The problem is that the operating system does not know how to mount a VTAPE. In 
the MVS world, there was what was known as a DCB Exit that could be activated 
at EOV and EOF. It could be taught to determine the type of tape and either do 
a VTMOUNT (VTAPE) or VMTAPE MOUNT (real tape) at EOV. But that is customer, not 
vendor, code. I do not know if the same is true in VSE (or even z/OS, for that 
matter). 

I have to agree about the black hole. I have gotten replies to neither mail, 
dumps nor phone calls since the first of May.  I wish Rick Bourgeois well and 
hope that the staff soon learns how to support the products half as well as he 
did. This has probably been a tough time for them, but they do need to step up 
and carry the load.



Regards, 
Richard Schuh 

 

> -----Original Message-----
> From: The IBM z/VM Operating System 
> [mailto:[email protected]] On Behalf Of Hughes, Jim
> Sent: Wednesday, June 17, 2009 7:22 PM
> To: [email protected]
> Subject: Re: Trace I/O for a 3490 tape drive
> 
> When IDCAMS is run in VSE with a real 3490 tape drive and it 
> reaches EOT, it asks for another tape.  Run the same job 
> again and when either the Library Mdisk assigned to the 
> virtual tape volume runs out of space or the SIZE limit 
> assigned to the virtual tape volume is reached, I'd expect 
> IDCAMS to ask for another tape volume. Instead the IDCAMS job 
> aborts with Intervention required.
>  
> Same program and different results at EOT.
>  
> I wish the VTAPE support people would talk to us a little 
> more. They are a black hole at this point.  We could really 
> use VTAPE in our environment too.
>  
> _____________________
> Jim Hughes
> x5586
> "It is fun to do the impossible." Quote from Walt Disney
> 
> ________________________________
> 
> From: The IBM z/VM Operating System on behalf of Schuh, Richard
> Sent: Wed 6/17/2009 4:08 PM
> To: [email protected]
> Subject: Re: Trace I/O for a 3490 tape drive
> 
> 
> 
> You will probably find that you must write exit routines to 
> run in your guest. I do not know the capabilities of VSE 
> along those lines, but the MVS line, at least at one time, 
> supported all sorts of different DCB exit routines. At a 
> former job, we had exit routines that wee used in 
> applications where it was critical that they be allowed to 
> continue using another tape. These routines checked to see if 
> the tape was real or VTAPE, and either issued a VTMOUNT 
> (VTAPE) or a VMTAPE MOUNT.
> 
> I think that you will find that the VSSI product is true to 
> the device being simulated. It is probable that the s/w that 
> interfaces with the device is unaware of VTAPE and tries to 
> get a real tape mounted at EOT. It is not that the device is 
> presenting something different to the O/S (not to IDCAMS), it 
> is that the O/S is unaware that VTAPE is involved.
> 
> The usual EOT indication is, if my memories are current with 
> today's tape hardware, to present a Unit Exception in the 
> status. What happens beyond that is purely the business of 
> the operating system and access method.
> 
> Regards,
> Richard Schuh
> 
> 
> 
> > -----Original Message-----
> > From: The IBM z/VM Operating System
> > [mailto:[email protected]] On Behalf Of Hughes, Jim
> > Sent: Wednesday, June 17, 2009 12:29 PM
> > To: [email protected]
> > Subject: Re: Trace I/O for a 3490 tape drive
> >
> > Here is the problem.
> >
> > We are evaluating VTAPE from VSSI. Our VSE machines get 
> Intervention 
> > Required when EOT is sensed when running an IDCAMS backup.
> >
> > I am want to organize a trace to a real 3490 tape drive so 
> I can see 
> > the behavior when a real 3490 presents EOT to IDCAMS.
> >
> > Then I want to do the same thing using a Virtual tape drive and 
> > compare the tape commands and interrupts.
> >
> > If we cannot get beyond this problem with VTAPE, we won't 
> be able to 
> > buy the product.  The vendor isn't offering much in the way 
> of support 
> > so I'm trying to get ahead of the game and give the vendor as much 
> > information about the nature of the problem as possible.
> >
> > If you are telling me that I won't see any interrupts or commands 
> > using TRSOUCE except for a few xSCH commands, then I am on a fool's 
> > errand.
> >
> > Since you know what I am trying to do, perhaps you can recommend a 
> > better method.
> >
> > Suggestions welcomed.
> >
> > ____________________
> > Jim Hughes
> > 603-271-5586
> > "It is fun to do the impossible."
> >
> > ==>-----Original Message-----
> > ==>From: The IBM z/VM Operating System 
> > [mailto:[email protected]] On ==>Behalf Of Alan Altmark
> > ==>Sent: Wednesday, June 17, 2009 2:25 PM
> > ==>To: [email protected]
> > ==>Subject: Re: Trace I/O for a 3490 tape drive ==> ==>On 
> Wednesday, 
> > 06/17/2009 at 12:58 EDT, "Hughes, Jim"
> > ==><[email protected]> wrote:
> > ==>> I?d like to trace all i/o, interrupts, etc for a 3490 
> tape drive.
> > ==>...
> > ==>> My trace command is:
> > ==>> CP TRACE IO 181 CCW INS  INT BOTH  RUN ==>> ==>> I?ve used 
> > various other combinations of TRACE SIO and TRACE SSSCH and ==>etc?
> > ==>> with no happiness.
> > ==>>
> > ==>> I can get the TSCH and SSCH commands to appear and 
> nothing else.
> > ==>>
> > ==>> What can I do to get ALL the tape i/o for address 181 
> to show up?
> > ==>
> > ==>What other I/O were you expecting?  If the guest is in a 
> TSCH loop, 
> > it ==>typically won't get I/O interrupts.  They will be 
> drained by the 
> > TSCH.
> > ==>
> > ==>Alan Altmark
> > ==>z/VM Development
> > ==>IBM Endicott
> > 
> 

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