Hi Folks,
I hope this post isn't considered a waste of everyone's time. I
came across this "design element" (so to speak) in my work concerning
the Broadcast Dataset (aka SYS1.BRODCAST, in its more restrictive sense).
Question: When you are reformatting the active Broadcast Dataset
(SYS1.BRODCAST) with the SYNC command, you create space for 100 global
Notices (the messages that everybody sees when they LOGON). How do you
change this number?
Answer: You probably would never want to change this number,
because 100 notices is adequate for most purposes. But what if you
really DO want to change this number? Then IBM tells you to zap a
fullword field at the beginning of TSO initiation module IKJEFXSR, and
re-IPL (maybe with CLPA, just to be safe). Again, you'd probably never
want to do this, because 100 notices is adequate for almost everyone.
Where is that number (100, or F'64') kept? It is actually a
fullword in the CVT itself, at displacement X'5A8'. It is not "chained
off the CVT". It is actually a fullword IN the CVT...!!!! Wow!
So how would a fullword in the CVT be changed? Presumably only at
IPL time. That's why IBM's method of changing it is so cumbersome,
since (I think) IKJEFXSR, which starts up TSO, has to put that number
into the CVT.
Anyway, if someone REALLY wants to change this number (temporarily,
for the duration of the IPL), I wrote an authorized TSO command called
BDMNNOTC, which will take a number as a parameter, convert it to
fullword binary, and zap it into CVT + X'5A8'. This command is on CBT
File 731 (www.cbttape.org). It works instantly. So you say: BDMNNOTC
50, or BDMNNOTC 150, and if you do a SYNC afterwards, that number of
NOTICES records will be formatted into the (active) Broadcast Dataset.
If you are really doing this, please see the notes in the program
source, on CBT File 731.
I submitted a request to IBM quite a few years ago, that maybe an
entry should be put into PARMLIB member IKJTSOxx, with the format
NUMNOTICES(nnn), which would change this number whenever you do a
PARMLIB UPDATE(xx) TSO command or a SET IKJTSO=xx console command.
Since this requirement probably has the lowest priority that could ever
be assigned to an enhancement request, I'd guess that it probably would
never get done. But meanwhile, the sysprog community has my BDMNNOTC
solution, if they want it.
I guess I've taken enough of your time. Hope it's food for some
thinking--and maybe it'll eventually lead to some productive progress
somewhere.
Thanks for listening. All the best of everything to all of you.
Sincerely, Sam
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