Table 355
+=====-========-========-========-========-========-========-========-========+
| Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
|Byte | | | | | | | | |
|=====+=======================================================================|
| 0 | Operation code (08h) |
|-----+-----------------------------------------------------------------------|
| 1 | Logical unit number | Reserved |
|-----+-----------------------------------------------------------------------|
| 2 | (MSB) |
|-----+--- ---|
| 3 | Allocation length |
|-----+--- ---|
| 4 | (LSB) |
|-----+-----------------------------------------------------------------------|
| 5 | Control |
+=============================================================================+