Gilles Schipper wrote:

> From my experience, it is okay to issue the devctrl command against a tape
> drive that is either loaded or not loaded - as long as it is not "IN THE
> PROCESS" of entering either state.

:showdev dat
 LDEV     AVAIL         OWNERSHIP         VOLID         DEN   ASSOCIATION

    7     AVAIL    (W)                    L03149(ANSI)  1600
    8     AVAIL    (W)                    L02506(ANSI)  1600
   11     AVAIL
   12     AVAIL    (W)                    L06227(ANSI)  1600
   22     UNAVAIL  (W)  #J887: 1 FILES    L01685(ANSI)  1600
:devctrl.mpexl.telesup 22 compression=enable
Device = 22, Compression=enable, Eject=Nochange, Load=Nochange

Unable to establish device ownership
Subsys:          231
Error :          -36

END OF PROGRAM

(22 definitely has a tape loaded...but i doubt this is what gilles meant :-)  i
suspect that a test of the device's availability is the real indicator....

> Also, since one can never be sure that an intervening compression-enabling
> or disabling devctrl command has occurred, it is probably wise to include
> the appropriate devctrl command in the job stream ahead of the tape output
> command that requires compression or absence thereof.

true

> Unfortunately, this may not be that straight-forward, since the invocation
> of the devctrl command normally requires non-standard capabilities.

<sigh>  do i feel a rant coming on....?
<rant> (i guess i do) we've asked hp before to please do something about
devtool (the program that devctrl is actually running) and (more or less) the
answer was 'no'.  we've got a tool that (imo) is broken.  ok, so yes it works
in a rudimentary fashion but is it fit for the real world?  no.  *any* system
level program should *at least* set hpcierr if it encounters a problem!  does
devtool?  no.  does it do anything about setting a variable or even a jcw?
no.  can it actually create a problem?  yes (given my 30+ hour backup).  does
it handle dlt's correctly?  no (try doing a devctrl...compression=enable on a
dlt with *no* cartridge mounted (it hangs)).
</rant>

i'll call hp tomorrow and see what sort of progress i can make.  if i'm lucky,
i'll get an sr opened....like that will do any good....            - d

--
Donna Garverick     Sr. System Programmer
925-210-6631        [log in to unmask]

"Unix _is_ user friendly.
It's just very selective about who its friends are.
And sometimes even best friends have fights."

>>>MY opinions, not Longs Drug Stores'<<<