Date: Sun, 23 Sep 2001 07:45:42 -0500 From: Mike Meyer <mwm@mired.org> To: Wijnand Wiersma <freebsd@4business.nl> Cc: questions@freebsd.org Subject: Re: partitions and slices Message-ID: <15277.55670.807648.190727@guru.mired.org> In-Reply-To: <3687411@toto.iv>
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Wijnand Wiersma <freebsd@4business.nl> types: > a friend of me asked me "why do I have to create slices within a > partition? what's the function of this? what's wrong with partitions > only like linux?" > > I couldn't answer it, who can? The Unix partitioning scheme predates the DOS partitioning scheme, and is quite a bit saner in general, providing 7 general purpose partitions - though I'd like to be told what breaks if C isn't the entire slice on a recent system - vs. 4 slices, with a magic slice type that can hold yet more slices. Preserving the traditional partitions for platforms that don't use DOS slices is obviously a good thing. Since DOS slices are normally used to hold multiple operating systems, the ability to put partitions inside a slice is a good solution for multi-booting OSs. It certainly beats other such compromises I've seen - say ignoring DOS slices and having to make sure the slices & partitions don't overlap by hand - hands down. If you were designing a Unix-like OS from scratch for IBM-PCs - like Linus did - you might use standard DOS slices. Even then, you really need two partitions for an install to get swap. Some have proposed using the Dangerously Dedicated mode - where you treat the entire disk as a slice - to avoid having partitions. While this works, and I do it, the reason it's called Dangerously Dedicated is because there are BIOSes out there that see the BSD boot sector as a virus, and either refuse to boot, or repair it - frying your partition table in the process. That's why it's called "Dangerously". Some systems refuse to boot from sliced disks, which is why DD hasn't gone away. On the other hand, as indicated, other systems refuse to boot in DD mode. Personally, I recommend against using DD unless you have to. The amount of space it saves is negligible, the headache from having your partition table fried is *not* negligible, and should you change your mind about dual booting, it makes the conversion process saner. And no, I'm not saying you might want to boot Windows. I did the conversion to get an SMP BeOS system running at one point. <mike -- Mike Meyer <mwm@mired.org> http://www.mired.org/home/mwm/ Q: How do you make the gods laugh? A: Tell them your plans. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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