IBM 1401

The IBM 1401 was a transistor- based computer equipped with core memory from IBM. Each core location was directly addressable; the computer worked by a variable length, with which a very efficient use of storage capacity has been reached.

This calculator was introduced on 5 October 1959. It could thus replace tabulating machines like the IBM 407. It was sold to the end of production on 8 February 1971 on 12,000 times. It was also possible to rent the computer from IBM, which in the early 1960s one month's rent of $ 2500 was paid for the basic configuration of the model. The successor product / 3 System was introduced in 1969 on the market.

The computers were originally designed by IBM as a front end for the mainframe 7000 Series. According to IBM, the term Medium Data technology goes back to the introduction of satellite computer IBM 1401 on 5 October 1959.


The IBM 1401, there were different memory configurations (1.4 K, 2K, 4K, 8K, 12K or 16K ). A byte was six bits in length and had a parity bit, an additional bit in the so-called " word mark channel " was used for word boundary ( variable word length).

Punch cards

The 1401 was a pure card system from an IBM 1401 central processing unit, an IBM 1402 card unit for reading ( 800 punch cards / min. ) And cutting (250 punch cards / min. ) Of hole cards, as well as an IBM 1403 printer ( 600 lines / min. ).

Magnetic tape

Magnetic disk

With an attached IBM RAMAC in 1405 it became a magnetic disk system with direct access to 10 up to max. 20000000 alphanumeric characters. Instead of the 1405 RAMAC were from mid 1963 until 6 IBM 1311 disk storage units with interchangeable magnetic disk storage (memory capacity up to 3 million alphanumeric characters) can be connected. In this configuration, the 1401 experienced the most widely used in practice and was, until it was replaced by the IBM 360 computer family is the workhorse in data processing.


The IBM 1401 was freely programmable. The card systems were usually programmed using the symbolic programming language SPS ( Symbolic Programming System). For the more demanding magnetic disk and magnetic tape systems of the IBM 1401 Autocoder in conjunction with the IOPS (Input - Output Control System). There were also quite useful for a FORTRAN compiler and an infrequently used COBOL system.


" RPG: Bridge of the pegboard to the database " heading page 140 describes the transition from the tabulating machine ( Pegboard ) to the Report Generator on the example of the system IBM 1401 page 141 in 1959..