Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!apple!agate!shelby!siegman@sierra
From: siegman@sierra.STANFORD.EDU (siegman)
Newsgroups: comp.sys.mac.apps
Subject: Re: How the System Installer Works (Important)
Keywords: Installer
Message-ID: <87@sierra.STANFORD.EDU>
Date: 17 Jan 91 02:17:31 GMT
References: <85@sierra.STANFORD.EDU> <1991Jan16.235950.16515@parc.xerox.com>
Distribution: comp.sys.mac.apps
Organization: Stanford University
Lines: 52

In article <1991Jan16.235950.16515@parc.xerox.com> Rex Sanders writes:

(referring to the Installer's default property of really only
updating, not repairing or fully replacing, system resources)

>This is NOT the wrong way to do things.  By using the Installer you can
>update your System from version x to y WITHOUT having to dance with the
>Font/DA mover, or re-installing your Ethernet driver.  With the present
>
>Now, if your System is *damaged*, then what should happen?  Trash your
>Fonts, DAs, and other unusual widgets?  How do you distinguish between
>a "good" resource, "bad" resource, and "modified-by-user-for-good-reason"
>resource?
>

Reasonable arguments (and as I said, I'm NOT an expert on this).  But:

1) Installer could SAY what it's doing; it could print a log
("Replaced MUNG resource with updated value"), so you'd know what it
had, and had not, done.

2) It could ASK YOU what you wanted it to do ("Trash existing system?"
Or perhaps, "Replace ALL resources?  Or only UPDATED resources?").  It
could ask you, "Retain all existing DAs and fonts?".

3) I'd still argue that: 

(a) Repairing (often unknown) system damage (from a crash, sudden
power failure, magnitude 6.5 earthquake :-)) is a MUCH more common
task than merely updating a system, or installing a new system.
Hence, that would be a more useful thing for the Installer to do as
its default action.

(b) And, since the Installer is, in fact, used to install a NEW system
(when a new system comes out, or a new machine is purchased), I think
it's a much more reasonable or obvious assumption for the novice user
to make that running the Installer again will install a NEW system
again.

(c) Making this assumption does imply that added DAs and fonts will be
lost.  But a well-known tool, Font/DA Mover, exists for handling this;
handling the problem of saving fonts and DAs is fairly obvious for
even nonspecialists.  How many ordinary users mess with the system
file beyond that?  Very few, I would think.  If INITs or other more
sophisticated programs change the system file (something I don't
know), that will be handled by the restart required after installation
anyway, won't it?

It still seems to me that a complete rebuild would be the preferred
default action for the Installer.

--AES