Patent GB-886889-A (GB)
Title: Improvements in memory systems for data processing devices
IPC: G06F9/32
Filed: 1959-08-07
Abstract: 886,889. Transferring digital data between stores. INTERNATIONAL BUSINESS MACHINES CORPORATION. Aug. 7, 1959 [Aug. 29, 1958], No. 27141/59. Class 106 (1). Information words are transferred between tape units 1 to 6 and core storage 16 under the control of an instruction word which causes transfer of a selector record control word to a register, the record control word indicating the addresses of the information words. Initially programme instruction words, tape instruction words and record control words are loaded into sequential locations of core storage 16. The address of the first instruction is set up in counter 36 which then causes the instruction to be read to programme register 24 while the counter is advanced by one. A so-called scatter read or write operation which involves transfer of information from or to the tape units is initiated by a tape instruction word, Fig. 4. This is passed to the programme register 24 and the operation digits, in the 0, 1 positions, interpreted in operation matrix 33 which signals tape control unit 10 to prepare timing and interlock. An initial status word, Fig. 5, is then assembled in B buffer register 13 to which input and output is in parallel. The address in counter 36 is passed to B-register 13 to form positions 2 to 5 of the initial status word. Positions 4 and 5 of the tape instruction word in programme register 24 are passed to an operation and tape drive unit 21 which functions to select a particular tape drive unit and the operation to be performed, the operation code is passed to position 1 of B-register 13. Additionally, the sign and the contents of positions 0, 1 and 6 to 8 of programme register 24 are transferred via bus 15 to B-register 13 to complete the initial status word. The word is then transferred to core storage at an address determined by the central address generator 78. A read scatter operation is continued by taking the record control work, Fig. 2, at the address defined by positions 6 to 9 of the tape instruction word and transferring its sign to register 73, its start address to register 52 and its stop address to register 53. Information from the tape is then translated from 7 bit to 2 out of 5 code and read serially into A-register 12. It is then transferred in parallel to B-register 13 and from there to the address in core storage specified by the start address. At each entry the start address is incremented and a compare operation on the start and stop addresses performed. When equality is reached a test signal is gated by a signal from the compare unit to the sign register 73. If the sign is positive location register 75 issues the address of a new record control word, if negative the scatter operation ceases and a final status word is assembled. Tape control issues a condition digit on line 7a to position 1 of the B-register, the address contained in start register 52 is transferred to positions 2 to 5, the address of the last record control word is transferred to positions 6 to 9 and its sign to the sign position. Unit 21 is analysed and a signal issued to central address generator 78 which specifies the location in store to which the final status word will be transferred from the B-register. A write scatter operation takes much the same form, transferring information from core storage to the tape reels, and is not described in detail in the Specification.