reconfiguration, please

[Vernon Schryver]

In normal circumstances, you will not notice the kernel in /unix.install.
There should never be a kernel in /usr/sysgen/master.d, unless someone
has been doing some manual experimenting.


The "reconfigure operating system?" question is generated by lboot
when run with the -t arg, by /etc/rc2.d/S95autoconfig.

As described in the lboot(1M) man page, lboot looks around to decide if
a new kernel needs to be built.  It does this by:

    1. probe for devices using the VECTOR lines in /usr/sysgen/system,
	and using the rest of /usr/sysgen/system and the files in
	/usr/sysgen/master.d, generate a new Equiped Device Table,
	in /usr/sysgen/edt.list.new.  If this edt.list.new differs
	from the existing /usr/sysgen/edt.list, skip to step 3 below.

    2. using stat(2), see if any of /usr/sysgen/{system,master.d/*,boot/*}
	are newer than /unix.  If none are newer, then quit.

    3. Ask the "reconfigure" question.  If the operator does not
	responds "yes", then quit. 

    4. generate a new kernel in /unix.install.  This includes generating
	and compiling /etc/sysgen/master.d/master.c, and then linking
	the kernel with ld.

    5. display a message reminding the operator to reboot to use the
	new kernel.  Rename /usr/sysgen/edt.list.new as edt.list.

Please consider where this procedure can go wrong.  The most common
problem is that the "reconfigure" question is asked every time the
system is rebooted.  This is most commonly caused by one of two
problems.  First, someone has changed hardware (see step #1) or
changed software (see step #2).  Aternatively, the dates on the files
in step #2 are bogus, because the system had a crazy idea of the time
when software was installed.

The solution to both of these problems is:
	A.  touch /usr/sysgen/system /usr/sysgen/*/*
	B.  /etc/init.d/autoconfig
	C.  (answer "yes")
	D.  reboot

Please consider the utility of the following to diagnose other "reconfigure
question" problems:
	I.   run /etc/init.d/autoconfig
	II.  instead of answering the question, type control-Z
	III. diff /usr/sysgen/master.d/edt.list*
	IV.  fg; control-C


Vernon Schryver,   Silicon Graphics,  vjs at sgi.com