Keywords - Seagate Ultra160 Product Manual

SCSI Interface Product Manual, Rev. B 9
task management request—A request submitted by an application client, invoking a task management func-
tion to be executed by a task manager.
task management response—The response returned to an application client by a task manager on comple-
tion of a task management request.
task manager—A server within the target which executes task management functions.
task set—A group of tasks within a SCSI target port device, whose interaction is dependent on the queuing
and auto contingent allegiance rules of Section 7.6.1.
task slot—Resources within the logical unit that may be used to contain a task.
task tags—A Tag is a field containing up to 64 bits that is a component of a Tagged Task Identifier. A SCSI ini-
tiator port assigns tag values in each Tagged Task Identifier in a way that ensures that the identifier uniqueness
requirements stated in ANSI SAM-2, T10/1157D, Section 4.9, are met.
third-party command—A SCSI command which requires a logical unit within the target device to assume the
initiator role and send a SCSI command to a SCSI target port device.
transaction—A cooperative interaction between two objects, involving the exchange of information or the exe-
cution of some service by one object on behalf of the other.
transfer period—The negotiated time between edges of REQ or ACK that latch data. For ST, the transfer
period is measured from assertion edge of the REQ or ACK signal to the next assertion edge of the signal. For
DT, the transfer period is measured from a transition edge of the REQ or ACK signal to the next transition edge
of the signal.
unconfirmed protocol service—A service available at the protocol service interface, which does not result in
a completion confirmation.
unlinked command—A SCSI command having the link bit set to zero in the CDB control byte.
upper level protocol—An application-specific protocol executed through services provided by a lower level
protocol.
1.2.2

Keywords

Several keywords are used to differentiate between different levels of requirements and optionality, as follows:
vendor-specific—Specification of the referenced item is determined by the device vendor.
protocol-specific—Implementation of the referenced item is defined by a SCSI protocol standard (see Sec-
tion 1.1.1.)
expected—A keyword used to describe the behavior of the models specified by this standard.
invalid—A keyword used to describe an illegal or unsupported bit, byte, word, field, or code value. Receipt of
an invalid bit, byte, word, field, or code value shall be reported as an error.
mandatory—A keyword indicating items required to be implemented as defined by this standard.
may—A keyword that indicates flexibility of choice with no implied preference (equivalent to "may or may not").
may not—Keywords that indicates flexibility of choice with no implied preference (equivalent to "may or may
not").
obsolete—A keyword indicating items that were defined in prior SCSI standards but have been removed from
this standard.
option, optional—Keywords that describe features which are not required to be implemented by this standard.
However, if any optional feature defined by the standard is implemented, it shall be implemented as defined by
the standard.
reserved—A key word referring to bits, bytes, words, fields, and code values that are set aside for future stan-
dardization. Their use and interpretation may be specified by future extensions to this or other standards. A
reserved bit, byte, word, or field shall be set to zero, or in accordance with a future extension to this standard.
Recipients are not required to check reserved bits, bytes, words, or fields for zero values. Receipt of reserved
code values in defined fields shall be treated as an error.