Question on Read Buffer command

Pat LaVarre p.lavarre at
Mon Oct 11 08:33:24 PDT 2004

* From the T10 Reflector (t10 at, posted by:
* Pat LaVarre <p.lavarre at>
> SPC-3 for the letter ballot.  In clause 6.15.6 Read Data from echo 
> buffer (0Ah), the draft standard reads, "If a prior echo buffer mode 
> WRITE BUFFER command was not successfully completed, the echo buffer 
> mode READ BUFFER command shall terminate with CHECK CONDITION status, 
> with the sense key set to ILLEGAL REQUEST, and the additional sense 
> code set to COMMAND SEQUENCE ERROR."  If a WRITE BUFFER command was 
> never sent by an initiator, then no prior command was successfully 
> completed, resulting (as you wrote) in a COMMAND SEQUENCE ERROR.

Sad to see us become more of an industry, less of a craft.

I remember firmware for which this test case was an easter egg, i.e., 
when you're working down at the level where you can provoke the 
silliness of asking to read before writing, then you reliably get back 
a personal message of congratulations for your conscientious attention 
to detail from the design team, e.g., their initials.

Pat LaVarre

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