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# 12 Hole Paper Tape - CSIRAC Computer, Logarithim Base Two, T120, 1955-1964Reg. No: HT 13509 5

Summary:
Paper tape, part of a collection of paper tape programs and sub-routines used for input to CSIRAC. This tape contains three sub-routines, each a self contained unit designed to carry out a specific task within a program.

This tape was originally stored in Box B101 of the CSIRAC Program Library, which consisted of tried and tested paper tape programs and sub-routines (sections of programs). The tape is now stored with the other paper tape programs originally stored in box B101. The tapes stored in box B101 were T002.2, T120, T121, T122 and T123.

The collection includes the original University of Melbourne Computation Laboratory Paper Tape Library of 12 hole tapes of subroutines and programs, and program and data tapes from staff and outside users.
Most of the paper tapes were 12-track punched paper tapes. 5 hole paper tapes were used primarily for data input and output rather than program input. However, 5 hole program tapes could be produced by using Interprogram, an English language programming system rather than using machine language.

Each tape has a 'T' number. The Computation Laboratory Paper Tape Library consisted of tapes with a tape number less than 700. There were not 700 tapes but the number 700 was arbitrarily chosen to separate the Computation Laboratory Library tapes from user tapes.

Details of this tape:
Tape No: T120 Box No: B101
08.Transcendental 3 Routines For T120.2&.3, entry at 1 gives log(AB) if AB > 2 to the -32
This tape contains 3 subroutines for the calculation of the logarithm to base 2 of the number in the A register.
T120.1 A` = log 2A = 1 + log A A >= 1/2
T120.2 A` = (1/32) log A
T120.3 A` = -(1/32) log A
For the last two, entry at 1 gives log (AB) if AB exceeds 2^-32
For more documentation on the contents of this tape see folder 8, inventory id HT13511.12
Acquisition Information:
Donation from University of Melbourne (The) Computer Science & Software Engineering Department
 Discipline: Technology