Model 5580

Power Supply
PS/55 Processor Complexes

General Information
Processor Complexes
SCSI Limitation
Server Models Other Than 5580
Some tips for 5580/5560

Content created by Sandy. Edited by Major Tom.

General Information

PS/55 Model 5580 is the Japanese equivalent of PS/2 Model 95 (8595).

Basically there are 2 variants of this model. One is the -Yxx model which uses processor complex similar to the PS/2 Type 1 "K" board. The other is the -Wxx model with complex derived from the PS/2 Type 2 "H"/"L" board. The BIOS P/N is different when compared to the original PS/2 boards.

They were entry server models.

5580 Series Lineup (-Y/W, original HERE)

Model CPU Memory
HDD Video
5580-Y0B/Y0C/Y1C/YEC/YYC 80486DX-33MHz 4/32MB
(8/32MB Y1C,YYC)
160-2GB PS/55 DA
5580-W08/W0B/W0C/WY8/WYB/WYC 80486SX-25MHz 4/32MB
(8/32MB WYx)
80-2GB PS/55 DA
5580-W2B/WAB/W2C/WAC 80486DX2-50MHz 4/32MB
(8/32MB WAx)
160-3.2GB PS/55 DA


Model 5580 uses the 8595 1S1P planar. No distinctive differences.

Processor Complexes

80-Yxx Complex (486DX 33 MHz)
80-W0x/W2x Complex (486SX 25 MHz / 486DX2 50 MHz)
DX2-66 Upgrade Type-A Complex (486DX2 66 MHz)

SCSI Limitation

Models 5580-Y/W use the older long SCSI /A with cache adapter (SPOCK 6451018). Even if the newest SPOCK is used, 5580 can't use hard drives larger than 1GB to IML. In order to unlock full potential of the newest SPOCK, 8595-J Type 3 complex or any Type 4 complex should be used.

Can 5580 Take Regular PS/2 Complexes?

The answer is "Yes". But you have to use the corresponding *PS/2* reference and diag disks to configure the system. Some of my friends managed to configure a Type 3 DX-50 complex and Type 4 "N" and "Y" boards on 5580. No reports regarding the older PS/2 Type 1 and Type 2 platforms.

Some tips for 5580/5560

Refdisk ver. 1.21 is what you should have. If you have more than 16 MB of RAM in total, you need a reference diskette ver. 1.21 to let the system recognize the installed RAM correctly. (ver. 1.11 for 5561)

Under Win95 the system may report only 16 MB of RAM even if you have more memory installed. To solve this replace HIMEM.SYS that came with Win95 with the one from PCDOS J7.0. This symptom is commonly observed on the other 486 IML machines, but not on EIDE machines such as 5551-R/L and 5530-L.

F/W SCSI-2/A can't be used alone in 5580 with the original complex. Not sure about this issue. It is told that the PS/55 BIOS doesn't contain the required SCSI code (maybe).
   I haven't tested this yet, but it is told that if you want to use F/W SCSI-2/A on 5580, you need to use an usual SPOCK SCSI /A together with F/W SCSI-2/A.

Server Models Other Than 5580

9585, 8595-J with Type 3 M platform and 9595 N/P/Q are the same as the corresponding PS/2s. All models were originally equipped with Japanese ref/diags, but they will accept English ref/diags too.
   Japanese models of 9595 all use the newer 2S2P planar with Type 4 complex installed. No differences can be observed except for the model/type code and the PS/55 badge.

PS/55 Server 85 Brochure
PS/55 Server 95 95A Brochure

Content created and/or collected by:
Louis Ohland, Peter Wendt, David Beem, William Walsh, Tatsuo Sunagawa, Jim Shorney, Tim Clarke, Kevin Bowling, Tomáš Slavotínek, and many others.

Ardent Tool of Capitalism - MAD Edition! is maintained by Tomáš Slavotínek.
Last update: 05 Oct 2022 - Changelog | Legal Info & Contact