Path: utzoo!attcan!uunet!husc6!mailrus!ames!ncar!noao!stsci!morrow
From: morrow@stsci.EDU (Andy Morrow)
Newsgroups: comp.os.vms
Subject: Re: Group Logicals at Startup
Message-ID: <375@stsci>
Date: 12 Jul 88 18:07:07 GMT
References: 
Organization: Space Telescope Science Institute, Baltimore, MD 21218
Lines: 49

From article , by mdeleo@lynx.northeastern.EDU:
> 
>   
>     I was wondering if anyone out there knows who to set-up a group
> logical "automatically" so that it has the following parameters:
> 	[kernal] [shareable,group]
> 	[protection=(RWED,R,R,)] [Owner=[5,0]]
>    		-->>Name::: (LNM$Group_000005)
> 	I can get it to put in everything but the [kernal].
>     Please reply to info-vax or send replys to address below.
> 		
> 		Thanks in advance.
> 		Michael Deleo
> 		 mdeleo@lynx.northeastern.edu
> 		 acm_md@nuhub.northeastern.edu
> 
> Disclaim:  Nothing I say means anything to anyone ...
> 	    Especially Norhteastern Univ. nor my employer Mobil Oil.

> ===========================================================================

In VMS V3.x, I maintained an application that, at system startup, would create
the appropriately named exec mode group table and define its group logicals all
in the system startup command file.  This stopped working with VMS 4.x.   After
booting our VAX a half dozen times one night, I finally realized what happens
in this brave new world.  The first job created that is in a particular group
modifies the system forever by causing the system to create the kernel mode,
noalias group table for that job.  

You can easily demonstrate this to yourself by logging in on an account in one
group and typing $show logical lnm$group_*/table=lnm$system_directory
and then logging in on an account in a group that no jobs have previously
existed for and doing the show again.  The lists will be different and every
subsequent $show will include the new group, for as along as the system is up.

For system startup group logicals, I have found the easiest way to get things
working sensibly is to have the system startup file do a $submit/username=
for an account that is in the desired group and turns on grpnam.

I haven't looked at the fiche to see how to create other kernel mode tables
since I haven't had other problems like this for non-group tables and since
I have a high level solution that works (a changing VMS eventually will 
exact revenge on low level fixes).

Hope this helps.

						andy morrow

morrow@stsci.edu