Browse Prior Art Database

Data Processing Initialization

IP.com Disclosure Number: IPCOM000075917D
Original Publication Date: 1971-Dec-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 47K

Publishing Venue

IBM

Related People

Edstrom, GH: AUTHOR [+2]

Abstract

In some programmed digital machines, working registers LSR-10 store signals having program implications. Parity verifies correctness of the readout signals. When power is turned on in a machine, the signal content of LSR-10 is random including parity relationships. In low-cost devices, proper parity in LSR-10 may be required before an operating program can be initiated. It may or may not be important that LSR-10 have appropriate information content, in so long as parity is correct. On the other hand, LSR-10 may have certain registers which should contain all zeroes but with proper parity.

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Data Processing Initialization

In some programmed digital machines, working registers LSR-10 store signals having program implications. Parity verifies correctness of the readout signals. When power is turned on in a machine, the signal content of LSR-10 is random including parity relationships. In low-cost devices, proper parity in LSR- 10 may be required before an operating program can be initiated. It may or may not be important that LSR-10 have appropriate information content, in so long as parity is correct. On the other hand, LSR-10 may have certain registers which should contain all zeroes but with proper parity. In such low-cost machines, control memory (CM) 12 may be a read-only memory or may be loaded in an electrically alterable memory which maintains the code permutations even though power is turned off, such as a disc, drum, and the like.

While separate program routines could be located in CM 12 for the initialization process, it is more efficient to initialize LSR-10 while verifying other portions of the machine. A good time to initialize LSR-10 is during a content verifying scan of registers in CM 12. Such an operation can be done for selected portions of CM 12 and selected portions of LSR-10, in accordance with the following teachings.

Generation of a start signal, either by automatic or manual means, sets scan FF 14 to the active condition and simultaneously initiates operation of machine clock 16. Scan FF 14 indicates that CM 12 is being scanned for proper readout and that LSR-10 is being conditioned for proper parity. CM 12 being scanned by instruction counter (IC) 18 supplies instruction words to register 20. Such instruction words are ve...