A magnetic tape auxiliary memory for the digital computer at TIFR

SummaryThe magnetic tape auxiliary memory provides for an additional storage capacity of 256,000 words. The data transfer instructions transfer only single character at a time and so a word or a block of words can be transferred only by use of programmed sub-routines. The zone search instructions provide for the automatic selection of the required section of the magnetic tape and for switching the tape heads to read or write mode as instructed. Any section of the tape is available for reading information from or writing information on to it. The search can proceed both in the forward and reverse direction and the programmer has not to trouble himself about rewinding of tapes. These features are in contrast with other tape systems where the whole of the magnetic tape is available for read only or write only purpose and where the tape scanning can take place only by starting at the initial end of the tape spool. The scheme for data transfer is quite flexible and block transfers need not be only of 256 words; they could be of larger or smaller capacity provided the parameter indicating the number of words is suitably changed in the transfer sub-routine. A complete safety of the magnetic tape and the information is guaranteed by suitable control circuitry.