Bruce Toback wrote:
>
> Michael Anderson writes:
> [snip]

> >
> >However in POSIX I can:
> >
> >---------------------
> >> mv SBR0000 SBR0000O
> >> mv SBR0000N SBR0000
> >>---------------------
> >
> >I kinda like the idea of bypassing the need to log users off the system to do
> >this, but then I make some people around here (TIW) nervous.
>
> One other difference between these two is that the :RENAME command
> updates the file's access and modify times. The POSIX mv command does
> not. So in this case, you won't be able to look at the file's modify
> timestamp to see when it was moved into place.
>

My take on this is, the filename can change a 1000 times, but if the contents
of the file and/or the disc address haven't changed why change the modify
timestamp?

OTOH, the access timestamp should be updated, another POSIX command falling
just short of the mark.

Also the "mv" command in POSIX doesn't care if you are the CREATOR of the
file, As long as file permissions (ACD's) are setup a particular way, or you
have "SM" capability.

Having a good and thorough idea of what exactly a command does is important
to me before using it. Somehow it's always after using a command that it's
true strengths and weaknesses are revealed :-)

I'm thinking maybe that using POSIX commands to get around MPE rules maybe
the first step to losing the MISSION CRITICAL ATTITUDE  that MPE has always
had. I am sure that MPE's rules have a purpose and should NOT be
side-stepped. However it's nice, after you have analyzed all the factors
involved (make sure you know when you don't know) and decided that you really
need to side-step an MPE rule, that in some cases POSIX will allow it.

Cheers,

Michael "If it isn't broke, break it!" Anderson,

Systems Programmer
TIW Corporation