Reference Guide

Chapter 4 SCSI Commands
READ ATTRIBUTE Command (8Ch)
DLT-S4 Interface Reference Guide 260
LOAD/UNLOAD AT PARTITION:
Indicates whether the media can be
loaded or unloaded at the partition specified by the Partition Number
field in the CDB.
Support for Host Vendor-Unique Attributes 4
Tape drives allocate a fixed size (1,029 bytes) for the host to write its host
vendor-unique EMAM attributes. These attributes can be numbered in
the range 1400h through 17FFh. Since attribute headers are 5 bytes in
length, if the host wants to write one attribute, there are 1,024 bytes of
attribute data space available. If the host wants to write two attributes—
one maximum and one minimum—the largest the maximum can be is
1,029 (total) – 5 (max. attribute header) – 5 (min. attribute header) – 1
(min. attribute data) or 1,018 data bytes, and the smallest the minimum
can be is 1 byte.
Host vendor-unique attributes can be added and deleted. A write to a
host vendor-unique attribute causes the drive to test the size remaining
(Attribute ID 4:MAM Space Remaining) and if the write does not cause an
out-of-memory condition, the drive allows it. An application is allowed to
write an attribute marked as read only to the host vendor-unique area,
but this attribute can never be deleted.
Unique Features of the
DLT-S4 Tape Drive
Implementation of Read /
Write Attributes 4
Keep these features and considerations in mind:
• Super DLTtape media does not support the non-existent state for
attributes.
• All attributes that exist are reported in the attribute list and attribute
values.
• The tape drive does not support deleting standard host type
attributes (
WRITE ATTRIBUTE commands with attribute length of 0).
The only attributes that can be deleted are host vendor-unique
attributes.
• Super DLTtape media only supports ASCII text in the
TEXT
LOCALIZATION IDENTIFIER
attribute.
Note: The format of the host vendor-unique attributes contents are
up to the host to determine.