6 Functional Specifications
Write Reliability
Write reliability is determined by the rate of permanent write errors. During a write operation, the tape drive uses
If the tape drive can rewrite the data block correctly, the error is a temporary write error, which does not affect write reliability. If, however, the tape drive cannot rewrite the data block correctly after a maximum of 11 rewrite attempts (12 write attempts total), the error is a permanent write error. When a permanent write error occurs, the tape drive returns Check Condition status.
The rate for permanent write errors is as follows:
Bit error rate: 1.0
Read Reliability
Read reliability is determined by the rate of permanent read errors. If, during a read operation, the tape drive cannot read a block that has been correctly written, it attempts to reread the block. The tape drive keeps track of the number of times it attempts to reread a block and stores this number internally. This number is available through the REQUEST SENSE (03h) command and the LOG SENSE (4Dh) command.
If the tape drive can reread the data block correctly, the error is a temporary read error, which does not affect read reliability. If, however, the tape drive cannot reread the data block correctly after one reread attempt at normal speed and one reread attempt at slow speed, the error is a permanent read error. When a permanent read error occurs, the tape drive returns Check Condition status.
The rate for permanent read errors is as follows:
Bit error rate: 1.0
May 1994 | ||
| (Standard and XL) |
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