Retired Man Turns Spare Room Into Soviet-Era Supercomputer
Arthur T Knackerbracket writes:
You can go retro by using an old video game console or a PC from the 1980s, but why stop there when, like one man, you can build your own vacuum tube computer using 75-year-old recycled components?
A UK resident who identifies himself only as "Mike" has done just that, as detailed on his tube computer website and accompanying Hackaday project page. Mike's tube computer is primarily made up of 460 recycled, Soviet-era 6N3P vacuum tubes, which were common enough in their age to be readily and cheaply available online.
"Many were used and then stored for over 50 years, so life expectancy may be questionable," Mike explained on Hackaday. A new 6N3P tube is supposed to have around 500 hours of life, but because each has been used, its current condition is essentially a mystery. Throw in manufacturing inconsistencies of mid-century Soviet Russia, and each tube had enough variability to necessitate extensive testing, Mike explains in the technical writeup on his website.
"I calculated the component values and tested the results, but in many cases the theory did not accurately match the practice," Mike writes. "So I built a test rig to test the viability of various component values and found a range of values that seemed to work in most cases."
All told, Mike's tube computer, with its 460 6N3P tubes, consists of 920 thermionic triodes that use heat to release electrons for his computing work. Those tubes are mounted to 46 separate 10-tube PCBs, which in turn sit on five backplane PCBs. The entire thing includes a control console that Mike describes as "far too simple" and in need of a complete redesign to better handle variations in the computer's logic levels.
It takes between 10 and 15 minutes for the entire system to stabilize once switched on, Mike said, resulting in a "warm and cozy computer room." The tubes all power up in random states, requiring the machine to be reset each time it is switched on, but then it's ready for the fun part: computing.
The entire thing uses NOR (i.e., not OR) gates, just like the Apollo guidance computers that got humans to the Moon, which allows it to be a bit smaller than some of the other classic tube computers of yesteryear. As for what it can do, well - 16-bit math is a possibility, as well as anything else that can be done with a limited set of 16 instructions on a 4-bit instruction register.
Mike has it configured to output a 64-bit Fibonacci sequence and, more excitingly for his grandchildren and the kid in all of us, plans to use it to power a simple flight simulator once its I/O system is finished.
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