Browse Prior Art Database

File Scan within Limits

IP.com Disclosure Number: IPCOM000095123D
Original Publication Date: 1965-Sep-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Evans, JR: AUTHOR

Abstract

The circuitry scans the contents of a bulk core storage unit CS 2 for a record or a message which falls within an upper and a lower limit. Usually a record in a CS 2 is scanned for high, low or equal condition with a desired scan mask. This arrangement permits scanning within specified limits or on an equal condition.

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File Scan within Limits

The circuitry scans the contents of a bulk core storage unit CS 2 for a record or a message which falls within an upper and a lower limit. Usually a record in a CS 2 is scanned for high, low or equal condition with a desired scan mask. This arrangement permits scanning within specified limits or on an equal condition.

Prior to executing this scan instruction, the scan mask is set up. The high and low limits on which the scan is to be made are placed in their respective registers 6 and 8. If the scan is for an equal condition, the high and low limits are the same. The starting address of the scan is specified in the scan instruction and is loaded into the address register AR 10. As each byte of data is read from the file, it is compared with the contents of both limit registers. Simultaneously with the comparison, the byte read from CS 2 is placed in the core memory of CPU
12. The comparison continues until the record area to be scanned is exhausted. Reading continues until the end of record indication is detected.

If the specified limits are not encountered within the record area scanned, AR 10 is reset to the beginning of scan address. The system then waits until the beginning of the next record is detected.

Additional records are scanned in a similar manner. The scan continues until the record within specified limits is encountered or until the end of scan signal is detected. If the record is encountered which falls within the limit spec...