User Manual

SCSI Commands Reference Manual, Rev. J 35
www.seagate.com Definitions, Symbols, Abbreviations, Keywords, And Conventions
1.3 Keywords
Expected
A keyword used to describe the behavior of the hardware or software in the design models assumed by this manual. Other hardware and soft-
ware design models may also be implemented.
Ignored
A keyword used to describe an unused bit, byte, word, field or code value. The contents or value of an ignored bit, byte, word, field or code
value shall not be examined by the receiving SCSI device and may be set to any value by the transmitting SCSI device.
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 an item that is required to be implemented as defined in this manual.
May
A keyword that indicates flexibility of choice with no implied preference (equivalent to “may or may not”).
May not
Keywords that indicate flexibility of choice with no implied preference (equivalent to “may or may not”).
Obsolete
A keyword indicating that an item was defined in prior SCSI standards but has been removed from this manual.
Optional
A keyword that describes features that are not required to be implemented by the standard. However, if any optional feature defined in the
standard is implemented, then it shall be implemented as defined in this manual.
Reserved
A keyword referring to bits, bytes, words, fields and code values that are set aside for future standardization. A reserved bit, byte, word or field
shall be set to zero, or in accordance with a future extension to this manual. 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 reported as an error.
Restricted
A keyword referring to bits, bytes, words, and fields that are set aside for use in other SCSI standards. A restricted bit, byte, word, or field shall be
treated as a reserved bit, byte, word or field for the purposes of the requirements defined in this manual.
Shall
A keyword indicating a mandatory requirement. Designers are required to implement all such mandatory requirements to ensure interopera-
bility with other products that conform to this manual.
Should
A keyword indicating flexibility of choice with a strongly preferred alternative; equivalent to the phrase “it is strongly recommended.”
Vendor-specific
Something (e.g., a bit, field, or code value) that is not defined by this manual and may be used differently in various implementations.