IMHO, that's a bass-ackwards solution.

If they only handle 5 CCWs, then they should issue, at worst, a Command 
Reject for anything else.  Good Grief!

If they refuse, find out what they accept, and then give them a list of 
the other 251 hex codes to ignore.  You'd think they could count that 
high?

Mike Walter 
Hewitt Associates 
Any opinions expressed herein are mine alone and do not necessarily 
represent the opinions or policies of Hewitt Associates.



"Schuh, Richard" <[EMAIL PROTECTED]> 

Sent by: "The IBM z/VM Operating System" <[email protected]>
06/26/2008 12:35 PM
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"The IBM z/VM Operating System" <[email protected]>



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Subject
Tape Unit Documentation






We have a vendor that produces a device that responds to the IPL roll call 
saying it is a 3480-04; however, it only uses a subset of the tape unit's 
CCWs. If these devices receive a CCW that is not in their list of 5 that 
they use, bad things, such as streamed unsolicited interrupts or Command 
Rejects, happen. A detach of one of the devices results in the streamed 
unsolicited interrupts which in turn causes the device to be Boxed. Other 
commands like the forward or backward space commands or Read Backward 
cause a Unit Check/Command Reject to be reflected to the guest. I would 
like to be able to provide them with a complete list of commands for which 
they should not cause irreparable harm to the guest. Where can I find 
documentation showing the complete list of CCWs used by real 3480 and 3490 
devices? 
Regards,
Richard Schuh 





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