Date: Thu, 6 May 1999 18:34:33 -0400 (EDT) From: Zhihui Zhang <zzhang@cs.binghamton.edu> To: Mike Smith <mike@smith.net.au> Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: Boot blocks Questions (was: superblocks in FFS) Message-ID: <Pine.GSO.3.96.990506182729.16113E-100000@sol.cs.binghamton.edu> In-Reply-To: <199905062232.PAA01917@dingo.cdrom.com>
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> > > > 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. > Let me put my understanding in your words: (1) The gap is BBSIZE bytes or 16 sectors. (2) This gap does not belong to cylinder group 0 and the size of cylinder group 0 is BBSIZE less than other cylinder groups. But if you say this gap belongs to cylinder group 0 (the block bitmap will not include them of course), then all cylinder groups are of the same size (the last cylinder group may of a different size). -Zhihui To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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