User Manual

SCSI Commands Reference Manual, Rev. J 480
www.seagate.com Parameters for direct access devices
5.4.6 Block Limits Extension VPD page (B7h)
The Block Limits Extension VPD page (see table 452) provides the application client with the means to obtain certain operating parameters of
the logical unit.
PERIPHERAL QUALIFIER and PERIPHERAL DEVICE TYPE fields
The PERIPHERAL QUALIFIER field and PERIPHERAL DEVICE TYPE field are defined in SPC-5.
PAGE CODE field and PAGE LENGTH field
The PAGE CODE field and PAGE LENGTH field are defined in SPC-5 and shall be set to the values shown in table 452 for the Block Limits Exten-
sion VPD page.
MAXIMUM NUMBER OF STREAMS field
The MAXIMUM NUMBER OF STREAMS field indicates the maximum number of streams that the device server supports and the maximum value
for the stream identifier plus one. A maximum number of streams field set to 0000h indicates that the device server does not support Stream
Control.
OPTIMAL STREAM WRITE SIZE field
The OPTIMAL STREAM WRITE SIZE field indicates the alignment and size of the optimal stream write as a number of logical blocks. The optimal
stream write size is the same for all streams in the device server.
STREAM GRANULARITY SIZE field
The STREAM GRANULARITY SIZE field indicates the stream granularity size in number of optimal stream write size blocks as described in 3.50.
Table 452 Block Limits Extension VPD page
Bit
Byte
7 6 5 4 3 2 1 0
0 PERIPHERAL QUALIFIER PERIPHERAL DEVICE TYPE
1 PAGE CODE (B7h)
2 (MSB)
PAGE LENGTH (n-4)
3 (LSB)
4
Reserved
5
6 (MSB)
MAXIMUM NUMBER OF STREAMS
7 (LSB)
8 (MSB)
OPTIMAL STREAM WRITE SIZE
9 (LSB)
10 (MSB)
STREAM GRANULARITY SIZE. . .
13 (LSB)
14
Reserved. . .
n