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Inside Macintosh: Devices /

Chapter 4 - SCSI Manager 4.3 / SCSI Manager 4.3 Reference

Data Structures

Command Descriptor Block Record

You use the command descriptor block record to pass SCSI commands to the SCSIAction function. The SCSI commands can be stored within this structure, or you can provide a pointer to them. You set the scsiCDBIsPointer flag in the SCSI parameter block if this record contains a pointer.

The command descriptor block record is defined by the CDB data type.

union CDB
{
   UInt8    *cdbPtr;
   UInt8    cdbBytes[maxCDBLength];
};
typedef union CDB CDB, *CDBPtr;

Field Description

cdbPtr

A pointer to a buffer containing a CDB.

cdbBytes

A buffer in which you can place a CDB.