公开(公告)号：DE2855790A1

公开(公告)日：1979-07-12

申请号：DE2855790

申请日：1978-12-22

Applicant: IBM

Inventor： KOSKI JOHN ALEXANDER ,  WEAVER BRUCE RICHARD

IPC: G11B15/02 ,  G11B5/09 ,  G11B15/087 ,  G11B15/44 ,  G11B20/12 ,  G11B27/30 ,  G11B15/06

Abstract: Apparatus and method for controlling a reel-to-reel tape drive so that its performance characteristics are optimized to best suit the operational mode or availability of a host system by modifying tape speed adaptively according to predetermined conditions sensed during processing of data (i.e., while the tape is in motion). For example, tape might initially be fed at a high speed suitable for archiving; but if more than a predetermined number of "backhitches" (overruns of the interblock gap, IBG) occur during processing of a preselected number of successive blocks of data, the host will cause tape speed automatically to be reduced to a lower rate. This lower rate will enable the tape to stop in the IBG and is therefore suitable for intermittent processing. Preferably, before reducing speed during write operations, appropriate signals are generated at the host to command an increase in the IBG from a normal distance to a larger distance if backhitches exceed said preselected number. If this fails to reduce backhitches to an acceptable level, speed will be reduced to the lower rate and the gap preferably restored to its normal distance.