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IBM PS/2 Model 25

IBM Personal System/2 Model 25
Personal System 2 Model 25.png
An original PS/2 Model 25
DeveloperInternational Business Machines
ManufacturerIBM
SeriesPersonal System/2
TypePersonal computer
Release dateAugust 4, 1987 (1987-08-04)
Media
  • 720 KB 3.5-in floppy disks (Model 25)
  • 1.44 KB 3.5-in floppy disks (Models 25 286 and 25 SX
CPU
Graphics
Power120/240 VAC ~

The Personal System/2 Model 25 and its later submodels the 25 286 and 25 SX were IBM's lowest-end entries in the Personal System/2 (PS/2) family of personal computers. Like its sibling the Model 30, the Model 25 featured an Industry Standard Architecture bus, allowing it to use expansion cards from its direct predecessors, the PC/XT and the PC/AT—but not from higher entries in the PS/2 line, which used Micro Channel. Unlike all other entries in the PS/2 line, the Model 25 and its submodels were built into an all-in-one form factor, with its cathode-ray tube monitor and system board occupying the same enclosure. IBM oriented the Model 25 at home office workers and students.

Development and release

Case badge on a Model 25 SX

IBM unveiled the Model 25 on August 4, 1987. It was the fifth entry into the Personal System/2 range. The first Model 25 was powered by an Intel 8086 running at 8 MHz, roughly twice the speed of the original IBM Personal Computer. A college student–oriented version of the Model 25, the Collegiate, had two 720 KB floppy drives, maxed out the RAM to 640 KB, and came packaged with the official PS/2 Mouse, Windows 2.0, and four blank floppy disks.

In 1990, IBM released the Model 25 286, which upgraded the original to an Intel 80286 running at 10 MHz. In late 1991, IBM's Boca Raton facility, led by Jose Garcia, developed the Model 25 SX, which featured an Intel 80386SX clocked at 20 MHz. This incarnation of the Model 25 was sold only to K–12 schools. The Model 25 series was never officially sold outside of the United States.

IBM neither included nor supported hard disk drives in the original Model 25, although several aftermarket kits were available by late 1987. The later 25 286 and 25 SX were sold with a hard drive as an option.

Reception

Multiple contemporary reviewers compared the Model 25 to Apple's original Macintosh. Stephen Satchell of InfoWorld wrote when he first saw the Model 25 on its announcement: "[M]y immediate impression was that I was looking at a deformed Macintosh. When the stage lights came up, the illusion was shattered and I saw the similarity to the rest of the PS/2 line."

David E. Sanger of The New York Times called the computer perhaps "the most attractive computer" that IBM had ever designed for people who only used their computer for up to a couple hours a day and while a "touch overpriced", it was "relatively inexpensive for an IBM". Sangler and Gus Venditto of PC Magazine were frustrated by the Model 25's lack of a built-in hard disk drive. Venditto wrote that, on launch, contemporary aftermarket hard drives were too large to modify into either of the computer's two disk drive bays normally reserved for floppies—with no announcements for a hard drive solution for the Model 25 on the horizon. He also observed that the space for the top ISA slot on the riser was partially ensconced by the CRT monitor, preventing full-height cards from fitting into that slot. On the whole, he appreciated the sturdily built chassis and concluded that the Model 25 was a "well-crafted, fast computer for places where real estate is at a premium".

Submodels

IBM PS/2 Model 25 submodels
Model IBM P/N Processor Clock speed
(MHz)
Bus L2 cache
(KB)
No. of
slots
No. of
drive bays
FDD HDD Stock
memory
Monitor Form factor Date introduced Notes Ref(s).
25 8525-001 Intel 8086 8 (0 w) ISA, 8-bit 0 2 2 one 720 KB none 512 KB 12-in. monochrome All-in-one August 1987 Space Saving Keyboard
25 8525-004 Intel 8086 8 (0 w) ISA, 8-bit 0 2 2 one 720 KB none 512 KB 12-in. color All-in-one August 1987 Space Saving Keyboard
25 8525-G01 Intel 8086 8 (0 w) ISA, 8-bit 0 2 2 one 720 KB none 512 KB 12-in. monochrome All-in-one August 1987
25 8525-G04 Intel 8086 8 (0 w) ISA, 8-bit 0 2 2 one 720 KB none 512 KB 12-in. color All-in-one August 1987
25 LS 8525-L01 Intel 8086 8 (0 w) ISA, 8-bit 0 2 2 one 720 KB none 512 KB 12-in. monochrome All-in-one August 1987 Token Ring
25 LS 8525-L04 Intel 8086 8 (0 w) ISA, 8-bit 0 2 2 one 720 KB none 512 KB 12-in. color All-in-one August 1987 Token Ring
25 Collegiate 8525-C02 Intel 8086 8 (0 w) ISA, 8-bit 0 2 2 two 720 KB none 640 KB 12-in. monochrome All-in-one August 1987 Space Saving Keyboard
25 Collegiate 8525-K02 Intel 8086 8 (0 w) ISA, 8-bit 0 2 2 two 720 KB none 640 KB 12-in. monochrome All-in-one August 1987
25 Collegiate 8525-C05 Intel 8086 8 (0 w) ISA, 8-bit 0 2 2 two 720 KB none 640 KB 12-in. color All-in-one August 1987 Space Saving Keyboard
25 Collegiate 8525-K05 Intel 8086 8 (0 w) ISA, 8-bit 0 2 2 two 720 KB none 640 KB 12-in. color All-in-one August 1987
25 286 8525-006 Intel 80286 10 (1 w) ISA, 16-bit 0 2 2 one 1.44 MB none 1 MB 12-in. color All-in-one October 1990 Space Saving Keyboard
25 286 8525-036 Intel 80286 10 (1 w) ISA, 16-bit 0 2 2 one 1.44 MB 30 MB 1 MB 12-in. color All-in-one October 1990
25 286 8525-G06 Intel 80286 10 (1 w) ISA, 16-bit 0 2 2 one 1.44 MB none 1 MB 12-in. color All-in-one October 1990 Space Saving Keyboard
25 286 8525-G36 Intel 80286 10 (1 w) ISA, 16-bit 0 2 2 one 1.44 MB 30 MB 1 MB 12-in. color All-in-one October 1990
25 SX 8525-K00 Intel 80386SX 20 ISA, 16-bit 0 3 2 one 1.44 MB 1 MB 12-in. color All-in-one April 1992
25 SX 8525-K01 Intel 80386SX 20 ISA, 16-bit 0 3 2 one 1.44 MB 1 MB 12-in. color All-in-one April 1992 Ethernet
25 SX 8525-L02 Intel 80386SX 20 ISA, 16-bit 0 3 2 one 1.44 MB 1 MB 12-in. color All-in-one April 1992 Token Ring

This page was last updated at 2022-09-23 06:10 UTC. Update now. View original page.

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