First, I would suggest reading the man pages and similar articles
that are in InfoExplorer on "alog". It is used to log the out of
some commands to a subsystem file specified within "alog".
In this case, it is used to log boot information, so if you have a
problem, you can look at the alog file to try and determine the problem.
In this case, it is not the "alog" command that is the problem, if
this is like any problems I have encountered in the past.
If this is IBM software that you installed and is causing this, then
I am MIGHTY surprised. This indicates that this software has
modified your /etc/rc file, which is really a NO-NO.
Any customized software should have its OWN startup script and have
it's own entry in /etc/inittab.
What I suspect is that entries in the /etc/rc script that have been
added are SUPPOSED to act like daemons, but they have neglected to
completely detach themselves from there parent process, etc.
If they still have any file descriptors for things like STDIO, then
when the parent completes it execution, these descriptors are kind of
passed up the chain to complete any outstanding I/O. In this case, since
the /etc/rc file has its output piped to another command, it in
essense causes the pipe to hang. Until ALL the file descriptors that
have output connections to this pipe close, then the other side of
the pipe remains open and no further progress is ever made.
With a little bit of work you can reproduce this this same situation
without "alog" OR /etc/rc.
> Hello all ---
> My 42T with AIX 4.1.4 usually runs fine. But after I installed
> IBM's "Visualization Data Explorer", the machine doesn't boot
> properly. After executing /etc/rc, the machine just stopped
> the boot process.
> In maintanace mode, I found the something with (or close to)the
> inittab must be going wrong. After some tests I tried to remove
> the "alog" command from the lines of inittab listed below, and everything
> went fine.
> Annother machine, a 530H, is running the unchanged inittab without
> any trouble.
> Because my man's aren't set up yet, I didn't understand what's going
> on. If anybody knows, what 'alog -tboot' and 'fbcheck' are doing in
> this context, please let me know.
> Thank You
> Gerald Masan
> Some lines of my inittab.
> -This did'nt work:
> rc:2:wait:/etc/rc 2>&1 | alog -tboot > /dev/console # Multi-User checks
> fbcheck:2:wait:/usr/sbin/fbcheck 2>&1 | alog -tboot > /dev/console # run
> - But these did:
> rc:2:wait:/etc/rc 2>&1 > /dev/console # Multi-User checks
> fbcheck:2:wait:/usr/sbin/fbcheck 2>&1 > /dev/console # run /etc/firstboot