Date: Wed, 02 Sep 1998 19:43:37 -0600 From: Brett Glass <brett@lariat.org> To: Scott Blachowicz <sab@seanet.com>, Scott Blachowicz <sab@seanet.com>, Dan Nelson <dnelson@emsphone.com> Cc: Doug White <dwhite@resnet.uoregon.edu>, questions@FreeBSD.ORG Subject: Re: MSDOS extended partitions and "slices" Message-ID: <199809030146.TAA03143@lariat.lariat.org> In-Reply-To: <19980902183643.A5424@dniquote.com> References: <199809030043.SAA02590@lariat.lariat.org> <199809022113.PAA00535@lariat.lariat.org> <199808080608.AAA16222@lariat.lariat.org> <199808021131.FAA12204@lariat.lariat.org> <199808080608.AAA16222@lariat.lariat.org> <199809021901.MAA21131@two.sabami.seaslug.org> <199809022113.PAA00535@lariat.lariat.org> <19980902175652.A11500@emsphone.com> <199809030005.SAA02250@lariat.lariat.org> <19980902172833.A3976@dniquote.com> <199809030043.SAA02590@lariat.lariat.org>
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At 06:36 PM 9/2/98 -0700, Scott Blachowicz wrote: >On Wed, Sep 02, 1998 at 06:41:52PM -0600, Brett Glass wrote: >> The latter is actually more flexible, as it accounts for any scheme in >> which one of the four possible "slices" (to use the FreeBSD parlance) is >> then subdivided. (IBM's standard allows for no more than four.) > >But, so does the current scheme (or what am I missing here?). Anything that >corresponds to a DOS drive gets a slice number. Yes, but this is misleading, because a DOS drive isn't always a slice! It's often a smaller section within a slice. That's why it's called a "logical" DOS drive. >I meant flexible in that >you could partition up your FreeBSD slice without having to worry about >fdisk/DOS re-partitioning. But if you call the logical drive /dev/wd0s2a, >it's harder to subdivide into BSD partitions (I suppose you could call the >partitions /dev/wd0s2aa, wd0s2ab, etc but that looks weird). FreeBSD would be in a different slice. >> What's more, it reflects the hierarchy better; there's no guessing about >> the device name of "the second logical DOS drive in the extended DOS >> partition." With the scheme that's being used now, you have to know what >> other partitions contain before you can figure out the name. > >I thought the current scheme would always have the 2nd logical DOS drive in >the extended DOS partition as /dev/wd0s6. Slices 1 thru 4 are defined as >the primary partition slices, slice 5 is the first logical, slice 6 is the >second logical, etc... Not necessarily. What if there's no primary slice 4? (Answer: everything rolls down a number.) >On the other hand...if it's possible to have a DOS partition get turned >into an extended partition, then I see the point...for instance, if you >start off with > > slice 1 - normal partition > slice 2 - normal partition > slice 3 - Extended partition > slice 5 - 1st logical drive > slice 6 - 2nd logical drive > slice 4 - empty > >then you turn slice 2 into an extended partition keeping slice 3 as an >extended partition, then you have trouble because you can't predict the slice >numbers that get assigned to the logical drive inside slice 3. That's right. This is one of the problems. The names should reflect the hierarchical structure, and the names of the logical drives should NOT be affected by what's in the other slices. >Is the >number of logical drives in an extended partition limited to 4 as well? Nope. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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