"SCSI subsystem" is just a generic term, much like "video subsystem",
"bus interface unit", etc. Everything you have listed is a "SCSI
subsystem". See here:
https://ardent-tool.com/docs/pdf/GG24-4002-0_IBM_PS_2_and_PS_ValuePoint_Subsystems_Dec92.pdf#page=40
(page 40 phys.)
I think IBM used the"SCSI SUBSYSTEM" term instead of something like "IBM
PS/2 MICROCHANNEL SCSI ADAPTER" or "IBM PS/2 Microchannel SCSI Adapter
with Cache" because these local bus implementations simply didn't have a
more descriptive name. They always reside on a planar and were never
shipped as an option/adapter.
But yes, they unique since they are single chip solutions (ignoring the
MCU) and are attached to a local bus instead of MCA.
Nice job noticing the codenames, gonna add "Jalpa" & "Monarch" to the
relevant pages...
On 18.04.2023 16:36, Louis Ohland wrote:
http://ps-2.kev009.com/ohland/Spock_Bermuda/8556_SCSI.html
After probulating, there are TWO PS/2s with a "SCSI Subsystem" connected
to the local bus, the 8556 and the 9556. They use the 16-bit 8032. My
SWAG is that these implementations are pretty close, but if so, why did
IBM make different versions? Further instigation needed.
IMHO, these Model 56 SCSI Subsystems are a unique implementation.
SCSI /A [Tribble]
SCSI Subsystem [Jalpa/Monarch]
SCSI w/Cache [Spock]
SCSI-2 [Patriot]
SCSI-2 F/W [Corvette / Turbo]
All other system board implementations are connected to the MCA bus.
Gearbox, Bermuda, 9585-X, 9585-K.
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