M2488 PRODUCT GUIDE TAPE PROCESSING
April 1997 CG00000-011503 REV. A 7-3
7-3 PERMANENT ERRO R HANDLING
Basic operating procedures, such as rewind and unload, are described in Chapter 5 of the User’s Guide.
7-3.1 PERMANENT WR ITE ERROR
If a permanent write error occurs, the most common error recovery method is to attempt to re-write
the data, on the failing media, with a different tape drive. Here are the steps to perform this error
recovery:
1) Issue a READ POSITION command, with the BT bit set to 1b (34 01 ... 00), to find out the
following four things:
• First Block Location
• Last Block Location
• Number of Blocks in Buffer
•Number o f Bytes i n Buffer
2) Use the RECOVER BUFFERED DATA command to retrieve and save the data from the
buffer. Several RECOVER BUFFERED DATA commands may be needed to retrieve all
buffered write blocks. The READ POSITION data will tell you the number of blocks and
bytes in the buffer.
3) REWIND and UNLOAD the cartridge from this tape drive.
4) LOAD the cartridge into a different tape drive.
5) Issue a LOCATE command to position to the end of the last record on the tape. The value to
use for the LOCATE blockid is the READ POSITION Last Block Location field.
This field indicates the physical position of the tape. The value in this field is the block
address of the next block to be transferred between the buffer and the [tape] medium.
6) WRITE the recovered data. If the write error occurs again, it is possible that the media in the
cartridge is so badly worn, or damaged, that it is not possible to write on the tape.
Other things to try:
• If you determine that the tape is worn/damaged, then replace the cartridge and re-write
the data on the new cartridge.
•If you only have one tape drive, you can attempt the previous procedure with a cleaning
cycle performed between steps three (3) and four (4).
•The drive may need to be cleaned. If you are not sure how to clean the tape drive, then
contact your product support representative for more information.
• Contact your product support representative for more information about additional
recovery procedures.
7-3.2 PERMANENT RE AD ERROR
Two common causes of permanent read errors are worn/damaged media and dirty tape drive heads
and/or tape path. The procedure to recover from a permanent read error is similar to the procedure for
recovery from a permanent write error:
1) Issue a READ POSITION command, with the BT bit set to 1b (34 01 ... 00), to find out the
following four things:
• First Block Location
• Last Block Location
• Number of Blocks in Buffer
•Number o f Bytes i n Buffer
2) REWIND and UNLOAD the cartridge from this tape drive.
3) LOAD the cartridge into a different tape drive.