GB1369384A - Data storage apparatus - Google Patents

Abstract

1369384 Selective signalling INTERNATIONAL BUSINESS MACHINES CORP 31 Oct 1972 [1 Nov 1971] 50053/72 Headings G4H and G4A Data storage apparatus comprises a shift register operable to store a series of codes and having input and output stages interconnected to form a closed loop, the series including two sections of character-representing codes divided from one another by a separator code, each section being further subdivided by controlling codes, decoding means to detect the controlling and separator codes passed between the input and output stages, and gating means operable, in response to the decoding means, to gate character codes to a data receiving means alternately from the two sections under the control of the controlling and separator codes. The shift register is N bits wide. Its output feeds the decoding means and can be fed via a first buffer register, a normal register, an insert register and a second buffer register back to the input of the shift register, though usually the insert register is by-passed. Both the normal and the insert registers can be by-passed. A data buss connected to a printer and keyboard, and to a record reader, can be fed from the first buffer register and can feed the second buffer register. One of the two sections of the series of codes can include an operation code, defining the section as that which has to be addressed for reading or writing of codes, the other section containing a hold code. The two sections can hold respective texts entered from cards or by keying, and which have to be merged and printed out. A section button specifies whch section is to be addressed, and if this is inconsistent with the specification provided by the hold and operation codes these are automatically interchanged. Assuming then that the section with the operation code is being addressed for print-out, readout for printing starts at the operation code and continues (with movement of the operation code along the series as successive codes are output) until a switch code is encountered when the operation and hold codes are interchanged and read-out continues from the new position of the operation code (i.e. in the other section) until another switch code is encountered when the system returns to the first section in the same way, and so on. Print out can be stopped by stop codes in the sequence, when the operator can cause it to continue in the other section using the section button. A clear button can be used to clear either section.