Artifact Details

Title

IBM 709 Data Processing System CPU

Catalog Number

102728984

Type

Physical object

Description

This object is part of the 709 system donated by Paul Pierce. Height includes small counter box on top of machine.

IBM 709 was a vacuum tube, mainframe, scientific computer introduced in 1957. It was designed to solve complex problems in commercial and scientific areas at high speed. It performed logical operations as well as fixed and floating point arithmetic and logical operations. Fixed point addition, subtraction and logical operations were performed at 42,000 per second (24 microseconds). However multipliction or division operations were performed at 4000 per second (240 microseconds). Floating point operations were much slower. Addition and subtraction operations were performed at 12,000 per second (84 microseconds). A multipliction operation was performed at 4500 per second (216 microseconds).

The memory subsystem was made up of magnetic cores. Each memory word was 36 bits wide with a capacity of 4096, 8192 or 32,768 words. A memory cycle to read or write a word took 12 microseconds.

The IBM 709 design included multiple innovations including tape drive and index register functionality.

Three index registers provided automatic counting and address modification. One peculiarity of the index registers was that there were three, selected by a 3-bit field in the instruction, each register being selected by one bit; if more than one bit was set, the registers indicated were logically OR-ed together before being used.

To improve tape reliability, a two-gap tape head was introduced. One head wrote the information to the tape while the second head read the information just written. This feature made it possible to verify the information on the tape was correct.

It is remarkable to compare a current (2022) consumer PC to the IBM 709. An AMD 7700x based consumer pc has a clock cycle of 4.5 GigaHertz (4,500,000,000) and can execute 4 instructions per cycle. This is 18,000,000,000 operations per second (222 picoseconds) or about 500,000 times faster than the IBM 709. The AMD based consumer PC cost about $1000. The IBM 709 system cost about $2,600,000. The PC uses about 200 Watts. The IBM 709 used about 200 Kilowatts.

The IBM 709 computer was discontinued in April 1960. It was replaced by the transistorized IBM 7090 computer.

Date

1958

Manufacturer

International Business Machines (IBM)

Identifying Numbers

Model number 709
Other number 120458 On dial on small counter unit on top of machine, under the heading "POWER".
Other number 41767 On dial on small counter unit on top of machine, under the heading "EXECUTION".

Dimensions

overall: 69 in x 34 1/2 in x 72 1/2 in

Category

Digital computer/mainframe

Collection Title

Paul Pierce Collection

Credit

Gift of Paul Pierce

Lot Number

X7021.2014