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- Newsgroups: comp.sys.mac.system
- Path: sparky!uunet!europa.asd.contel.com!howland.reston.ans.net!wupost!micro-heart-of-gold.mit.edu!uw-beaver!uw-coco!nwnexus!phaedrus
- From: phaedrus@halcyon.com (Mark Phaedrus)
- Subject: Re: Duo's: Are Redundant Systems A Good Idea?
- Message-ID: <1992Dec13.184407.16748@nwnexus.WA.COM>
- Sender: sso@nwnexus.WA.COM (System Security Officer)
- Organization: The 23:00 News and Mail Service
- References: <562@blue.cis.pitt.edu>
- Distribution: na
- Date: Sun, 13 Dec 1992 18:44:07 GMT
- Lines: 36
-
- In article <562@blue.cis.pitt.edu> nick+@pitt.edu (Nick C De Mello) writes:
- > Good news! I've finally got my Duo 230!
- > Bad news! I don't have a mini dock or disk drive yet!
- > As you can imagine, I'm *really* paranoid about crashing my system
- >under these circumstances. I have an idea in case I do, but am
- >not sure if it is safe. Let me know what you think of the following.
- > My day to day system is in folder A, a backup system is in folder B.
- >I put A on my hard disk, I put B,in a folder, in a folder, on my hard
- >disk. When I start up the first system found is A, and if A is ok, the
- >Duo never looks for B. If A gets trashed, the Duo looks lower in the
- >hierachy until if finds B, it boots, and I can repair A and restart.
-
- Bad idea. When you create a System Folder on a Macintosh disk, a little
- Macintosh icon should appear on that folder in the Finder. That Mac icon means
- that that folder has become the "blessed folder". Even if you have multiple
- System Folders on the disk, only one will be the blessed folder; only one
- will have that Mac icon. At startup time, when the Mac is looking for a System
- Folder to boot from, it doesn't rummage all over the disk looking for one.
- It goes to the blessed folder and uses the System there. If that System Folder
- is corrupted for some reason, the Mac doesn't care whether there are any other
- System Folders on that disk or not; it goes and looks for another disk to boot
- from instead.
- So, if you create multiple System Folders on your Duo's disk, you're
- doing nothing to improve reliability in the event of System Folder corruption
- (if your "blessed" System Folder dies, the fact that your other System Folder
- is perfectly fine won't matter in the slightest), and you're introducing
- reliability problems into your system (the system may decide to move the
- "blessing" from one System Folder to another at any time, which can cause
- software to become extremely confused). You're probably _increasing_, not
- decreasing, the risk of corrupting your Duo to the point that it no longer
- boots.
- --
- \o\ Internet: phaedrus@halcyon.com (Seattle, WA Public Access Unix) \o\
- \o\ "How'd you like to move a few steps down the food chain, pal?" \o\
- \o\ If you enjoy fantasy/SF stories with transformation themes, email me \o\
- \o\ for a copy of the Transformation Stories List. \o\
-