8.0 where the details of each command are described.
[3]The Logical Block Address on logical units or within a partition on device volumes shall begin with block zero and be contiguous up to the last logical block on that logical unit or within that partition.
A
[4]The Transfer Length specifies the amount of data to be transferred, usually the number of blocks. For sev- eral commands the transfer length indicates the requested number of bytes to be sent as defined in the command description. For these commands the transfer length field may be identified by a different name. See the following descriptions and the individual command descriptions for further information.
Commands that use one byte for Transfer Length allow up to 256 blocks of data to be transferred by one command. A Transfer Length value of 1 to 255 indicates the number of blocks that shall be transferred. A value of zero indicates 256 blocks.
Commands that use two bytes for Transfer Length allow up to 65,535 blocks of data to be transferred by one command. In this case, a Transfer Length of zero indicates that no data transfer shall take place. A value of 1 to 65,535 indicates the number of blocks that shall be transferred.
For several commands more than two bytes are allocated for Transfer Length. Refer to the specific com- mand description for further information.
The Transfer Length of the commands that are used to send a list of parameters to a drive is called the Parameter List Length. The Parameter List Length specifies the number of bytes sent during the DATA OUT phase.
The Transfer Length of the commands used to return sense data (e.g., REQUEST SENSE, INQUIRY, MODE SENSE, etc.) to a SCSI initiator port is called the Allocation Length. The Allocation Length speci- fies the number of bytes that the initiator has allocated for returned data. The drive shall terminate the DATA IN phase when Allocation Length bytes have been transferred or when all available data have been transferred to the initiator, whichever is less.
[5]The Parameter List Length field is used to specify the number of bytes sent from the
[6]The Allocation Length field specifies the maximum number of bytes that an application client has allocated for returned data. An allocation length of zero indicates that no data shall be transferred. This condition shall not be considered as an error. The device server shall terminate transfers to the
[7]Only the Control fields have consistently defined meanings across all commands. The Control field is the last byte of every command descriptor block, except for the variable length CDB format. The Control field is defined in Table 62.
136 | Parallel SCSI Interface Product Manual, Rev. A |
