IBM Portable PC 5155
Model:model 68
Introduced:February 1984
Price: US $4225.
Weight:30 pounds
CPU:Intel 8088 @ 4.77MHz
RAM:256K, 640K max
Display:9-inch amber display
CGA graphics, 80 X 25 text
Storage:Two 360KB 5.25-inch disk drives
Ports:1 parallel, 1 serial, CGA video
OS: IBM PC-DOS Version 2.10 (disk)





Excerpt from the original IBM announcement:

The IBM Portable Personal Computer 5155 Model 68 consists of a lightweight case with a carrying handle containing a built-in. 9-inch, amber composite display, one 5 1/4-inch double sided diskette drive (with space for an optional second drive), and two IBM Personal Computer attachment options (diskette adapter and colour/graphics adapter).

The unit also has a new, lightweight keyboard and a universal power supply. The system board is the same as that of the IBM Personal Computer XT with 256Kb of memory that is expandable to 512Kb using the memory expansion option.

Five expansion slots are available for the connection of most IBM Personal Computer options. The system has identical function and performance characteristics to an equivalently configured IBM Personal Computer.



The Portable is not really a new, redesigned IBM computer, it's actually just the same motherboard as the IBM XT (model 5160) desktop system installed in a carry-around case with a built-in monitor and floppy drives.

Because of this, the eight internal expansion slots aren't quite as useful as they could be. The floppy drives take-up a lot of room, so most of the slots cannot accept full-length cards:

Slot Max length Card installed
1 13 inch Video Controller
2 13 inch empty
3 10 inch Disk controller
4 5 inch Parallel port
5 5 inch Async (serial)
6 5 inch empty
7 4 inch empty
8 4 inch empty



It's considered portable, but only because of the built-in monitor and drives. There are no batteries, you still have to plug it into the 110VAC outlet.

The 5155 was IBM's response to the Compaq Portable computer, which was released one year prior, costs $700 less, but has the same CPU and runs just as fast. The Compaq was advertised as being 100% IBM compatible, and even weighs slightly less.

This wasn't IBM's first portable computer, that would be the IBM 5100, released in 1975 - It was revolutionary, and extremely expensive.

Related Links

  • IBM 5155 from IBM of Canada
  • QUE: Upgrading & Repairing PCs Eighth Edition

    • Partial History of the IBM Computers

    • 1967: IBM builds the worlds first floppy disk.
    • 1967: IBM introduces the worlds first 8" floppy disk.
    • 1973: IBM introduces the IBM 3340 hard disk unit, known as the Winchester.
    • 1975: September - IBM's Entry Level Systems unit unveils "Project Mercury", the IBM 5100 Portable Computer.
    • 1981: September - IBM ships the IBM 5150 PC Personal Computer.
    • 1982: April - Eight months after the introduction of the IBM PC, 50,000 units have been sold.
    • 1982: May - Microsoft releases MS-DOS 1.1 to IBM, for the IBM PC.
    • 1982: June - The first IBM PC clone, the MPC, is released by Columbia Data Products.
    • 1982: August - After one year of production, IBM ships the 200,000th IBM PC.
    • 1982: November - Compaq Computer introduces the Compaq Portable PC, the first 100% IBM compatible. It cost Compaq US$1 million to create an IBM-compatible ROM BIOS that did not violate IBM's copyright.
    • 1982: At the West Coast Computer Faire, Davong Systems introduces its 5MB Winchester Disk Drive for the IBM PC, for US$2000.
    • 1983: March - IBM announces the IBM PC XT, with a 10 MB hard drive, 128KB RAM and a 360KB floppy drive. It costs US$5000.
    • 1983: November - IBM announces the IBM PCjr. It is US$700 for the bare configuration.
    • 1984: February - IBM introduces the IBM Portable PC.
    • 1984: March - IBM ships the IBM PCjr. It uses the 8088 CPU, 64KB RAM, and one 5.25-inch disk drive, but no monitor. It costs US$1300.
    • 1984: August - IBM announces the PC AT, for US$4000-6700.
    • 1985: April - IBM abandons production of the IBM PCjr.
    • 1986: April - IBM announces the IBM PC Convertible, 80C88-based, 256K RAM, and two 720K floppy disks, for US$2000.
    • 1986: April - IBM discontinues the IBM Portable PC.
    • 1986: September - IBM announces the IBM PC-XT Model 286, with 640KB RAM, 1.2MB floppy drive, 20MB hard drive, serial/parallel ports, and keyboard for US$4000.
    • 1987: IBM discontinues the IBM PC (model 5150) line.
      Source: Chronology of Events in the History of Microcomputers



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