Type 3 protection

George Penokie gop at us.ibm.com
Mon Nov 27 06:49:06 PST 2006


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Gary,
The rules for checking are in the footnotes. For example in table 71 
footnote j describes the rules for checking the Reference Tag:
If type 1 protection is enabled, the device server checks the logical 
block reference tag by comparing it to the lower 4 bytes of the LBA 
associated with the logical block. If type 2 protection or type 3 
protection is enabled, the device server checks the logical block 
reference tag if it has knowledge of the contents of the LOGICAL BLOCK 
REFERENCE TAG field. If type 2 protection is enabled, then this knowledge 
may be acquired through the EXPECTED INITIAL LOGICAL BLOCK REFERENCE TAG 
field in a WRITE (32) command (see 5.29). If type 3 protection is enabled, 
then the method for acquiring this knowledge is not defined by this 
standard.
That footnote is telling you that for type 3 protection the target only 
check the reference tag if the target knows what the content is be some 
means not defined by the standard. 
Also, sending out a message on this reflector that states the information 
is "confidential information of Emulex Corporation" is a not a good way to 
get responses. In the future any such messages received on my machine will 
automatically be deleted.
Bye for now,
George Penokie
Dept 9A8 030-3 A410
E-Mail:    gop at us.ibm.com
Internal:  553-5208
External: 507-253-5208
Gary.Franco at Emulex.Com 
Sent by: owner-t10 at t10.org
11/25/2006 07:17 AM
To
<t10 at t10.org>
cc
Subject
Type 3 protection
I would like a clarification on the correct implementation for Type 3 
checking when dealing with WRPROTECT/RDPROTECT/VRPROTECT .
In SBC-3r07 clause 4.17.2.5 Type 3 protection states:
Type 3 protection:
a)	defines the content of the LOGICAL BLOCK GUARD field within the 
logical blocks of the data-in buffer and/or data-out buffer;
b)	does not define the content of the LOGICAL BLOCK APPLICATION TAG 
field; and
c)	does not define the content of the LOGICAL BLOCK REFERENCE TAG 
field.
However in the individual command descriptors, WRITE(10) for example, 
Table 71 ? WRPROTECT field indicates that both the Application Tag and 
Reference Tag should be checked.
Since both of these DIF items are not defined for Type 3 protection, I 
assume that for Type 3 protected devices these fields should not be 
checked at all.
Can someone clarify?
Thanks in advance
__________________________________
Gary Franco Consultant Engineer
Emulex Network Systems
972-671-7433 Dallas Office
972-671-7435 Dallas Office Fax 
720-652-6387 Longmont Colorado Office
720-494-1817 Longmont Colorado Office Fax
972-839-5694 Cell Phone
Today's Quote 
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Thank you. 



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