IBM Portable Personal Computer

The IBM Portable Personal Computer 5155 model 68 is 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.

IBM Portable PC 5155 model 68
An IBM Portable PC with two 5.25-inch floppy diskette drives installed
TypePortable computer
Release dateFebruary 1984; 40 years ago (1984-02)
Introductory priceUS$4,225 (equivalent to $12,390 in 2023)
DiscontinuedApril 1986 (1986-04)[1]
Operating systemIBM PC DOS Version 2.10 (disk)
CPUIntel 8088 @ 4.77 MHz
Memory256 KB (expandable to 640 KB)
StorageOne or two half-height 5+14-inch 360 KB floppy disk drives
DisplayCGA card connected to an internal 9-inch monochrome (amber) composite monitor
Mass30 pounds (13.6 kg)
PredecessorIBM Personal Computer
SuccessorIBM PC Convertible

Design edit

The Portable was basically a PC/XT motherboard, transplanted into a Compaq-style luggable case. The system featured 256 kilobytes of memory (expandable to 640 KB), an added CGA card connected to an internal monochrome amber composite monitor, and one or two half-height 5+14-inch 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-inch 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 front panel mounted phone jack styled connector RJ11. The cable from the connector then went to the back of the machine, where the original XT keyboard jack was.

Experts [who?] 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 115 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, and was often referred to as "luggable".

Timeline edit

Timeline of the IBM Personal Computer
IBM ThinkCentreIBM NetVistaIBM Palm Top PC 110IBM PC SeriesIBM AptivaIBM PS/ValuePointThinkPadEduQuestIBM PS/noteAmbra Computer CorporationIBM PCradioIBM PS/1IBM Industrial SystemIBM PS/55IBM PS/2IBM Personal Computer XT 286IBM PC ConvertibleIBM JXIBM Personal Computer AT/370IBM Personal Computer ATIBM Industrial ComputerIBM PCjrIBM Portable Personal ComputerIBM Personal Computer XT/370IBM 3270 PCIBM Personal Computer XTIBM 5550IBM Personal ComputerIBM System/23 DatamasterIBM 5120IBM 5110IBM 5100
Asterisk (*) denotes a model released in Japan only

References edit

  1. ^ a b c 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.
  • IBM (1984). Personal Computer Hardware Reference Library: Guide to Operations, Portable Personal Computer. IBM Part Numbers 6936571 and 1502332.

External links edit