The IBM Portable Personal Computer 5155 model 68 is an early

portable computer A portable computer is a computer designed to be easily moved from one place to another and included a display and keyboard together, with a single plug, much like later desktop computers called '' all-in-ones'' (AIO), that integrate the sy ...

developed by IBM after the success of the suitcase-size

Compaq Portable The Compaq Portable was an early portable computer which was one of the first IBM PC compatible systems. It was Compaq Computer Corporation's first product, to be followed by others in the Compaq Portable series and later Compaq Deskpro series. ...

. It was released in February 1984 and was quickly replaced by the

IBM Convertible The IBM PC Convertible (model 5140) is a laptop computer made by IBM, first sold in April 1986. The Convertible was IBM's first laptop-style computer, following the luggable IBM Portable, and introduced the 3½-inch floppy disk format to the IBM ...

, only roughly two years after its debut.

Design

The Portable was basically a

PC/XT The IBM Personal Computer XT (model 5160, often shortened to PC/XT) is the second computer in the IBM Personal Computer line, released on March 8, 1983. Except for the addition of a built-in hard drive and extra expansion slots, it is very simila ...

motherboard, transplanted into a Compaq-style luggable case. The system featured 256

kilobyte The kilobyte is a multiple of the unit byte for digital information. The International System of Units (SI) defines the prefix ''kilo'' as 1000 (103); per this definition, one kilobyte is 1000 bytes.International Standard IEC 80000-13 Quantiti ...

s of memory (expandable to 640 KB), an added CGA card connected to an internal monochrome amber

composite monitor A composite monitor or composite video monitor is any analog video display that receives input in the form of an analog composite video signal to a defined specification. A composite video signal encodes all information on a single conductor; a ...

, and one or two half-height -inch 360 KB

floppy disk A floppy disk or floppy diskette (casually referred to as a floppy, or a diskette) is an obsolescent type of disk storage composed of a thin and flexible disk of a magnetic storage medium in a square or nearly square plastic enclosure lined w ...

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 phone jack styled connector

RJ11 A registered jack (RJ) is a standardized telecommunication network interface for connecting voice and data equipment to a service provided by a local exchange carrier or long distance carrier. Registration interfaces were first defined in the ...

. The cable from the connector then went to the back of the machine, where the original XT keyboard jack was. Experts stated that IBM developed the Portable in part because its sales force needed a computer that would compete against the Compaq Portable. 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. Scott Mueller, ''Upgrading and Repairing PCs, Second Edition'', Que, 1992 pp. 76–81 Hard disks were a very common third-party add-on as IBM did not offer them from the factory. 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”.

References

;Notes * IBM (1984). ''Personal Computer Hardware Reference Library: Guide to Operations, Portable Personal Computer''. IBM Part Numbers 6936571 and 1502332.

External links

Obsolete Technology Website: IBM Portable PC 5155 model 68

IBM 5155 information at www.minuszerodegrees.net
{{IBM personal computers 5155 Portable Portable computers Computer-related introductions in 1984