Path: utzoo!utgpu!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!husc6!rice!sun-spots-request
From: auspex!guy@uunet.uu.net (Guy Harris)
Newsgroups: comp.sys.sun
Subject: Re: And then he moved /boot to /usr...
Message-ID: <668@auspex.UUCP>
Date: 19 Dec 88 23:16:39 GMT
References: <3445@geaclib.UUCP>
Sender: usenet@rice.edu
Organization: Sun-Spots
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Approved: Sun-Spots@rice.edu
Original-Date: 10 Dec 88 05:52:41 GMT
X-Sun-Spots-Digest: Volume 7, Issue 62, message 2 of 12

>Does anyone know if the physical position of /boot on the disk is
>critical?  I'm wondering if the roms find boot at a fixed offset...

The ROMS do not find "/boot" at all; they find the boot block, and do not
know anything about the filesystem organization.

Prior to SunOS 4.0, the boot block knew enough about the way the 4.2BSD
file system worked that they could find the blocks of "/boot".  The 4.0
version (and possibly the Sys4-3.2 version) has had a lobotomy, so it no
longer knows much at all about the way the 4.2BSD file system works (I
think this was done because the program was getting too big to fit in the
boot block, at least on a SPARC machine); there is a program "installboot"
(see INSTALLBOOT(8S)) that, when used to install a new version of "/boot",
jams the physical addresses of the blocks of "/boot" into a table in the
boot block.