Path: utzoo!utgpu!water!watmath!clyde!rutgers!im4u!ut-sally!utah-cs!utah-gr!uplherc!nrc-ut!nrcvax!kvc
From: kvc@nrcvax.UUCP (Kevin Carosso)
Newsgroups: comp.os.vms
Subject: Re: VWS Weirdness, template devices ?
Keywords: vws, template devices
Message-ID: <1371@nrcvax.UUCP>
Date: 27 Jan 88 02:58:32 GMT
References: <52@tmpmbx.UUCP>
Reply-To: kvc@minnie.UUCP (Kevin Carosso)
Organization: Network Research Corp.  Oxnard, CA
Lines: 48

In article <52@tmpmbx.UUCP> pengo@tmpmbx.UUCP (Hans H. Huebner) writes:

>processes onto each window. To archive this, i need to know the name of the
>created window, since WTA0: is only a template device. I haven't been playing
>around with these template devices so far, but in my understanding i get a
>new pseudodevice if i assign a channel to the template (i.e. a X.29
>terminal with VAX PSI, a new window with VWS, a new pseudo tty with the pty
>driver etc..). It would now at least be logical if DCL remembered the name
>of the created device. Unfortunately the logical name which identifies the
>opened file translates to "_TMPMBX$WTAx", where x is a number which doesn't
>get used for a created terminal. For example, if i have one window on my
>screen (WTA1:), and open WTA0: to create a new window, the logical of the
>opened window translates to _TMPMBX$WTA2:, but WTA2: doesn't exist. The
>*real* name of the new window is WTA3:. This looks at least strange to me.
>Furthermore, if i open a second channel to WTA0:, the logical name again
>translates to _TMPMBX$WTA3, and the device is named WTA4:.

This less-than-desireable behaviour is attributable, I believe, to a
misfeature in RMS.  When you assign a channel to a template device, such
as WTA0:, a new device WTAn: is created, where n is increased by one each
time (and wraps around at 9999).  When you open a device with RMS, it seems
to assign more than one channel to the device.  I'm not sure why, but perhaps
it wants to retrieve device information.  In any case, it does it incorrectly
since it assigns a channel to the device you gave it (e.g. WTA0:), actually
gets a channel to a new device (e.g. WTA3:), does whatever it's gonna do
and stores away the name, then deassigns that channel (which causes
WTA3: to be deleted) and assigns another one to the template (creating
WTA4:).  This is all fine, but for some reason it "remembers" the now-useless
name of the first device -- this is what shows up in your DCL-opened
logical name.

I think the fault lies with RMS and not DCL because I remember having the
same problems trying to do something like "COPY X.DAT WTA0:" which should
create a window on the workstation, throw X.DAT at it, and then delete the
window.  I think that got me a "no such device" error and when you next
create a window you notice that the unit number is 2 greater than before,
implying that the RMS open created not one but two devices -- hence I
arrived at the scenario I described above.

Excuse me if I'm totally offbase here, but it was last summer when I
was fooling around with this and I can't try it out right now.

This is something that should be SPR'ed.

        /Kevin Carosso                     kvc@nrcvax.uucp
         Network Research Co.              kvc%nrcvax@trwind.trw.com
                                           kvc@engvax.scg.hac.com
                                           kvc@ymir.bitnet