Fujitsu M2488, Руководство по эксплуатации продукта

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MEDIA CHANGER COMMANDS M2488 PRODUCT GUIDE
6-12 CG00000-011503 REV. A March 1997
2
6-7 The Page Control (PC) field indicates the type of page parameter values to be
returned by the target. The target returns the same page length for each supported
page regardless of the value in the PC. The combination of the page control field
value and the page code being set causes the target to return the appropriate values
for the page selected by its respective page code. A Page Code value of 3Fh indi-
cates all pages implemented by the target are returned to the initiator with the values
reported defined by the page control field. For a Page Code value of 3Fh, all pages
are returned in ascending page code order, except for mode page 00h, which will
always be reported last. The PC field is defined in Table 6-10.
Regardless of the setting of the PC field, the Mode Sense data header will return the
current values for the fields contained in it, since the SP (Save Pages) bit only
applies to the Mode Pages, and not the header.
4 The Allocation Length specifies the number of bytes the initiator has allocated for
returned MODE SENSE data. An Allocation Length of zero indicates no MODE
SENSE data is to be transferred. This condition is not considered as an error. Any
other value indicates the maximum number of bytes transferred. The target termi-
nates the DATA IN phase when allocation length bytes have been transferred or
when all available MODE SENSE data has been transferred to the initiator, which-
ever is less.
Table 6-10. PC Field
PC FIELD
BITS
DESCRIPTION
7 6
0 0
Report Current Values: The current values are those parameters under which the target is presently config-
ured. The current values are defined to be the following:
1. those values set in the last successfully completed MODE SELECT command
2. saved values if a MODE SELECT hasn’t successfully completed since the last power-on, hard reset
condition or BUS DEVICE RESET message,
3. default values if saved values are not available.
Page fields not supported are set to zero. The additional page length field returned by the target indicates
the number of bytes supported in that page.
0 1
Report Changeable Values: The changeable values of any page indicate which parameters the initiator
may change by a subsequent MODE SELECT command. Any field allowed to change is set to all ones.
Fields and bits not allowed to be changed by the initiator are set to zero. Attempting to change any field,
via MODE SELECT command, that is not changeable causes the target to return a CHECK CONDITION
status with the sense key set to ILLEGAL REQUEST in the sense data. The additional page length field of
each page returned by the target indicates the number of bytes which are supported for that particular
page.
1 0
Report Default Values: The target returns to the initiator the field values set to the target’s or device’s
default values. The additional pages length field of each page returned by the target indicates the number
of bytes supported for that particular page.
1 1
Report Saved Values: The target returns the saved values of the mode parameters. Until the first success-
ful MODE SELECT command is completed with the SP (Save Pages) bit set to 1, the default values will
be returned for this PC field setting.
Table 6-9. MODE SENSE Field Description (Continued)
BYTE BIT VALUE DESCRIPTION