Hi Raymond,
For dedicated DASD, CP doesn't look at the SHARED setting (or really
anything else); the CCW goes straight to the hardware.
For Minidisks,
- If the "v" suffix is not defined on the MDISK statement in the user
directory, a command reject is simulated; I assumed this was the case
specified in the original note.
- If the "v" suffix is defined and the minidisk is a fullpack (0-END) *and*
SHARED is defined in SYSTEM CONFIG, then the CCW goes to the hardware.
- If the "v" suffix is defined and the minidisk is not a fullpack *or*
SHARED is not defined, then the CCW is completely simulated and no I/O goes
to the hardware.
Steve Wilkins
IBM VM Development
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|Raymond Noal <[EMAIL PROTECTED]>
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|IBMVM@LISTSERV.UARK.EDU
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|09/26/2008 05:34 PM
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|Re: Reserve/Release
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Steve,
I’m a little confused by your reply for R/R processing.
For minidisks, the MDISK statement in the directory allows you to specify
access modes with MWV where the ‘V’ stands for CP’s simulation of virtual
R/R processing. In this case, for a minidisk, I always thought that CP
would simulate the R/R processing but CP would also change the R/R CCW to a
SENSE CCW. Moreover, if the real DASD where the minidisk is allocated is
defined to CP as SHARED, CP was obligate to send the R/R CCW to the
hardware.
For dedicated DASD to a virtual machine, if the dedicated device is defined
to CP as SHARED, the CP will pass the R/R CCW to the hardware. If the
dedicated DASD is not defined as SHARED, CP will change the R/R CCW to a
NOP or SENSE CCW, I can’t remember which.
I can’t think of any configuration combination where CP would treat a R/R
CCW as a command reject.
OK, I know it’s Friday and I may be having a really bad ‘senior moment’
here, so I would appreciate any clarification you have for this topic.
TIA
HITACHI
DATA SYSTEMS
Raymond E. Noal
Senior Technical Engineer
Office: (408) 970 - 7978
From: The IBM z/VM Operating System [mailto:[EMAIL PROTECTED] On
Behalf Of Steve Wilkins
Sent: Friday, September 26, 2008 8:52 AM
To: IBMVM@LISTSERV.UARK.EDU
Subject: Re: Reserve/Release
For minidisks (fullpack included): It will be rejected (Command Reject)
For dedicated: It hits the iron (i.e., goes to the hardware).
Steve Wilkins
IBM VM Development
