Date: Tue, 21 Nov 2000 12:23:26 -0800 From: Cy Schubert - ITSD Open Systems Group <Cy.Schubert@uumail.gov.bc.ca> To: stable@FreeBSD.ORG Subject: Re: Removal of Disklabel Message-ID: <200011212023.eALKNwF25397@cwsys.cwsent.com> In-Reply-To: Your message of "21 Nov 2000 20:23:46 %2B0100." <xzpn1etf7st.fsf@flood.ping.uio.no>
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In message <xzpn1etf7st.fsf@flood.ping.uio.no>, Dag-Erling Smorgrav writes: > FreeBSD <freebsd@KIWI-Computer.com> writes: > > The problem with the fdisk slices is that there is only room for 4 ... > > disklabel gives us 8, no wait.. 6 if you have a swap and 5 if you don't. > > Six (a, d, e, f, g, h) plus swap (b), and there's nothing that says b > has to be a swap partition, so make that seven. There's nothing that > says a swap partition has to be partition b either, BTW. > > Technically, you can use c as well, but that's playing with fire. I'm on tangent mode this afternoon, so this is not a direct reply. The use of various slices, e.g. "c" for the whole disk, is steeped in tradition, when some sites would use a dd(1) command to backup disks to tape or to other disks. Similarly slice "a" was used for the root partition and slice "b" was used for swap, and "g" & "h" were used for /usr and /export -- at least that's the say Sun sets up their systems. The "d" and "e" slices were used to divide the disk in half, if you didn't want to use any of the others. For the newbies out there, read Evi Nemith's UNIX System Administration Handbook. The first edition had a good explanation of this topic with pictures. For you newbies out there, the concept of slices and partitions in the same breath may seem overwhelming, however here is how it works. FreeBSD partitions a disk using the classic PC fdisk partitions (slices in FreeBSD speak), so that a disk may be shared with non-FreeBSD operating systems. Disklabel partitions (partitions in FreeBSD speak) are the native BSD and UNIX way of partitioning a disk. As FreeBSD is only supposed (logically from our point of view) to see the FreeBSD partition and ignore the rest (non-FreeBSD slices for all intents and purposes don't exist when we're running FreeBSD just like FreeBSD slices don't exist when you're running NT), the partitions within a slice mimic the traditional partitions on a disk on other UNIX systems, e.g. Suns. You newbies can consider FreeBSD partitions as Microsoft/IBM extended partitions. The other thing you newbies will notice is the word partition and slice being used interchangeably. BSD documentation uses the word partition to describe a partition in the context of disklabel. Of course IBM and Microsoft also use that word to describe fdisk partitions (slices in FreeBSD speak). To add to the confusion, Sun and AT&T used the word slices to describe their version of disklabel partitions, created by a format(8) command. This confusion of terms even confuses me who has been working on UNIX for quite some time. Just as everything else in UNIX-land is supposed to be standard, every vendor and author of software in this business recycles terms for their use. Here's a Rosetta Stone for all you newbies who may be terribly confused by all this partitions and slices speak. Unit FreeBSD Speak M$/IBM Speak Sun/AT&T ~~~~ ~~~~~~~~~~~~~ ~~~~~~~~~~~~ ~~~~~~~~ fdisk partition slice partition - disklabel partition partition extended partition slice Of course Microsoft used AT&T's term slice to denote a disklabel partition when they marketed Xenix. Hence once again confusion reigns in the IT industry. (Don't even get me started about the telecommunications industry). For you newbies, if you use the above table, hopefully you'll be less confused. Regards, Phone: (250)387-8437 Cy Schubert Fax: (250)387-5766 Team Leader, Sun/DEC Team Internet: Cy.Schubert@osg.gov.bc.ca Open Systems Group, ITSD, ISTA Province of BC To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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