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Chapter 7 |
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Extended Unit Options (18H) | Page 7 - 49 |
TAG - The function of this bit varies depending on whether the adapter is in
Initiator or Target Mode.
Initiator Mode
Tagged Commands - In initiator Mode, one of the design options offered with the
0 ⇒ Tagged commands not negotiated.
1 ⇒ Peripheral supports tagged commands - negotiate for it.
Target Mode
Selection of Group 2 Commands - During Target Mode operations, the Tag bit controls whether Group 2 6- or
0 ⇒
1 ⇒
Sense Count
The RF3880 adapter automatically responds to a device Check Condition with a SCSI Request Sense command. (Unless inhibited on a per command basis with the IRS bit of the
The Request Sense command, issued by the adapter to the device with the Check Condition, can garner Sense information of up to 256 bytes. The number returned depends on the number asked for in the SCSI Request Sense command that is issued by the adapter. The Sense Count field is used to define the number of Sense bytes the adapter will ask for when automatically issuing a Request Sense command.
Valid values for this field are 0 to 32 (20H).
If more than 32 bytes of sequential sense information is requested, the count will be set to 8 and error code A1H will be returned.
Otherwise, the value you place in the Sense Count field is used in conjunction with the Selected Sense Bytes Fields. There are three ways you can use the Sense Count and Selected Sense Bytes fields to get the result you want:
To receive the default
•Place a zero value in Sense Count field.
•Place zeroes in all fields of Selected Sense Bytes.
To receive any sixteen bytes of Request Sense Data from the possible 256:
•Place a zero in the Sense Count field.
•Place the Sense Byte number in each of the sixteen fields of the Selected Sense Bytes, in the order desired.
User’s Guide | 21020285 D |