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Shortening Method of Wrap Change Time by Adjusting Head and Tape Movement Time Dynamically on Tape Drive

IP.com Disclosure Number: IPCOM000013545D
Original Publication Date: 2001-Jun-01
Included in the Prior Art Database: 2003-Jun-18
Document File: 3 page(s) / 61K

Publishing Venue

IBM

Abstract

Disclosed is a method to shorten wrap change time on tape drive by optimizing backhitch process at the End Of Wrap. In order to achieve the goal, the method adjusts tape transfer time for tape length direction to comply with the head move time for tape width direction. Tape Edge G uard B and 24 2526272829303234Tape Edge G uard B and Direction for Tape Length

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  Shortening Method of Wrap Change Time by Adjusting Head and Tape Movement Time Dynamically on Tape Drive

Disclosed is a method to shorten wrap change time on tape drive by optimizing
backhitch process at the End Of Wrap. In order to achieve the goal, the
method adjusts tape transfer time for tape length direction to comply with the
head move time for tape width direction.

Tape Edge G uard B and

242526272829303234Tape Edge G uard B and

Direction for Tape Length

Wrap

Figure 1. Head Move

Figure 1 shows the head movement. There are five servo bands for Tape Width
direction that are used to identify the head position of both tape width
direction and tape length direction. Four data bands where user data is
written are located between these servo bands.

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36384547Servo B and 0

Servo B and 1

Servo B and 2

Servo B and 3

Servo B and 4

3940414244Data Band 3

Data Band 1

Data Band 0

3335Data Band 2

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Head

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Tape Speed

+V TS

-V TS

Figure 2. Head position on tape and tape speed during tape movement

Figure 2 shows the relation between head position down the length of the tape
and the tape speed. When a head starts moving, the transition state is
changed from Wait to Locate Accel to accelerate the tape speed. If the tape
speed reaches to the target speed, the state is changed to Locate Cruise. If
the head has already got to the target data band when it gets to the
destination, the drive can start writing or reading data on the tape.
Otherwise, the drive starts backhitch process to wait the head to get to the
target data band. The state keeps Locate Coast until...