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Comment by uberalex | Hacker News Reader

I apologise if I've failed a reading comprehension check, but did the article say what the computer was used for?

"The FACOM128B greatly contributed to technological advancements during the period of Japan’s high economic growth from the early 1960s to the early 1970s. The computer was used in the design of camera lenses and the YS-11 plane, Japan’s first passenger aircraft developed after the end of World War II."

I suspect that parent wonders what it does now. Which is likely ~nothing. But I am curious how it compares with current machines. Comparable to an i5 desktop? Or to a smartphone?

With 13K of memory[1] I doubt you could compare it to anything modern bigger than the simplest e-toy...

1: http://museum.ipsj.or.jp/en/heritage/facom128b.html

True, but some of those old machines could do amazing stuff with ~huge datasets. Basically by just doing one ~simple operation per data pass. Read, do something simple, write. Then repeat that as many times as needed, with a different operation. Sort of like executing a program one line at a time.

They did crazy tricks because timesharing wasn't invented and whatever program was running had the full machine to itself. Also, designers of these computers usually built everything around the flow of data so that a CPU would have as little as possible to do to read tapes or cards.

Right. And there wasn't much "full machine" to have.

Probably roughly equivalent to the chip equipping your microwave, if it's not too recent. Except that your microwave chip is most probably faster and more reliable.

Here's a comparison between a RPi Zero and a 1957 Elliott 405 (from the UK): https://www.spinellis.gr/blog/20151129/

On a simple clock comparison, it was about a million times slower than a Raspberry Pi Zero. Computing has come a LONG way

It's about an Arduino with a 10x slower clock.

An Arduino Uno runs at 16MHz, and averages about 1.5 instructions per clock (estimated by multiplying the best case 1 instruction per clock by 1.5), so about 11M instructions per second.

The FACOM128B is asynchronous, and takes about 0.15s per instruction using the same estimation (1.5x best case), so about 7 instructions per second. See timings at: http://museum.ipsj.or.jp/en/computer/dawn/0012.html

However, the FACOM128B is 69bit, and the Atmega is only 8bit (it can do some 16bit operations, but those are limited to certain registers and operations, so I'll just assume it's only 8bit). 69 is about 9 times bigger than 8, so I'll assume the FACOM128B can do about 9 times as much work per operation (there is overhead in calculating wider results from narrow operations, but the full width isn't always needed, so this simple estimate seems reasonable to me).

Therefore the FACOM128B is like an Arduino with about a 190000x slower clock.

Nice estimate. And not surprising, given that it uses relays. Not even vacuum tubes.

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