SPACE | 6.Command Specification |
6.27.SPACE 11h
Bit | 7 | 6 | 5 | 4 |
| 3 | 2 | 1 | 0 | |
Byte |
|
|
|
|
|
|
|
|
|
|
0 |
|
|
|
| Operation | Code (11h) |
|
|
| |
1 |
|
|
| Reserved |
|
|
|
| Code |
|
2 | (MSB) |
|
|
|
| Count |
|
|
| |
3 |
|
|
|
|
|
|
|
| ||
4 |
|
|
|
|
|
|
|
|
| (LSB) |
5 |
|
|
|
|
| Control |
|
|
| |
The SPACE command provides a variety of positioning functions that are determined by the Code and Count fields in the CDB. Both forward (toward EOM/P) and reverse (toward BOM/P) positioning are provided.
Code: The supported values are:
| Table | |
|
|
|
Code |
| Description |
000b |
| Blocks |
001b |
| Filemarks |
011b |
| EOD |
100b |
| Setmarks |
Note: The drive will reject a SPACE Setmark command if it has not configured through MODE SELECT to report Setmarks. The drive will return a CHECK CONDITION status with the Sense Data set to ILLEGAL REQUEST. In this command description the word “mark” is used to mean Filemark or Setmark. Only where their responses differ Filemark and Setmark will be referred explicitly.
Count: When spacing over blocks or marks, the Count field is interpreted as follows:
A positive value N causes forward movement over N blocks or marks. The tape is logically positioned after the Nth block (or mark) on the EOM/P side.
A ZERO value causes no change in the logical position.
A negative value
When spacing to EOD, the Count field is ignored. Forward movement occurs until the drive encounters EOD.
When executing a SPACE, the drive implements the following hierarchy: Blocks (lowest), Filemarks, Setmarks, EOD, BOM/P or EOM/P (highest)
Therefore, SPACE N blocks command will terminate with GOOD status after the Nth block, or with a CHECK CONDITION status on any occurrence of Filemark, Setmark, EOD, BOM/P or EOM/P. SPACE N Filemarks will halt on the Nth Filemark or on any occurrence of Setmark, EOD, BOM/P or EOM/P, and so on. Within the Sense Data, the fields will be set as described on the following table.
SONY |
