---
title: fCommandDescriptorBlock
framework: scsiperipheralsdriverkit
role: symbol
role_heading: Instance Property
platforms: [driverkit 22.0+]
path: scsiperipheralsdriverkit/scsideviceoutparameters/fcommanddescriptorblock
---

# fCommandDescriptorBlock

A 16-byte opcode to fill out the Command Descriptor Block (CDB).

## Declaration

```occ
SCSICommandDescriptorBlock fCommandDescriptorBlock;
```

## Discussion

Discussion Populate this member of the parameters structure with the functions listed in the following sections: Creating common SCSI commands Creating Self-Monitoring, Analysis and Reporting Technology (SMART) Commands Creating arbitrary SCSI commands

## See Also

### Setting command parameters

- [fLogicalUnitNumber](scsiperipheralsdriverkit/scsideviceoutparameters/flogicalunitnumber.md)
- [fTimeoutDuration](scsiperipheralsdriverkit/scsideviceoutparameters/ftimeoutduration.md)
- [fRequestedByteCountOfTransfer](scsiperipheralsdriverkit/scsideviceoutparameters/frequestedbytecountoftransfer.md)
- [fBufferDirection](scsiperipheralsdriverkit/scsideviceoutparameters/fbufferdirection.md)
- [fDataTransferDirection](scsiperipheralsdriverkit/scsideviceoutparameters/fdatatransferdirection.md)
- [fSenseLengthRequested](scsiperipheralsdriverkit/scsideviceoutparameters/fsenselengthrequested.md)
- [fDataBufferAddr](scsiperipheralsdriverkit/scsideviceoutparameters/fdatabufferaddr.md)
- [fSenseBufferAddr](scsiperipheralsdriverkit/scsideviceoutparameters/fsensebufferaddr.md)