FACOM 128B – Japanese 1958/59 Relay Computer (Video)

Marc Verdiell is visiting Japan and enjoys a demonstration of the 5000+ relays behemoth, which was Fujitsu’s first computer. The machine is purely mathematical, acting on 69-bit biquinary floating point numbers (8-digit mantissa and 2-digit exponent) based on telephone switching technology of the time. (Instructions consist of three 3-digit addresses and an 8-digit opcode and come from a wide paper tape. The machine also features programmable ROM for lookup tables and subroutines, implemented by perforated paper cards.)
What a machine – and still in full working order!

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(see also a previous post:


)

(Maybe also of interest, over on anycpu joanlluch has just begin thinking of making a RISC from relays, and has begun by surveying the present state of relay (retro) computers:
G6A-RISC
)

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I watched this one last night. Amazing. Nice reproduction PSU as well.

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