The CSIRAC Program library consisted of tried and tested paper tape programs and sub-routines (sections of programs).
A wooden "pigeon hole" cabinet was located on the program preparation desk in the Computation Laboratory and used as the storage location for the Program Library. The library programs were numbered and stored in individual cardboard boxes. The Library only contained 12 hole paper tapes.
The Program Library was built up in order to make the writing of programs more efficient. The Library consisted of previously written, tested sub-routines or programs designed to perform common functions. Programmers could incorporate copies of required library sub-routines, like building blocks, into their own program. This avoided the necessity of each programmer having to create new sub-routines for common functions every time a new program was developed.
The Library was started in 1956 and was added to on a continuous basis until 1964.
Official CSIRAC Library Tapes were identified with an extra line of holes, and were kept in labelled boxes.
Many tapes were produced by users but were not part of the official Paper tape Library. They were left in the Library Pigeon Holes for convenience. A number of tapes did not have any identification and are listed as unknown. 'T#' was used to identify tapes. The CSIRAC History team in the 1990s found tapes inside tapes; these were given suffixes eg T001.1
John Spencer was creator and sole user for all tapes in the range T800 to T893 (except tapes T807 and T849 to 854 inclusive).
Tapes numbered T>800 are dated 1959-1964.
Programs and sub-routines related to the teleprinter were written up to and including 1960.
Programs and sub-routines related to the flexowriter were written after and including 1959.