Browse Prior Art Database

Disk Search Technique

IP.com Disclosure Number: IPCOM000080235D
Original Publication Date: 1973-Nov-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 58K

Publishing Venue

IBM

Related People

Harboe, RW: AUTHOR [+2]

Abstract

A device for recording a series of records on parallel cylinders or tracks of a recording media in ascending order to form a file, is provided with a search technique for identifying a record or partial record without manual intervention after an appropriate mask is entered. The search will start at the first record of the file when initiated from the index track, and at the current address when initiated within the file. The search increments the current address and ends at the last record position in the file. If the record was not found a "no record found" error is posted. Where the search is initiated at the end of the file, another error will be posted indicative of the condition that no search was made.

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Disk Search Technique

A device for recording a series of records on parallel cylinders or tracks of a recording media in ascending order to form a file, is provided with a search technique for identifying a record or partial record without manual intervention after an appropriate mask is entered. The search will start at the first record of the file when initiated from the index track, and at the current address when initiated within the file. The search increments the current address and ends at the last record position in the file. If the record was not found a "no record found" error is posted. Where the search is initiated at the end of the file, another error will be posted indicative of the condition that no search was made.

The search contains two subroutines. One reads a record at a time while the other reads three records at a time. The former subroutine is entered if the current disk address sector does not equal one when the search is initiated, or when current disk address cylinder is the last cylinder of the file. The latter subroutine is entered when the current disk address sector is one and the current cylinder being addressed is prior to the last cylinder of the file. The latter subroutine will queue three reads from a 26 sector disk, respectively, to an X buffer, a Y buffer and a Z buffer, starting with the first, ninth and eighteenth records on the first pass. The respective buffers receive the second, tenth and nineteenth records on the second...