My Computer Collection
IBM PS/2 Model 65SX

Photo of IBM PS/2 Model 65SX
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Similar to the 55SX following the Model 50, the Model 65SX was the successor of the Model 60. With Intel's newly introduced 386SX processor, it was a way to run 32-bit software in a cheap, 286-like environment (if you like to call any of the PS/2's 'cheap'...). In contrast to the 55SX, IBM didn't redesign the case - you can swap boards between the 60 and 65SX.

Photo of IBM PS/2 Model 65SX's innards
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Another difference between the 55SX and the 65SX is the hard disk interface: There is no ESDI disk, the machine was directly shipped with the new SCSI busmaster adapter and SCSI hard disks of either 60 or 120MB. Compared to EDSI, this was a nice improvement both in speed and functionality. IBM continued to use SCSI as hard disk interface throughout the rest of the PS/2 line, with the exception of some late Model 76/77 that had an IDE interface.

Closeup of IBM PS/2 Model 65SX's Planar
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Common to the 55SX is the memory subsystem. The 65SX has 2 sockets, which can be filled with 1/2/4 MByte modules, giving 8 Mbytes of on-board memory. However, the required 4M/80ns modules have a different presence detection code than the 70ns modules used in later PS/2's, so a module pulled e.g. out of a 56 or 76 won't work unless you modify the presence detection solder bridges. See Peter Wendt's pages for a description of the presence detection codes.

Processor:
i386SX @ 16 MHz
Coprocessor:
i387SX @ 16 MHz
Cache:
none
Memory:
14 Mbytes (on-board options from 2..8M)
Bus:
8 MCA slots (16 bit)
Interfaces (onboard):
  • Mouse, Keyboard
  • 1x Serial
  • 1 x Parallel
  • Floppy (1.44M), allows attachment of up to 2 drives
  • VGA
Add-on cards:
  • Novell NE/2 Ethernet Card
  • IBM 2-8MB Memory Expansion
  • IBM SCSI Controller
  • IBM Graphics Adapter 8514/A
Operating System(s):
  • Caldera OpenDOS 7.01
  • OS/2 Warp 3
  • Linux 2.2 (Slackware-based)
Useful Links:


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©1999 Alfred Arnold, alfred@ccac.rwth-aachen.de