Path: utzoo!mnetor!uunet!husc6!bloom-beacon!tut.cis.ohio-state.edu!im4u!ut-sally!utah-cs!utah-gr!stride!stride1!mitch
From: mitch@stride1.UUCP (Thomas P. Mitchell)
Newsgroups: comp.sources.d
Subject: Re: Wiping out /bin in OS upgrades
Message-ID: <756@stride.Stride.COM>
Date: 29 Mar 88 17:24:59 GMT
References: <1682@desint.UUCP> <1007@mcgill-vision.UUCP> <46626@sun.uucp> <1703@desint.UUCP>
Sender: news@Stride.COM
Reply-To: mitch@stride1.Stride.COM (Thomas P. Mitchell)
Organization: MicroSage Comp. Sys. Inc., 680 S. Rock Blvd, Reno, NV 89502
Lines: 60
Summary: Start with a Clean Slate

In previous articles <1703@desint.UUCP> geoff@desint.UUCP (Geoff Kuenning)
<46626@sun.uucp> chuq@sun.UUCP (Chuq Von Rospach) write:
About updates that destroy this file and that dir.

>>> that it destroyed, but among them: /etc/rc (almost, barely, just
>
>> As someone who seems to upgrade weekly (someone has to run the stuff before
>> customers do.... I find Sun upgrades to be relatively painless, as long as
>> you're careful about what you do to the standard system directories. I'm

>... Too bad Sun doesn't see fit to document Chuq's
>personal habits as a "you must do it this way" procedures.

Not in defense of Sun, or us here at MicroSage and other Unix(TM)
vendors let me comment.

A Unix release like our UniStride or Sun's is large.  Perhaps
huge is a better word.  Ours is some 5000+ files (cpio -ot | wc).
Maintaining a coherent product of this size IS a monumental task.
Updates to anything of this size are also a non trivial task.

The only way I have found to update a customer cleanly is to have
that customer:
	1) Backup his system (some have none)
	2) Backup his users areas
	3) Isolate local changes and additions. ***
		a) /etc/passwd; b) /etc/group etc.
	4) Install the release from scratch on new file systems.
		a) mkfs on all devices
		b) run all configuration scripts and programs
	5) Install file by file each of the local changes.
	6) Install the user areas.
	7) Respond to any missing items by extracting from the backup.

Time after time I have chased down a 'bug' report that resulted
from a half way update.  Sometimes it is only a manual page that
no longer matches the program,  other times it is an include
file.  Because Unix was designed to get multiple use from program
code the interactions are many in number.

One real problem is 'dead' programs.  With time files left
behind from previous releases can begin to eat up disk space.
Worse when invoked they call other programs now changed only
slightly.

*** 

Local changes.  System managers very much need to keep a system
notebook. ("Nut Shell" people???)  I am constantly amazed by
customers who never keep records about the hardware they have, let
alone the installed software.  After all what is a manager!

P.S.  My thanks to Chuq Von Rospach for the shell script I saved
a copy.


Thomas P. Mitchell (mitch@stride1.Stride.COM)
Phone: (702)322-6868	TWX: 910-395-6073	FAX: (702)322-7975
MicroSage Computer Systems Inc. a Division of Stride Micro.
Opinions expressed are probably mine.