User's Guide

26 SCSI Commands
Page Code – The Page Code field identifies which log page is being requested by the initiator.
Parameter Pointer - This field specifies which log parameter to begin with for the requested log page. A
PPC bit of 0 and a Parameter Pointer field of 0 will cause all available log parameters for the requested page
code to be returned, subject to the Allocation Length. More detailed definition of this field is contained within
the specific log page descriptions.
Allocation Length - The Allocation Length field is used to determine the maximum amount of data to return.
The transfer completes after either all the data has been transferred or an amount equal to the Allocation
Length has been sent. Specify FFFFh to include all available data.
Log Sense Response
The response to a LOG SENSE command returns the log page specified in the Page Code field of the CDB.
The log page format is described in “Log Page Format.” The valid Page Code fields are listed in Table 21
on page 26. The various log parameters are described within their respective pages, along with their
Parameter Codes. The Log Parameter format is described in “Log Parameter Format.”
Log Page Format
The following table shows the Log Page format. The first four bytes are the Parameter List Header, followed
by the list of log parameters.
Page Code – This field identifies which log page is being transferred.
Page Length - This field indicates the total number of bytes available to return for this page, beginning with
the first log parameter. The value set for this field depends on the value specified for the Page Code.
Log Parameters – These are dependent upon the log page. The various parameters as well as their format
for the supported pages are listed below.
Table 21 Page Code field
Page Code Page Name Page Description
00h Supported Log Pages Returns list of supported log pages
2Eh Tape Alert Log Returns the 64 tape alert flags
Table 22 Log Page format
Bit
Byte
76543210
0 Reserved Page Code
1 Reserved
2
Page Length (n-3)
3
4
:
x+3
Log Parameter (First)
(Length x)
:
n-y+1
:
n
Log Parameter (Last)
(Length y)