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These are all SWP (South-Western Products, not to be confused with SWTPC) RAMDISK / 8088 MS-DOS adapter boards. Designed for various CP/M machines of the day, these commonly found their way into Kaypro machines, with Zorba machines being a distant second of sorts.

These are designed to sit on top of the drive stack, plug into the CPU port (the Z80 was pulled and placed on an adapter board) and some special software twiddling gave you a 256k - 1MB RAMDISK (depending on the model) or a MS-DOS mostly-compatible machine that used the host as a terminal.

These were purchased in 2013 and had some of the "missing link" software with them which has now been entered into various archives. The boards themselves are of unknown status, but are being kept around as spares for my working unit. The boards themselves date to the 1984/5 time period.

These are all SWP (South-Western Products, not to be confused with SWTPC) RAMDISK / 8088 MS-DOS adapter boards. Designed for various CP/M machines of the day, these commonly found their way into Kaypro machines, with Zorba machines being a distant second of sorts. These are designed to sit on top of the drive stack, plug into the CPU port (the Z80 was pulled and placed on an adapter board) and some special software twiddling gave you a 256k - 1MB RAMDISK (depending on the model) or a MS-DOS mostly-compatible machine that used the host as a terminal. These were purchased in 2013 and had some of the "missing link" software with them which has now been entered into various archives. The boards themselves are of unknown status, but are being kept around as spares for my working unit. The boards themselves date to the 1984/5 time period.

(post is archived)

[–] [deleted] • 1 pt

Glued together with mostly 74 series TTL... forget that CMOS rubbish. Except for those 374 flip flops and the stuff I can't read, we'll pretend we didn't see those.

I can't read the chip the xtal is connected to, but it's probably dividing that 16 mhz by 4.

Curious as to what the blue 8081 is. It sits between two tri-state buffers... maybe it's a PAL or GAL just switching signal paths or some shit like that.

Good on you for archiving that stuff. Looks like that might be a EPROM above the 8088. If it is, probably a good idea to archive the contents of that too.

[–] • 1 pt

The clock chip should be an 8284A.

The blue "chip" is a Bourns 16-2-103 10K isolated resistor pack, the one says "8140" or 40th week, 1981.

[–] [deleted] • 1 pt

Man, I've seen a million SIP resistors but never a DIP... sweeeeet.

[–] • 1 pt

They were common on 70s and 80s stuff, with 90s stuff being SOIC versions. You've probably seen them on newer boards, just didn't recognize it because they look like any other device now.

Bourns and Dale used harvest gold cases Bourns used blue cases Beckman used white ceramic and black plastic GenericCo used any color, I've seen red, blue, black, white, etc.

Not an exhaustive guide, but you can usually assume the manufacturer from the color. Not always, but usually.