The IBM 1401 Symbolic Programming System (SPS) was an assembler that was developed by the Applied Programming Department of IBM as an alternative to the use of machine code

Machine code

Machine code or machine language is a system of impartible instructions executed directly by a computer's central processing unit. Each instruction performs a very specific task, typically either an operation on a unit of data Machine code or machine language is a system of impartible instructions...

 for the IBM 1401

IBM 1401

The IBM 1401 was a variable wordlength decimal computer that was announced by IBM on October 5, 1959. The first member of the highly successful IBM 1400 series, it was aimed at replacing electromechanical unit record equipment for processing data stored on punched cards...

 computer, the first of the IBM 1400 series

IBM 1400 series

The IBM 1400 series were second generation mid-range business decimal computers that IBM sold in the early 1960s. They could be operated as an independent system, in conjunction with IBM punched card equipment, or as auxiliary equipment to other computer systems.1400-series machines stored...

. One source indicates that "This programming system was announced by IBM with the machine.". As the 1400 series matured it acquired additional memory options (from the initial 4000, increasing to 16000 characters) and SPS was replaced by the "Autocoder

Autocoder

Autocoder was the name given to certain assemblers for a number of IBM computers of the 1950s and 1960s.The first Autocoders appear to have been the earliest assemblers to provide a macro facility....

" language in most installations.

Both Autocoder and SPS were assembly language

Assembly language

An assembly language is a low-level programming language for computers, microprocessors, microcontrollers, and other programmable devices. It implements a symbolic representation of the machine codes and other constants needed to program a given CPU architecture...

s using mnemonic

Mnemonic

A mnemonic , or mnemonic device, is any learning technique that aids memory. To improve long term memory, mnemonic systems are used to make memorization easier. Commonly encountered mnemonics are often verbal, such as a very short poem or a special word used to help a person remember something,...

s as a substitute for programming directly in machine language

Machine code

Machine code or machine language is a system of impartible instructions executed directly by a computer's central processing unit. Each instruction performs a very specific task, typically either an operation on a unit of data Machine code or machine language is a system of impartible instructions...

. A copy of the IBM 1401 Autocoder specifications including mnemonic operation codes is preserved at bitsavers.org.

External links

• http://www.bitsavers.org/pdf/ibm/140x/C24-1480-0_1401symbPgmSys.pdf IBM 1401 Symbolic Programming Systems: SPS-1 and SPS-2, C20-1480-0
• "1401s I have known" by Tom Van Vleck
  Tom van Vleck
  -Life and work:He worked on CTSS at MIT, and co-authored its first email program.In 1965, he joined Project Mac, which is the origin of the MIT Computer Science and Artificial Intelligence Laboratory., Chiou, Stefanie; et. al...
  
  includes a description of an operating environment including both early, SPS, and later Autocoder 1401 machines.
• An Encyclopedia of Computer Languages article entitled "Autocoder III" preserves information from the 1961 announcement of Autocoder programming capabilities for the expanded, 4,000 positions of core memory, IBM 1401.