TAPE UNIT SCSI COMMANDS M2488 PRODUCT GUIDE
4-110 CG00000-011503 REV. A April 1997
12-15 The Capacity field is intended to be used to determine that the correct density is
being used, particularly when a lower-density format is required for interchange.
The meaning of the Capacity field is dependent on the setting of the Media bit in
the CDB:
a) When the Media bit in the CDB is 0, the capacity field indicates the approxi-
mate capacity of the longest supported medium for this density. For density 09h
(18-track) the approx. capacity is 240MB (F0h). For density 28h (36-track) the
approx. capacity is 800MB (320H) (i.e. approx. capacity of the extended length
tape, which is the longest supported medium for this density).
b) When the Media bit in the CDB is 1, the capacity field indicates the approxi-
mate capacity of the currently mounted medium for this density. For density 09h
the approx. capacity is 240MB (F0h). For density 28h, the capacity is dependent
on the tape length (standard or extended) of the currently mounted medium. For
standard length tapes, the approx. capacity is 400MB (190h). For extended
length tapes, the approx. capacity is 800MB (320h).
Notes:
a) The capacity is based on compression being disabled.
b) The capacity is based on the media being in “good” condition and that “nor-
mal” data and block sizes are used.
c) The logical unit does not guarantee that this space is actually available in all
cases.
d) Direct comparison of this value between different vendors (possibly prod-
ucts) is discouraged since the length of media and the method used to mea-
sure maximum capacity may vary.
16-23 The Assigning Organization field contains eight bytes of ASCII data identifying
the organization responsible for the information in this DENSITY SUPPORT
data block. The data is left aligned within this field. The ASCII value for a space
(20h) is used if padding is required.
24-31 The Density Name field contains eight bytes of ASCII data identifying the name
that is associated with this DENSITY SUPPORT data block. The data is left
aligned within this field.
32-51 The Description field contains 20 bytes of ASCII data describing the density.
The data is left aligned within this field. The ASCII value for a space (20h) is
used if padding is required.
Table 4-104. REPORT DENSITY SUPPORT Data Block Field Description (Continued)
BYTE BIT VALUE DESCRIPTION