705 Data Processing System

IBM 705 Data Processing System

IBM 705 Data Processing System
Announced October 1, 1954 and withdrawn April 7, 1960.
The IBM 705 was one of the most powerful data processing systems available in the mid-1950s. Operating according to detailed instructions called a program, the 705's electronic circuits performed a series of record-keeping, arithmetic and logical operations automatically and at speeds which made it capable of 240,000 "decisions" in 60 seconds, and of multiplying numbers as large as 1 million at the rate of over 400 per second.

Engineered primarily to handle business data, the 705 could analyze millions of bits of data to determine the optimum location for a retail store; simulate the entire operation of an oil refinery; handle a huge billing operation in minutes; furnish inventory production control reports; or make up a 50,000-employee payroll with millions of deductions.

The usual means of input of data to the 705 system was magnetic tape, but entry could also be effected by a punched card reader, or, when special instructions were required, from the operator's console. At the start of each processing procedure, the program was read into memory from tape or punched cards. Then the machine carried out the entire processing job without human intervention, checking itself for accuracy as it worked. Results could either be printed, recorded on magnetic tape (capacity 5 million characters per reel) or punched into cards. One reel of tape could store the equivalent of 25,000 to 50,000 cards. As many words as the complete text of Gone With the Wind could be duplicated from one magnetic tape to another in 3½ minutes. A 705 at another location could reproduce such reports or figures, using its electronic printers, in a fraction of the time required by any other method.

The computer's memory consisted of tiny ferrite cores strung on frameworks of fine wire. Words, numbers, or instructions were represented by the magnetic or neutral state of groups of cores, and were available for calculation in millionths of a second. This made possible the performance of thousands of calculations per second, and problems which formerly required weeks or months to solve could be handled in a matter of minutes.

The number of units in a data processing machine installation depended on the requirements of the customer. Of the various components in a typical installation, the operator's console, central processing unit, and magnetic tape units were basic.

The following are extracts from a January 1955 edition of the  Manual Of IBM Electronic Data Processing Machines.

Associated equipment
Type Name
705 Central Processing Unit - with Core Memory
714 & 759 Card Reader and Card Reader Control Unit
717 & 757 Printer and Printer Control Unit
722 & 758 Card Punch and Card Punch Control Unit
727 Magnetic Tape Unit
754 Tape Control Unit
734 Magnetic Drum Storage Unit
775 Record Storage Unit

The Type 705 is a large-scale electronic data processing machine controlled by a stored program of the one-address type, utilizing various types of internal storage.

The Type 705 EDPM incorporates many outstanding technological improvements in addition to the basic features of the Type 702. The outstanding features of the Type 705 are:

  1. Magnetic core storage.

  2. Twenty thousand characters of high speed storage.

  3. Increased arithmetic speed.

  4. Added program and logical operations.

  5. Simultaneous read and write features.

  6. Flexible storage arrangement.

  7. Direct memory transfer.

  8. Flexible card reader.

  9. Type 775 Record Storage Unit.

These features of the Type 705 provide increased speed, flexibility and ease of programming.

To insure maximum flexibility, the input-output devices have been designed so that they can be combined, independently of the 705, to provide tape-to-card, card-to-tape, and tape-to-printer operations.

Type 705 Central Processing Unit -- With Core Memory

Features: This unit contains the magnetic core storage and circuits for performing all arithmetic operations and logical decisions.

The Type 705 has 20,000 positions of high-speed magnetic core storage. This doubles the high-speed storage available in the Type 702. Increased high-speed storage will allow longer and more complete programs to be held entirely in storage without the necessity for external communication. The increased capacity, along with the high-speed direct memory transfer, will also permit the handling of larger groups of records, which directly increases tape efficiency.

These features will be of inestimable importance in sorting, internal distributions, manipulation of data transaction files, and other applications involving group records.

The arrangement of the accumulator and the auxiliary storage units in the Type 705 has been made more flexible. One accumulator of 256 positions, one auxiliary storage unit of 32 positions, and 14 auxiliary storage units of 16 positions each are furnished.

The use of magnetic core storage permits a character cycle rate of 17 microseconds. In addition to this, the 705 has the ability to read and interpret instructions in a single character cycle (17 microseconds). This enables the 705 to increase its ability to read and interpret its instructions by a factor of almost seven with respect to the 702.

Operator's console: The operator's console is a separate unit, but is considered an integral part of the Central Processing Unit of the 705. The console is used to:

  1. Control the machine manually.

  2. Store information manually.

  3. Determine the status of registers and counters.

  4. Display the contents of memory and storage.

Typewriter: The typewriter on the Type 705 can be used to print directly from memory, one character at a time. The speed of typing is approximately 600 characters per minute. All other operations of the machine are held up during the typing operation.

The typewriter has a 12" carriage and is equipped with a pin feed platen. Maximum length of writing line is 8 7/8", overall form width 9 7/8", and hole-to-hole dimension is 9 3/8".

Any character not on the code chart prints as a question mark. A plus zero and a minus zero print as a plus sign and a hyphen respectively. Sensing the record mark automatically causes a carriage return and automatic spacing in accordance with the setting of the space control on the carriage.

Main power supply: The main power supply is furnished as a separate unit of the 705 and supplies the necessary regulated power for the operation of the Central Processing Unit.