Browse Prior Art Database

Variable IBG Mode for Tape Drive

IP.com Disclosure Number: IPCOM000050543D
Original Publication Date: 1982-Nov-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Recupero, AA: AUTHOR

Abstract

A method of obtaining a high speed streaming operation on a start/stop tape drive is described. The normal mode of obtaining a high performance operation on a tape drive is to use what is generally referred to as streaming mode. In a streaming-mode operation, the tape speed is increased with no attempt to stop in the gap between records. Instead, if the tape drive is not instructed within the proper amount of time to write another record, the drive enters a time-consuming reorientation mode, referred to as a back hitch, which is designed to reposition the read/write element to maintain the normal gap between the records.

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Variable IBG Mode for Tape Drive

A method of obtaining a high speed streaming operation on a start/stop tape drive is described. The normal mode of obtaining a high performance operation on a tape drive is to use what is generally referred to as streaming mode. In a streaming-mode operation, the tape speed is increased with no attempt to stop in the gap between records. Instead, if the tape drive is not instructed within the proper amount of time to write another record, the drive enters a time-consuming reorientation mode, referred to as a back hitch, which is designed to reposition the read/write element to maintain the normal gap between the records.

A new mode of operating a tape drive is suggested, in addition to start/stop mode, for use when a disk file is being dumped to the tape drive. This mode may be referred to as a variable interblock gap mode (IBG) in that a relatively slow speed, such as 25 inches per second or 50 inches per second, tape drive which is designed to start and stop in its normal gap at its rated speed is caused to run at a much higher speed, for example, 125 inches per second. In this new mode, after writing a block, the read/write element enters the gap as usual. If the tape drive receives a reinstruct signal within the proper time, the normal nominal gap is traversed and the next block of data is written. If, however, the tape drive does not receive the next instruction within the preestablished window, then the drive starts to decel...