Browse Prior Art Database

Full-Track Staging

IP.com Disclosure Number: IPCOM000100385D
Original Publication Date: 1990-Apr-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 1 page(s) / 33K

Publishing Venue

IBM

Related People

Berger, BH: AUTHOR [+2]

Abstract

The commands for full-track staging can be determined by the detection of either the index or the no-sync-no-data signals together with a read home address command. If an index or no-sync-no-data signal is encountered before a count field, the controller is activated to read the home address in order to stage the entire track for transfer to another memory store.

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This is the abbreviated version, containing approximately 100% of the total text.

Full-Track Staging

       The commands for full-track staging can be determined by
the detection of either the index or the no-sync-no-data signals
together with a read home address command.  If an index or
no-sync-no-data signal is encountered before a count field, the
controller is activated to read the home address in order to stage
the entire track for transfer to another memory store.

      Roll-mode reads are the quickest method to accomplish the goal
of staging an entire track from a direct access storage device (DASD)
to another memory store.  Roll-mode read commands connect the DASD to
the controller as soon as possible, and the data from the track is
immediately branched until the entire track is in the second memory,
such as a cache store.  A roll-mode read is independent of the track
orientation of the DASD.  Formerly, the controller read a record and
continued reading until the entire track from the DASD had been
staged into the second memory store; a count field signal and an
index signal had to be read before the transfer could be made.

      Performance can be improved by activating the read home address
command when an index or a no-sync-no-data signal have been detected.
 Therefore, if an index signal or a no-sync-no-data signal is
encountered before a count field is sensed, the controller activates
the read command to permit the transfer from the home address to the
next index signal.