A desktop Micro Channel machine built around the 386SX, the cut-down chip that gave 386 instructions on a 16-bit bus. That combination made it IBM's volume business PS/2 and a common OS/2 workstation, so surviving examples often carry period software and adapters. The 55 SX is the easiest way into Micro Channel: small enough to shelve, plentiful enough to be affordable, and it takes the same reference-diskette configuration dance as its larger relatives.

Details

Manufacturer	IBM
Model	PS/2 Model 55SX
Year	1987
Form factor	proprietary
Chassis	desktop
CPU	386SX-16
Installed RAM	2× 2MiB 72-pin (4 MiB)
Drives	Custom 2.88MB Gotek
OS	MS DOS 6.22
Condition	Restored
Source	Knock Knock Old Geek, Discord
Acquired	2026-05-16
Reference	https://en.wikipedia.org/wiki/IBM_PS/2_Model_55_SX

Machine

Catalogue model	PS/2 Model 55 SX (8555) — IBM PS/2, 1989

Motherboard

RH-0238 · Motherboard

IBM PS/2 Model 55SX

Chipset

IBM 90X8134 IBM 23F9177 IBM 27F4619 IBM 23F8566 IBM 27F4620 IBM 27F465

CPU family

386-class

Form factor

proprietary

RAM slots

2× 72-pin SIMM

Slots

3× MCA

BIOS

IBM C1.10 (1988)

Onboard video

IBM VGA

Ports

Floppy, Serial, Parallel, PS/2 keyboard, PS/2 mouse

Parts

1

RH-0239 · Storage

IBM 6128260

Kind

Hard disk

Interface

ESDI

Protocol

ESDI

Capacity

120 MiB

CHS

115/64/32

Files

No files for this one yet.

History

2026-08-21	summary: The Personal System/2 Model 55 SX is a midrange desktop computer in IBM's Perso… → (empty)
2026-08-19	variant: (empty) → PS/2 Model 55 SX (8555)
2026-07-30	cpu: 386 SX 16 → 386SX-16