IBM PS/2 Model 25

The Personal System/2 Model 25 and its later submodels the 25 286 and 25 SX are 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 features 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 use Micro Channel. Unlike all other entries in the PS/2 line, the Model 25 and its submodels are built into an all-in-one form factor, with its cathode-ray tube (CRT) monitor and system board occupying the same enclosure. IBM oriented the Model 25 at home office workers and students.^[2]

Personal System/2 Model 25

An original PS/2 Model 25
Developer	International Business Machines Corporation (IBM)
Manufacturer	IBM
Product family	Personal System/2
Type	Personal computer
Release date	August 4, 1987; 37 years ago (1987-08-04)
CPU	Intel 8086 at 8 MHz (Model 25) Intel 80286 at 10 MHz (Model 25 286) Intel 80386SX at 20 MHz (Model 25 SX)
Graphics	Multi-Color Graphics Array (Model 25)[1] Video Graphics Array (Models 25 286 and 25 SX)
Power	120/240 VAC ～
Related	List of IBM PS/2 models

Development and release

Case badge on a Model 25 SX

IBM unveiled the Model 25 on August 4, 1987. It is the fifth entry of the Personal System/2 range. The first Model 25 is powered by an Intel 8086 running at 8 MHz, roughly twice the speed of the original IBM Personal Computer.^[3] A college student-oriented version of the Model 25, the Collegiate, has two 720 KB floppy drives, with a maximum RAM capacity of 640 KB, and was packaged with the official PS/2 Mouse, Windows 2.0, and four blank floppy disks.^[4]

In 1990, IBM released the Model 25 286, which upgrades the original to an Intel 80286 running at 10 MHz.^[5] In late 1991, IBM's Boca Raton facility, led by José García, developed the Model 25 SX, which features an Intel 80386SX clocked at 20 MHz. This version of the Model 25 was sold only to K–12 schools.^[6] The Model 25 series was never officially sold outside of the United States.^[7]

IBM neither included nor supported hard disk drives in the original Model 25, although several aftermarket kits were available by late 1987.^[8] The later 25 286 and 25 SX were sold with a hard drive as an option.^[7][9]

Reception

Multiple contemporary reviewers compared the Model 25 to Apple's original Macintosh.^[2][10][11] 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."^[4]

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."^[2] Sangler and Gus Venditto of PC Magazine were frustrated by the Model 25's lack of a built-in hard disk drive.^[2][11] Venditto wrote that, on launch, contemporary aftermarket hard drives were too large to be installed in either of the computer's two floppy drive bays—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 is partially obstructed 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."^[11]

Submodels

See also: List of IBM PS/2 models

IBM PS/2 Model 25 submodels

Model	IBM P/N	Processor	Clock speed (MHz)	Bus	No. of slots	No. of drive bays	FDD	HDD	Stock RAM	Maximum RAM	Video adapter	Monitor	Form factor	Date introduced	Notes	Ref(s).
25	8525-001	Intel 8086	8 (0 w)	ISA, 8-bit	2	2	one 720 KB	none	512 KB	640 KB	MCGA	12-in. monochrome	All-in-one	August 1987	Space Saving Keyboard	[12]
25	8525-004	Intel 8086	8 (0 w)	ISA, 8-bit	2	2	one 720 KB	none	512 KB	640 KB	MCGA	12-in. color	All-in-one	August 1987	Space Saving Keyboard	[12]
25	8525-G01	Intel 8086	8 (0 w)	ISA, 8-bit	2	2	one 720 KB	none	512 KB	640 KB	MCGA	12-in. monochrome	All-in-one	August 1987		[13]
25	8525-G04	Intel 8086	8 (0 w)	ISA, 8-bit	2	2	one 720 KB	none	512 KB	640 KB	MCGA	12-in. color	All-in-one	August 1987		[13]
25 Collegiate	8525-C02	Intel 8086	8 (0 w)	ISA, 8-bit	2	2	two 720 KB	none	640 KB	640 KB	MCGA	12-in. monochrome	All-in-one	August 1987	Space Saving Keyboard	[14]
25 Collegiate	8525-C05	Intel 8086	8 (0 w)	ISA, 8-bit	2	2	two 720 KB	none	640 KB	640 KB	MCGA	12-in. color	All-in-one	August 1987	Space Saving Keyboard	[14]
25 Collegiate	8525-K02	Intel 8086	8 (0 w)	ISA, 8-bit	2	2	two 720 KB	none	640 KB	640 KB	MCGA	12-in. monochrome	All-in-one	August 1987		[14]
25 Collegiate	8525-K05	Intel 8086	8 (0 w)	ISA, 8-bit	2	2	two 720 KB	none	640 KB	640 KB	MCGA	12-in. color	All-in-one	August 1987		[14]
25 LS	8525-L01	Intel 8086	8 (0 w)	ISA, 8-bit	2	2	one 720 KB	none	512 KB	640 KB	MCGA	12-in. monochrome	All-in-one	August 1987	Token Ring	[13]
25 LS	8525-L04	Intel 8086	8 (0 w)	ISA, 8-bit	2	2	one 720 KB	none	512 KB	640 KB	MCGA	12-in. color	All-in-one	August 1987	Token Ring	[13]
25 286	8525-006	Intel 80286	10 (1 w)	ISA, 16-bit	2	2	one 1.44 MB	none	1 MB	4 MB	VGA	12-in. color	All-in-one	October 1990	Space Saving Keyboard	[15]
25 286	8525-036	Intel 80286	10 (1 w)	ISA, 16-bit	2	2	one 1.44 MB	30 MB (ST-506)	1 MB	4 MB	VGA	12-in. color	All-in-one	October 1990		[15]
25 286	8525-G06	Intel 80286	10 (1 w)	ISA, 16-bit	2	2	one 1.44 MB	none	1 MB	4 MB	VGA	12-in. color	All-in-one	October 1990	Space Saving Keyboard	[15]
25 286	8525-G36	Intel 80286	10 (1 w)	ISA, 16-bit	2	2	one 1.44 MB	30 MB (ST-506)	1 MB	4 MB	VGA	12-in. color	All-in-one	October 1990
25 SX	8525-K00	Intel 386SX	20	ISA, 16-bit	3	2	one 1.44 MB	none	1 MB	16 MB	VGA	12-in. color	All-in-one	April 1992		[6][9]
25 SX	8525-K01	Intel 386SX	20	ISA, 16-bit	3	2	one 1.44 MB	none	1 MB	16 MB	VGA	12-in. color	All-in-one	April 1992	Ethernet	[6][9]
25 SX	8525-L02	Intel 386SX	20	ISA, 16-bit	3	2	one 1.44 MB	none	1 MB	16 MB	VGA	12-in. color	All-in-one	April 1992	Token Ring	[6][9]

