2Recording Format
Gap Blocks and Gap Tracks
A gap block is a physical block containing 1,024 gap bytes. A gap track is a physical track containing eight gap blocks. When the tape drive stops at the end of a write operation, it writes at least one gap track following the last track containing data blocks. In 8200 or 8200c format, the tape drive writes one gap track. In 8500 or 8500c format, it can write two gap tracks.
The gap track provides the track orientation required to append data. When a subsequent write operation begins, the controller repositions the tape and records the data on a track adjacent to the gap track.
Figure 2-11 shows two tracks, one with seven data blocks and one gap block, and one with a gap track. Gap blocks cannot be accessed by any SCSI command.
7 data blocks
1 gap track
1 gap block
Figure 2-11 One gap block and one gap track in two physical tracks
510504 | ||
| (Standard and XL) |
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