Log Sense - X'4D'
The Log Sense command is supported by the tape library. Table 1 shows the command format.
| Byte | Bit 7 MSB |
Bit 6 | Bit 5 | Bit 4 | Bit 3 | Bit 2 | Bit 1 | Bit 0 LSB |
|---|---|---|---|---|---|---|---|---|
| 0 | Operation code (X'4D') | |||||||
| 1 | LUN (Obsolete) | Reserved | PPC (B'0') | SP (B'0') | ||||
| 2 | PC | Page Code | ||||||
| 3 | Reserved | |||||||
| 4 | Reserved | |||||||
| 5-6 | Parameter Pointer | |||||||
| 7-8 | Allocation Length | |||||||
| 9 | Vendor Specific (B'00') | Reserved (B'0000') | Flag (B'0') | Link (B'0') | ||||
The following tape library-specific parameters apply:
- PPC: Parameter pointer control.
- SP: Save parameters.
- PC: Page control. The following values apply:
B'00' Threshold Values. Supported for all log pages with log counters (the LP field is set to B'0' in the Log Parameter Control Byte). B'01' Cumulative Values. Supported for all log pages. B'10' Default Threshold Values. Supported for all log pages with log counters. The default threshold value for all 2-byte log counter-fields is X'FFFF'. The default threshold value for all 4-byte log counter-fields is X'FFFF FFFF'. B'11' Default Cumulative Values. Not supported. The default cumulative value for all 2-byte log counter-fields is X'0000'. The default cumulative value for all 4-byte log counter-fields is X'0000 0000'. - Page Code: Indicates the log page to be returned.
- Parameter Pointer: Indicates the starting log page parameter code to be returned for this
request. Parameters will be returned in ascending order up to the maximum allocation length or the
maximum parameter code, whichever is less. A parameter pointer of X’0000’ returns parameter data
starting with the first parameter code.
The parameter pointer is supported for Log Page X’30’ only. For all other log pages the parameter pointer must be set to X‘0000’.
The log pages that are supported for the Log Sense command are: