Artifact Details

Description

This object is an IBM 5100 Portable Computer. In 1975, it was announced as IBM's first "Portable Personal Computer". Two other models were introduced: the IBM 5110 in 1978 and the IBM 5120 in 1980. The IBM 5110 was organized as a traditionl computer with a desktop processor and external peripherals. The IBM 5120 was organized like the IBM 5100 but in a larger chassis with two 8" floppy disc drives instead of a tape drive. The IBM 5100 series was not a big seller. It was superseded by the IBM 5150 - the IBM PC in 1981.

For its time, the IBM 5100 had the unique feature of integrating everything you needed into one housing. A processor, memory, a 5" CRT monitor, a 1/4 inch tape drive with capacity of 200KB, a keyboard, and optionally a BASIC and/or A Programming Language (APL) interpreter were combined in one unit. Main memory was expandable from 16KB to 64kB.

The processor has a 15.1MHz oscillator that generates 66.2ns clock pulses. A machine cycle is 8 clock pulses long or 530ns . Instructions can take one to three machine cycles. The processor is 16 bits, but the Arithmetic-Logic Unit (ALU) is 8 bits. Thus a 16 bit arithmetic operation required two passes through the ALU. The processor is microprogrammed, with the microprogram stored in the "Control ROS" (Read Only Storage).

The resolution of the CRT monitor is 16 lines of 64 characters. It can display normal text or the first 512 bytes of main memory and CPU registers during operation. A switch on the front panel selects the display mode.

The back connector panel has space for connectors for two serial interfaces, an IEEE-488 interface, a matrix printer with either 80 or 120 characters per line and another external tape drive. The tape drive connectors are arranged in a unique triangular pattern. If these connectors were not used, a screw on cover with signal line terminators was used.

Date

1975

Manufacturer

International Business Machines Corporation (IBM)

Identifying Numbers

Model number	5100
Other number	10-1046 on back of computer
Other number	105 on serial number plate on bottom of computer
Other number	143-054	143-054 on Arthur D. Little Asset Tag on side of computer
Serial number	10416

Dimensions

overall: 8 x 17.5 x 24

Category

Digital computer/personal computer/desktop