SCSI Format Unit Command
The SCSI Format Unit command is used to format a SCSI target device into LBAs. Defect management options can be specified in the CDB. This command can take a very long time to complete, typically one or more hours.
The CDB structure is:
Bit |
0 |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
|---|---|---|---|---|---|---|---|---|
+0 |
Operation Code = 0x04 |
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+8 |
LUN |
FmtData |
CmpLst |
Defect List Format |
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+16 |
Vendor-specific |
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+24 |
Interleave |
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+32 |
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+40 |
Control |
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The special parameter fields in the CDB have the following meaning:
- FmtData - Format Data - if this is one then the command is followed by two or three extra parameters:
- defect list header -
- initialization pattern descriptor -
- defect descriptors (optional) -
- CmpLst - Complete List:
- 0 - the initiator will send a partial list of defects, to be added to the existing list
- 1 - the initiator will send a complete list of defects, overwriting the existing list
- Defect list format - if the FmtData bit is one then this describes the defect options:
- 000 - block format - 32-bit LBAs
- 100 - bytes from index format - cylinder + head + byte-offset
- 101 - physical sector format - cylinder + head + sector
- 110 - vendor-specific
- Interleave -
- 0000h - the target can use its default interleave
- 0001h - consecutive LBAs must be contiguous
- all other values are vendor-specific