Personal System / 2

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IBM PS / 2 Model 55 SX
IBM PS / 2 Model 70 (8570-121) MCA motherboard

The Personal System / 2 is a series of personal computers introduced by IBM in 1987 , which was intended to replace the previous system of the IBM PC .

architecture

Outstanding features were the 32- bit -based system bus Microchannel , which was supposed to replace the ISA bus, the Intel 80386 processor, new possibilities in the graphic area ( VGA , 8514 / A and XGA ) and the "intelligent" power supply. For the first time, IBM installed 3.5 ″ floppy disk drives with a capacity of 1.44 MB (later with up to 2.88 MB) in a PC-compatible system , which initially caused confusion because on the previous models (IBM PC) 5 .25 "floppy disks were common, but no 5.25" drive was offered for the PS / 2 models. The ESDI and SCSI hard disk connection replaced the early ST506 interface of the IBM-PC XT and IBM-PC AT with significantly better mass storage options.

Market situation

The new system offered a lot of advantages, but was e.g. B. not compatible with old expansion cards or floppy disks and extremely expensive. PC-DOS , the new OS / 2 or even the Unix derivative AIX could be chosen as operating systems . IBM patented the microchannel and large parts of the system and demanded high license payments from manufacturers who wanted to offer a PS / 2-compatible system themselves in order to prevent their own computers from being displaced from the market by replicas, as is the case with PCs was.

The competition led by Compaq rebelled; this company already had a system based on the Intel 386 on offer, but it was equipped with the old ISA slots. The PS / 2 could not establish itself because of only moderate success. The necessary speed for the IO area was upgraded in the PC replicas with new, open interfaces ( EISA , VESA Local Bus and later PCI ). The microchannel disappeared completely from the market in 1995 with the last PS / 2.

The overestimated success had consequences, IBM had lost its market power in the PC area, henceforth unconditional downward compatibility also on the hardware level was the top priority in the PC area. After the PS / 2 models, IBM brought the PS / ValuePoint series onto the market - these computers were among others. a. with AT bus significantly more compatible with the original IBM PC models. Ultimately, however, IBM gave the segment to Lenovo in 2005 .

The PS / 2 connections for input devices are still reminiscent of the PS / 2 systems , which for reasons of compatibility were found on every motherboard for a long time , but have now been replaced by USB , as well as the designation of the PS / 2 memory socket -SIMM , which was used in most 486 and Pentium systems.

The different PS / 2 models

With ISA bus

  • PS / 2 Model 25 , a low-performance workstation computer with an integrated monitor (technically more an IBM PC XT with Intel 8086 or 80286 processor)
  • PS / 2 Model 30 , the entry-level model at the time (like Model 25, more of a PC XT than a PS / 2)
  • PS / 2 Model 35 , SX or LS as a network client
  • PS / 2 Model 40 , an entry-level solution
  • PS / 2E , a mini-desktop derived from a laptop. The internal IBM name is # 9533. Its dimensions are only 70 mm × 305 mm × 305 mm. Its main technical features are: IBM 486SLC2 @ 25/50 MHz, max. 16 MB RAM and 160 MB 2.5 ″ IDE hard disk . Since the IBM 486SLC2 has the bus interface of the 386SX, the RAM limit of 16 Mbytes is low for a “real” 486. A 387SX can be added as an option. In contrast to most of the early PS / 2 models, it does not have an MCA but an ISA bus (only one slot). The ISA slot was delivered from the factory with an adapter for 16/4 Token Ring , Ethernet 10BASE-T or 4-way PCMCIA . Instead of using the IDE hard disk, you can also boot using storage media in the PCMCIA adapter (memory card or hard disk). Other laptop similarities are a compact keyboard with integrated Trackpoint II and a laptop-like power management. The supported operating systems are DOS with Windows 3.1, OS / 2 and AIX.

With microchannel

  • PS / 2 Model 50, popular desktop computer with 80286 processor
  • PS / 2 Model 55, flat desktop computer with 80386SX processor
  • PS / 2 Model 56, compact desktop computer with IBM 486SLC2 processor
  • PS / 2 Model 57, workstation computer
  • PS / 2 Model 60, entry-level server with 80286 processor
  • PS / 2 Model 65, entry-level server with 80386SX processor
  • PS / 2 Model 70, an average workstation computer
  • PS / 2 Model 77 Multimedia, a computer designed for the multimedia wave of that time with CD-ROM drive, video processing card and sound card as standard
  • PS / 2 Model 80, the first IBM computer with an Intel 80386 processor, designed as a high-performance workstation or workgroup server
  • PS / 2 Model 90, a high performance workstation with XGA graphics
  • PS / 2 Server 85, entry-level server
  • PS / 2 Server 95, server with the 486 or Pentium processor
  • PS / 2 Server 195, medium network server
  • PS / 2 Server 295, large network server
  • PC Server 720, large network server with 7 microchannel / PCI slots and up to 6 CPUs

Mobile calculator

  • PS / 2 Model P70 , a portable computer with a 386SX processor and plasma screen
  • PS / 2 Model P75 , with 486 processor (November 30, 1990)
  • PS / 2 L40SX , a portable device (1991)
  • PS / 2 Note N33SX , a notebook with a 386SX processor (1992)
  • Thinkpad 700 and 700C
  • PS / 2 Note N51SX , a typical notebook

Operating systems for PS / 2

literature

  • Martin Ernst, Detlef Grell : debut: Big Blues first 80386 computer - IBM PS / 2 model 80 - c't 12/87, p. 64
  • Jim Hoskins: IBM Personal System / 2: Description, Use, Application, Technical Details , Vieweg 1987, ISBN 3-528-04419-5

Web links

Individual evidence

  1. ↑ http://incolor.inebraska.com/jshorney/p70.htm