SCSI Primary Commands - 2.pdf

T10/1236-D Revision 20 18 July 2001While a prevention of medium removal condition is in effect, the target shall inhibit mechanisms that normally allowremoval of the medium by an operator.7.13 READ BUFFER command7.13.1 READ BUFFER command introductionThe READ BUFFER command (see table 79) is used in conjunction with the WRITE BUFFER command as adiagnostic function for testing memory in the SCSI device and the integrity of the service delivery subsystem. Thiscommand shall not alter the medium.Table 79 — READ BUFFER commandBitByte7 6 5 4 3 2 1 00 OPERATION CODE (3Ch)1 Reserved MODE2 BUFFER ID3 (MSB)4BUFFER OFFSET5 (LSB)6 (MSB)7ALLOCATION LENGTH8 (LSB)9 CONTROLThe function of this command and the meaning of fields within the CDB depend on the contents of the MODE field.The MODE field is defined in table 80.7.13.2 Combined header and data mode (0000b)Table 80 — READ BUFFER MODE fieldMODE DescriptionImplementationrequirements0000b Combined header and data Optional0001b Vendor specific Vendor specific0010b Data Optional0011b Descriptor Optional0100b - 1001b Reserved Reserved1010b Echo buffer Optional1011b Echo buffer descriptor Optional1100b - 1111b Reserved ReservedIn this mode, a four-byte header followed by data bytes is returned to the application client in the Data-In Buffer.The BUFFER ID and the BUFFER OFFSET fields are reserved.114 dpANS SCSI Primary Commands - 2 (SPC-2)