SCSI Primary Commands - 2.pdf

18 July 2001 T10/1236-D Revision 207.19 REPORT LUNS commandThe REPORT LUNS command (see table 99) requests that the peripheral device logical unit inventory be sent tothe application client. The logical unit inventory is a list that shall include the logical unit numbers of all logical unitshaving a PERIPHERAL QUALIFIER value of 000b (see 7.3.2). Logical unit numbers for logical units with PERIPHERALQUALIFIER values of 100b, 101b, 110b, or 111b may optionally be included in the logical unit inventory. A SCSIdevice that is capable of supporting a LUN address other than zero shall support a REPORT LUNS command thatis addressed to logical unit zero. Support of the REPORT LUNS command by logical units other than logical unitzero is optional. Support of the REPORT LUNS command on devices having only a single logical unit with thelogical unit number of zero is optional.Table 99 — REPORT LUNS commandBitByte7 6 5 4 3 2 1 00 OPERATION CODE (A0h)1 Reserved2 Reserved3 Reserved4 Reserved5 Reserved6 (MSB)78ALLOCATION LENGTH9 (LSB)10 Reserved11 CONTROLThe allocation length should be at least 16 bytes. If the allocation length is not sufficient to contain the entire logicalunit inventory, the device server shall report as many logical unit number values as fit in the specified allocationlength. This shall not be considered an error.NOTE 27 Devices compliant with SPC return CHECK CONDITION status with sense key ILLEGAL REQUEST andadditional sense code set to INVALID FIELD IN CDB when the allocation length is less than 16 bytes.The REPORT LUNS command shall return CHECK CONDITION status only when the device server is unable toreturn the requested report of the logical unit inventory.If a REPORT LUNS command is received from an initiator with a pending unit attention condition (i.e., before thedevice server reports CHECK CONDITION status), the device server shall perform the REPORT LUNS command.If the unit attention condition was established because of a change in the logical unit inventory, that unit attentioncondition shall be cleared for that initiator by the REPORT LUNS command. Unit attention conditions establishedfor other reasons shall not be cleared by the REPORT LUNS command (see SAM-2).The REPORT LUNS data should be returned even though the device server is not ready for other commands. Tominimize delays after a hard reset or power-up condition, the default report of the logical unit inventory should beavailable without incurring any media access delays. The default report of the logical unit inventory shall contain atleast LUN 0.dpANS SCSI Primary Commands - 2 (SPC-2) 133