SCSI Primary Commands - 2.pdf

18 July 2001 T10/1236-D Revision 20Reads and writes shall be performed using whole-block transfer lengths determined by the block size, transferlength, or both. Therefore some source data may remain unprocessed and some destination data may not havebeen transferred at the end of a segment. If so, the residue shall be handled according to the CAT bit in thesegment descriptor and the PAD bits of the source and destination target descriptors, as defined in table 30.SourcetargetdescriptoraPAD bit inDestinationtargetdescriptorCAT bitTable 30 — PAD and CAT bit definitionsCopy manager action0 or 1 0 or 1 1 Any residual source data shall be retained as source data for a subsequentsegment descriptor. Any residual destination data shall beretained as destination data for a subsequent segment descriptor. Itshall not be an error if either the source or destination target index in thefollowing segment descriptor does not match the corresponding targetindex with which residual data was originally associated. If the CAT bit isone on the last segment of an EXTENDED COPY command anyresidual data shall be discarded; this shall not be considered an error.1 1 0 Any residual source data shall be discarded. Any residual destinationdata shall be padded with zeroes to make a whole block transfer. a0 1 0 Any residual source data shall be handled as if the CAT bit is equal toone (i.e., discarded on the last segment and retained otherwise). Anyresidual destination data shall be padded with zeroes to make a wholeblock transfer. a1 0 0 Any residual source or destination data shall be discarded.0 0 0 If there is residual source or destination data the EXTENDED COPYcommand shall be terminated with a CHECK CONDITION status. Thesense key shall be set to an COPY ABORTED and the additional sensecode shall be set to UNEXPECTED INEXACT SEGMENT.When the CAT bit is set to zero and the destination target descriptor has the PAD bit set to one, theEXTENDED COPY command shall be terminated with a CHECK CONDITION status, the sense key shall beset to COPY ABORTED, and the additional sense code shall be set to UNEXPECTED INEXACT SEGMENTif any of the following conditions are met:a) If any residual destination data is present after writing the designated byte range for a segmentdescriptor of type 09h (stream→block ) or 0Ah (block→block); orb) If any residual destination data is present after the designated number of blocks have been written for asegment descriptor of type 02h (block→block) with DC set to one, 0Dh (block→block+application client)with DC set to one, 01h (stream→block) or 0Ch (stream→block+application client).A few segment descriptors have either no source or no target and handling of the PAD bit for those descriptors shallbe as follows. For segment descriptor types 04h (inline→stream, see 7.2.7.7) and 05h (embedded→stream, see7.2.7.8), the handling shall be as if the PAD were equal to zero for the source target descriptor. For segmentdescriptor types 06h and 0Fh (stream→discard and stream→discard+application client, see 7.2.7.9), handlingshall be as if the PAD were equal to zero for the destination target descriptor.dpANS SCSI Primary Commands - 2 (SPC-2) 61