Mode Sense (10) - X'5A'

The Mode Sense (10) command is supported by the tape library. Table 1 shows the command format.

Table 1. Mode Sense (10) Command
Byte Bit 7


Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0


0 Operation code (X'5A')
1 LUN (Obsolete) Reserved DBD Reserved
2 PC Page Code
3 Reserved
4 Reserved
5 Reserved
6 Reserved
7 Allocation Length
9 Vendor Specific (B'00') Reserved (B'0000') Flag (B'0') Link (B'0')

The following tape library-specific parameters apply:

  • DBD: Disable block descriptors. Supported values are B'0' or B'1'.
  • PC: Page control. Supported values are B'00', B'01', or B'10'.
  • Page Code: Supported values are X'18', X'1C', X'1D', X'1E', X'1F', X'20', and X'3F' (return all pages).
  • Allocation Length: The maximum number of bytes to be transferred. If the allocation length specified is less than the amount available, then the allocated amount is transferred and no error is reported.
The following mode pages are supported by the tape library. For more detail, go to each "Related Reference."
  • Mode Page X'18': Fibre Channel Logical Unit Control Page (Fibre Channel control paths only)
  • Mode Page X'1C': Informational Exceptions Control
  • Mode Page X'1D': Element Address Assignment
  • Mode Page X'1E': Transport Geometry Parameters
  • Mode Page X'1F': Device Capabilities
  • Mode Page X'20': VU Mode Parameters Page