IBM Portable Personal Computer

IBM Portable PC Computer 5155 model 68
An IBM Portable PC, with the aftermarket addition of a 3.5" floppy diskette drive, which would have been an addition to the system or a replacement for one of the 5.25" drives.
Developer IBM
Type Portable computer
Release date February 1984 (1984-02)
Discontinued April 1986 (1986-04)[1]
Operating system IBM PC DOS Version 2.10 (disk)
CPU Intel 8088 @ 4.77MHz
Memory 256 kB (expandable to 512 kB)
Storage One or two half-height ​5 1⁄4" 360 kB floppy disk drives
Display CGA card connected to an internal 9 inch monochrome (amber) composite monitor
Weight 30 pounds (13.6 kg)
Predecessor IBM Personal Computer
Successor IBM PC Convertible

The IBM Portable Personal Computer 5155 model 68 was an early portable computer developed by IBM after the success of the suitcase-size Compaq Portable. It was released in February, 1984, and was quickly replaced by the IBM Convertible, only roughly two years after its debut.

Design

The Portable was basically a PC/XT motherboard, transplanted into a Compaq-style luggable case. The system featured 256 kilobytes of memory (expandable to 512 kB on the motherboard), an added CGA card connected to an internal monochrome amber composite monitor, and one or two half-height ​5 1⁄4" 360 kB floppy disk drives, manufactured by Qume. Unlike the Compaq Portable, which used a dual-mode monitor and special display card, IBM used a stock CGA card and a 9" amber monochrome composite monitor, which had lower resolution. It could, however, display color if connected to an external monitor or television. A separate 83-key keyboard and cable was provided, which uses a phone jack styled connector.

Experts stated that IBM developed the Portable in part because its sales force needed a computer that would compete against the Compaq Portable.[2] If less sophisticated than the Compaq, the IBM had the advantage of a lower price tag. The motherboard had eight expansion slots. The power supply was rated 114 watts and was suitable for operation on either 120 or 230 VAC.[1] Hard disks were a very common third-party add-on as IBM did not offer them from the factory.[1] Typically in a two-drive context, floppy drive A: ran the operating system, and drive B: would be used for application and data diskettes.

Its selling point as a "portable" was that it combined the monitor into a base unit approximating a medium-sized suitcase that could be simply set on its flat side, the back panel slid away to reveal the power connector, plugged in, the keyboard folded down or detached, and booted up for use, though printers at the time, if needed, still tended to be less "portable". At thirty pounds, it may have been difficult to carry for some.

References

  1. 1 2 3 Scott Mueller, Upgrading and Repairing PCs, Second Edition, Que, 1992 ISBN 0-88022-856-3 pp. 76–81
  2. ↑ Rosenberg, Ronald (1984-02-28). "Doubts Raised About PCjr". The Boston Globe.
Notes

  • IBM (1984). Personal Computer Hardware Reference Library: Guide to Operations, Portable Personal Computer. IBM Part Numbers 6936571 and 1502332.
Preceded by
IBM Personal Computer		 IBM Personal Computers Succeeded by
IBM PC Convertible
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