The IOCC_ADAPTER_PASSTHRU CommandCode consists of all the CommandModifiers responsible for issuing SCSI-formatted requests to a unit. The following table describes the CommandModifiers:

┌────────────────────────┬────────────────────────────────────┐
│CommandModifier         │Description                         │
├────────────────────────┼────────────────────────────────────┤
│IOCM_EXECUTE_SCB        │Issues an IBM Subsystem Control     │
│                        │Block (SCB) request to the specified│
│                        │unit.                               │
│                        │Support of this command is optional.│
├────────────────────────┼────────────────────────────────────┤
│IOCM_EXECUTE_CDB        │Issues a SCSI Command Descriptor    │
│                        │Block (CDB) request to the specified│
│                        │unit.                               │
│                        │This command is mandatory for all   │
│                        │SCSI units.                         │
└────────────────────────┴────────────────────────────────────┘

Remarks