References

1. Sandler, Corey; Donald Kennedy (1989). Insider's Guide to the IBM PS/2. Scott Foresman. p. 66. ISBN 9780673381712 – via Google Books.
2. Sanger, David E. (August 9, 1987). "I.B.M. Learns from the Macintosh". The New York Times: A12 – via ProQuest.
3. Hillkirk, John; Mark Lewyn (August 4, 1987). "Tandy, IBM target school, home market". USA Today. Gannett Company: 1B – via ProQuest.
4. Satchell, Stephen (August 17, 1987). "Short Looks: IBM PS/2 Model 25". InfoWorld. 9 (33). IDG Publications: 44 – via Google Books.
5. Marburg, Robert (December 24, 1990). "IBM debates AT-bus PS/2 plans for '91". PC Week. 7 (51). Ziff-Davis: 6 – via Gale.
6. Lunan, Charles (January 1992). "IBM Goes After School Computer Market". Sun Sentinel. Tribune Publishing Company. p. D3 – via ProQuest. On Tuesday, IBM released the first product developed by [Jose] Garcia's team: the Model 25 SX. The new model uses the same Intel 386SX microprocessor ... to run the graphics-rich software popular with teachers. It will be able to display up to 256 different colors and come standard with connections for overhead projection systems and computer networks. IBM said the new models would become available in April at $1,249 to $1,899.
7. Staff writer (May 11, 1990). "IBM adds pricey 80286-based PS/2 model 25 in US". Computergram International (1423). GlobalData – via Gale.
8. Willmott, Donald P. (December 8, 1987). "Hard Disk Power for the Model 25". PC Magazine. 6 (21). Ziff-Davis: 328 – via Google Books.
9. Walsh, William (June 15, 2005). "IBM PS/2 Model 25SX". Walsh Computer Technology. Retrieved September 29, 2021.
10. Freiberger, Paul; John Markoff (October 13, 1987). "Apple's Mac emerges as most influential PC". Montreal Gazette: G1 – via ProQuest.
11. Venditto, Gus (September 29, 1987). "PS/2 Model 25 Looks Like a Mac, Runs Like a Model 30". PC Magazine. 6 (16). Ziff-Davis: 33–34 – via Google Books.
12. "IBM PS/2 (Model 25) – Technical Specifications". International Business Machines Corporation. 2000. Retrieved September 28, 2021 – via Ardent Tool.
13. "IBM Personal System/2 and IBM Personal Computer Product Reference, Version 4.0" (PDF). International Business Machines Corporation. September 1988. p. 44. Retrieved September 29, 2021 – via Bitsavers.
14. "IBM Personal System/2 and IBM Personal Computer Product Reference, Version 4.0" (PDF). International Business Machines Corporation. September 1988. p. 43. Retrieved September 29, 2021 – via Bitsavers.
15. "IBM PS/2 (Model 25-286) – Technical Specifications". International Business Machines Corporation. 2000. Retrieved September 28, 2021 – via Ardent Tool.

External links

IBM Personal System/2 Model 25 a booklet brochure.