IBM 5110

The IBM 5110 Portable Computer was the successor of the IBM 5100 Portable Computer.

Three variations of the IBM 5110 were built:

IBM 5110 Model 1 (with a built-in QIC DC300 tape drive of 204 kB).
IBM 5110 Model 2 (without the QIC tape drive).
IBM 5110 Model 3 - also designated as the IBM 5120 (with two built-in 8 inch 1.2 MB floppy disk drives).
The IBM 5110 was announced in January 1978 (3 years after the introduction of the IBM 5100). Its main differences were support for more I/O devices (floppy disk drives, IEEE-488, RS232, ...) and a character set (EBCDIC) which was compatible with other IBM machines. These improvements made it partially incompatible with the IBM 5100.

The 5110 featured the same housing as the 5100 (although the colors were different), which contained a central processing unit, a keyboard and a 1,024-character display screen. Main memory held 16, 32, 48 or 64 KiB of data, depending on the unit. Offering either magnetic tape or diskette storage, the Model 1 could store as much as 204,000 bytes of information per tape cartridge or 1.2 million bytes on a single diskette; the Model 2 allowed only diskette storage. Up to two IBM 5114 diskette units, each housing a maximum of two diskette drives, could be attached to the 5110 for a total online diskette capacity of 4.8 million bytes. The IBM 5110 Model 3 allowed only one external IBM 5114 diskette unit.

An IBM 5103 printer and an external IBM 5106 auxiliary tape unit (Model 1 only) were available as options.

Citing the easy use of his new system, Jeff Grube, vice president of Punxsutawney Electric Repair (who received the first IBM 5110 on February 2, 1978), said: "If you can type and use a hand-held calculator, you have all the skills necessary to operate a 5110."