[comp.sources.d] OS upgrades

jwp@chem.ucsd.edu (John Pierce) (03/30/88)

Yeah, this is an annoying subject....  But I have some sympathy for vendors,
too.  Mostly they've got to design this sort of thing for people who have no
idea whatever about what they're doing.  We finally decided to put in the
effort to write scripts that save everything we really care about someplace
where it's easy for us to get it back.  Life's been a lot simpler since then.
Sure, the vendor's going to change it on you.  Just put back the old binaries
(it's very unlikely they won't run) and recompile as you get the chance.

It only requires a little thought, and the occassional screw up, to make this
relatively less painful than griping about what the vendor did to you.  They
don't have a chance in hell of figuring out everything you may have changed.

-- 
	John Pierce			Chemistry Dept, B-032, UC San Diego
	Internet:  jwp@chem.ucsd.edu	UC San Diego, La Jolla, CA  92093
	Bitnet:    jwpierce@ucsd	+1 619 534 0203

rsalz@bbn.com (Rich Salz) (03/31/88)

When a release is sent out, the vendor should include a file that lists
the stat(2) information and a checksum of every file.  The first part of
upgrading a new release is to compare this file with the current state of
the system.  That way, if the checksum of /etc/rc.local is not what was
originally shipped, you can at least warn the sysadmin.  I wrote such a
program once, and the company used it all the time.  It's not hard, even
when you're selective (e.g., "do a stat of everything in
/rel1.2/xy/include except /rel1.2/xy/include/sys, and assume the
destination is /xy/include").  In fact, I recall that the UniSoft port
of SystemV had something like this.

One tricky part is proper updating of the file for maintenance releases.

It's almost always a mistake to blindly wipe out entire directories,
rather than inserting new files.  And requiring people to repartition
their disks shows a real lack of foresight on the vendor's part.

I remember being real pleasantly surprised by how nicely most upgrades
from mt. Xinu and Pyramid were handled.

This is an interesting discussion, but it's not really about sources;
where should it go?
	/r$
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