【国外标准】 Information Technology - SCSI Block Commands - 4 (SBC-4)

This standard defines the command set extensions to facilitate operation of SCSI direct access block devices. The clauses in this standard, implemented in conjunction with the applicable clauses of SPC-6, specify the standard command set for SCSI direct access block devices. The objectives of this standard are to: a) permit an application client to communicate over a SCSI service delivery subsystem (see SAM-6) with a logical unit that declares itself to be a direct access block device in the PERIPHERAL DEVICE TYPE field of the standard INQUIRY data (see SPC-6); and b) define commands and parameters unique to the direct access block device type. This standard makes obsolete the following concepts from SBC-3: a) the EER bit and DCR bit (see 6.5.10); b) the TMC field and ETC bit in various log parameters; c) the READ LONG command and WRITE LONG command except for write uncorrectable; and d) the XOR command.