Yeah, that annoys me, too. All of the YouTube “shorts” are shown in that orientation, so I wonder if there’s some incentive to do that related to cell phone viewing or posting on Tik Tok where all videos there I’ve seen re-posted on YouTube or X are in that aspect ratio. OR are people just too stupid to rotate their phones 90 degress?
For shorts (and tiktok and reels etc.) the idea is to make it as frictionless as possible for people to continue watching videos. Same logic behind short duration videos. If the user doesn’t have to rotate their phone, they are a little bit more likely to keep watching clips of a few seconds long and then flicking to the next one. Once the subject has been suitably hypnotized in this fashion, ads can be inserted between the videos.
Great project ! I had problems with the video too but otherwise very informative. This brought to mind a favorite Star Trek quote…”I am endeavoring, ma’am, to construct a mnemonic memory circuit using stone knives and bearskins” – Spock – City On The Edge of Forever- STOS.
I’m absolutely thrilled to see hundreds of hard-to-find NOS vacuum tubes being aquired in big quantities and being used just to produce one popular youtube video.
Computer tubes (unlike the ones this one is using) were special in a sense that they could operate in cutoff for a prolonged time; regular tubes (like the ones used in this computer) are damaged when used for a prolonged time in cutoff, so these tubes will end up in the trash shortly.
I’d agree if the “6NP3” tubes he’s using were actually hard to find or particularly desirable, but are they really, even now?
I mean, they’re definitely not intended for the purpose, and I’m sure they’ll burn out faster than computer tubes designed to slow down cathode poisoning, but we’re talking about a cheap soviet knockoff of the 2C51 that was manufactured in Russia up through the 1990s, with clones still being manufactured in China to this day. Do you really think these are going to collectors and not the landfill if they’re not used for something like this?
No need to agree – just imagine someone making an entertainment show about flattening two dozens of ’63 Corvettes with a roller, assuming that those are just cheap American knockoffs of the SL300, “in the name of science”, and making $10M from the show, which would recover the cost of cars.
For me, this project (and all others like this) is a mass destruction of original vintage electronic parts -even though he has put lots of effort and money into it- for no real purpose. Making popular “Crazy” clickbait youtube videos to recover the cost of vintage parts isn’t what hacking is supposed to be about IMO.
Is this project showing or teaching anything new to the public? If he wanted to show anything new about CPU or computer architecture and desparately wanted to use tubes then why didn’t he use the still made Chinese tubes (assuming it’s true)?
Over a dozen vintage Plymouth Furies were destroyed making the movie Christine, and pretty much every time the General Lee took a jump in the Dukes of Hazzard it destroyed a genuine 1969 Dodge Charger — hundreds of them over the run of the show.
Fortunately, every jumping General shot in DofH was used on at least half a dozen episodes.
its no clickbait. did you read the story? no, you did not. i did not watch the video though as i dont like vertical aspect ratios.
“…are damaged when used for a prolonged time in cutoff…”
Please explain.
vacuum tubes and their ilk (including nixie tubes, CRTs, and many fluorescent lights) are subject to something called “cathode poisoning”, where the cathode undergoes a chemical process that reduces its emissivity (which is a problem since the cathode’s whole job is to emit electrons).
As [Geza] says, a particularly serious (and irreversible) form of cathode poisoning can happen when tubes are left in the cutoff state (more specifically, when the cathode remains heated but no current is flowing). This poisoning causes a resistive layer to slowly build up on the cathode over time until the tube eventually becomes unusable.
(Incidentally, it’s rarely the biggest culprit, but this is one of several reasons that CRT monitors and fluorescent tubes become dimmer as they age).
Anyway – when using a tube for amplification, you’re almost never in cutoff, because analog inputs don’t really drop to zero- they just reach a point where there’s nothing worth amplifying.
When using a tube as a binary logic gate, on the other hand, the cathode deals with cutoff quite a lot, because that’s what a binary “zero” is.
This was a big problem for the reliability of early vacuum tube computers, and a lot of effort went in to engineering cathodes that could survive being in cutoff for much longer, and indeed to specific “computer tube” designs that were much more durable in that application.
“(Incidentally, it’s rarely the biggest culprit, but this is one of several reasons that CRT monitors and fluorescent tubes become dimmer as they age”
Yep, us old TV repairmen were quite familiar with a CRT Restorer, a device that heated up the CRT cathodes to “boil off” a bit of the “crust” and hopefully get a little more life out of the CRT. I was able to by an advanced type called the REM for about $25 (used). Little did I know that CRTs would soon be obsolete and that it would only be used a couple of times. Unlike a vacuum tube tester which is still seeing use.
The process is known as “rejuvenating”, I think.
https://www.youtube.com/watch?v=YikOY8WTnLU
Yes!
That term didn’t come up to the surface while I was writing the comment.
Thanks!
I believe there were a number of 12AX7-ish “computer-grade” variants developed in the early 50s specifically to operate in this mode. I do not know what techniques were employed to make them resistant to cathode poisoning. Does anyone know the details?
“…are damaged when used for a prolonged time in cutoff…”
Please explain.
Again?
B^)
It’s because when you submit a comment you just get a blank square where your comment should be, so you don’t get feedback that your comment has actually been accepted, therefore you try again (until you figure it out for yourself). It’s a new bug, started a couple of months ago.
Also, “save my name in this browser” is broken too.
This is my observation. When I post, I save the text to the clipboard (in case it goes wrong) then hit the Reply button and just leave it. I bring up the page in another tab and wait + refresh for it to appear.
I suppose it’s ironic that I find it annoying to be required to use hacks to make this site work.
Well, what a delight to have it in your room and let it run endlesly so you forget the blizzard outside. Yet in the summer is not so much fun. And so with the electicity bill.