Posting some pictures in the coming days from old computer tech I build roughly 35 years ago when 6502 and Z80 were the hotness (and to a lesser degree 8080, 8085 and 6800).

The core of my CPM 2.2 system. Z80 CPU, 64k memory, 4k EEPROM containing boot code and CPM BIOS moved into bank switched additional memory on a different card. Nominally running at 4MHz, however ran with 5MHz. Everything hand wired and soldered.


Again, build about 35 years ago.
192Kb dynamic RAM card. Top-level 1Kb from CPU 64Kb bank is shared between all banks (for bank switching). Most of the CPM BIOS was running in this card. The roughly 160Kb remaining was used as a RAM floppy drive.

· · Musky · 2 · 0 · 2

Continuing my blast from the past. The floppy controller card of my system, which drove 2 5¼ inch drives. Later, when I had switched to an Atari ST520 I connected the floppy drives to the Atari. Some bucks needed to be saved. The chip was the WD2797, the best at the time I think.

Another blast from the past. The keyboard of my CPM system, so heavy you could do serious damage with it. Each key base contains a magnetically operated Reed switch, while the magnets were sitting in the moving part. The Z80 SBC with SIO, PIO and 2k EEPROM running the show. Keyboard matrix completely re-wired to fit existing scheme. The function keys were specially configured to produce Wordstar text processor sequences. Data via serial RS232 line.

@chairraver I'll file these under "strangely satisfying photos"

@chairraver I absolutely LOVE the hex numpad, I've never seen that before!

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