Date: Sun, 16 Aug 1998 05:56:13 +1000 From: Bruce Evans <bde@zeta.org.au> To: jdp@polstra.com, julian@whistle.com Cc: current@FreeBSD.ORG Subject: Re: Funky DEVFS stuff. Message-ID: <199808151956.FAA24483@godzilla.zeta.org.au>
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>> The 'c' partition is "Magic" (for now) > >Is 'd' still magic too? I seem to recall that it was magic once upon >a time. But not any more, right? No. At least not in FreeBSD (versions >= 2.0.5). 'c' isn't as magic as it used to be. It mainly has conventional uses that might cause problems for programs and users that blindly believe that the convensions are followed. E.g., the bootblocks default to 'a' and may give stray results unless you specify 'c'. If 'c' isn't the only partition with a nonzero size, then you don't want to use it for anything (except disk labeling and bad144 data) since it overlaps the other partitions. You don't really want to use it for labelling or bad144 data either. Normally the 'a' partition overlaps the label, and if 'a' is used for an ffs filesystem or swap then the label won't be overwritten. Foreign newfs's (run on 'a') will probably attempt to overwrite the label and fail because the label is write protected. >Also, 'b' used to be magic (reserved for swap) in some Unix variants. >Not for us, right? It is conventionally reserved for swap in FreeBSD too. It is a bit more than conventionally reserved for kernel dumps in FreeBSD - dumps are not permitted on devices whose minor is 1 modulo 8 (see kern_shutdown.c:dumpsys() and autoconf.c:setdumpdev()). Bruce To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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