David:
Not SFS. We are invoking DITTOVSE from a 3rd-level CMS user,
running under a 2nd-level z/VM, to VSEs running both under the
first-level z/VM and on OTHER VM systems on other CPUs.
DITTOVSE uses IUCV, so any connection must be supported by IUCV.
We have it working with REAL CTCs, but I was questioning if there was
another way.
In theory, I see no reason why TCP couldn't be the medium, but
IUCV doesn't support that type of connection.
David Wakser
-----Original Message-----
From: The IBM z/VM Operating System [mailto:[EMAIL PROTECTED] On
Behalf Of David Boyes
Sent: Wednesday, October 10, 2007 11:10 AM
To: [email protected]
Subject: Re: Defining virtual CTCAs
> Yes, that was what I thought. But I received an answer from someone at
> IBM (regarding a DITTO problem between nodes) that indicated that a
> virtual CTC would work. I believe that person must have been mistaken,
> because I cannot see how! So, I approached the list for verification!
At one point in the past, Princeton University had a tool for extending
CTC connections over IP, written specifically for extending NJE
connections (ie, before RSCS had TCPNJE support). It worked very well
for that purpose. I did a little bit of tinkering with it at a previous
job and got it to support VTAM PU connections, but those mods are long
lost in the holocaust at the end of that employer's VM system, and now
that Princeton is mainframe-free, I suspect the source to that tool is
also lost.
BCTCs are highly lock-step devices (ESCON CTCs are too, just different);
it's easy to stall one in a funny state you can't get out of without a
reset, or have to deal with missing interrupts. If you try to extend
them over a media that doesn't support guaranteed delivery in real time,
it gets *very* interesting.
What are you trying to do with the ISLINK connection? SFS? If so, find a
copy of IPGATE, which will transport APPC over IP. We use it heavily for
sharing SFS pools between VM systems. Remote PERFKIT sessions appear to
work as well (if you actually understand enough about APPC to configure
the COMDIR entries correctly).
