Date: Thu, 06 May 1999 15:32:06 -0700 From: Mike Smith <mike@smith.net.au> To: Zhihui Zhang <zzhang@cs.binghamton.edu> Cc: Mike Smith <mike@smith.net.au>, freebsd-hackers@FreeBSD.ORG Subject: Re: Boot blocks Questions (was: superblocks in FFS) Message-ID: <199905062232.PAA01917@dingo.cdrom.com> In-Reply-To: Your message of "Thu, 06 May 1999 18:16:39 EDT." <Pine.GSO.3.96.990506181143.16113C-100000@sol.cs.binghamton.edu>
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> > On Thu, 6 May 1999, Mike Smith wrote: > > > > > > > I have some questions regarding the new boot blocks used in FreeBSD 3.1: > > > > > > (1) Can these boot blocks (I assume that they can occupy at most 15 > > > sectors because we need one sector for the disklabel in the first 16 > > > sectors. BBSIZE == 8192) reside in a filesystem other than the root file > > > system? > > > > They don't reside in the root filesystem, they reside at the beginning > > of the slice. > > > > Thanks for the fastest reply I have ever got! For this above point, the > beginning of a FreeBSD slice should belong to the cylinder group 0 of the > first filesystem in the slice, although this filesystem may not be the > root filesystem. Am I right? Not entirely. In order to simplify offset calculations, there's a large gap at the beginning of the filesystem. If the filesystem starts at the very bottom of the slice, this gap will contain the disklabel and bootblocks. If the filesystem is elsewhere, it's just empty. So the beginning of the slice doesn't belong to any CG at all. But you're correct that the first filesystem in a slice may not be the 'a' filesystem, and it may also not be a root filesystem. -- \\ Sometimes you're ahead, \\ Mike Smith \\ sometimes you're behind. \\ mike@smith.net.au \\ The race is long, and in the \\ msmith@freebsd.org \\ end it's only with yourself. \\ msmith@cdrom.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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