WIN2000 & FreeBSD

Adam blueeskimo at
Sun Jun 29 13:36:40 PDT 2003

On Sun, 2003-06-29 at 16:12, Jerry McAllister wrote:
> Here there seems to be some confusion on the use of the word partition.
> FreeBSD uses the term "slice" to mean the major division of the disk
> that Microsloth uses the term "partition" for.   You need only two of
> these slices (MS partitions) - one for Windows and one for FreeBSD
> although you can have as many as 4.   Those slices are identified in
> FreeBSD land as s1..s4 (ad0s1..ad0s4 for IDE disk one for example) and
> as a letter drive in the MS netherworld (typically drive c, d, etc)
> These major divisions called slices are created by fdisk.
> Then, you further divide the FreeBSD slice in to partitions using disklabel
> which are named a..h.    FreeBSD calls these sub divisions 'partitions'.
> You create filesystems on these FreeBSD partitions and mount them.  
> There are conventions and expectations for some of these.  Usually 'a' is
> used for the root (/) file system, 'b' is used for swap, 'c' us unused
> and set up to refer to the whole slice by a few things, 'd' seems to be 
> unused, but I don't know the reason.  The remainder (e-h) have any use
> although often 'e' is used for /tmp 'f' is often used for /usr or /var
> or sometimes /home depending on how you choose to spread out and manage
> your disk space.  
> Often second and and subsequent extra disks are assigned to one whole
> use and in that case it is common to use either 'a' or 'e' or 'f' to
> be its name.  Some times a chunk of each extra disk is used to add to
> swap space and typically the name 'b' is used for each of those regardless
> of which other letter names are used for the rest of the disk.
> So, for example, if you have a machine with 3 IDE disks, split the first
> to be boot disks for MSwin and FreeBSD, dedicate the second to MSwin and
> use the third to add to swap and work space, you might have disks addressed
> as follows:   (Size choices are up to you, but remember, you always want more)
>              ad0s2a  mounted as /    (eg root)
>              ad0s2b  swap
>              ad0s2c  a comment describing the whole ad0s2 slice
>              ad0s2e  mounted as /tmp
>              ad0s2f  mounted as /usr
>              ad0s2g  mounted as /var
>              ad0s2h  mounted as /home
>              ad2s1b  swap
>              ad2s1f  mounted as /work
>              ad1s1   cal also be msdos mounted as something if you like.
> Note:  You will need to install the boot loader on each disk that will have
> bootable systems on it.    In this example, that is only ad0.   And you will 
> need to put a Master Boot Record on the first boot disk (from the BIOS point
> of view) - ad0 in this example.  If you choose to make all of the first
> disk (ad0) be dedicated to MSwin and the second disk (ad1) dedicated to
> FreeBSD, for example, you would need to write a boot loader on both ad0 
> and ad1 and the FreeBSD MBR on the first disk (ad0) even though you don't
> put any other FreeBSD stuff on that disk.  That is because the BIOS starts
> with that first disk to figure out how to boot and then the MBR takes over
> from there.   And, at least up to WinXP the Microsloth MBRs could not boot
> a UNIX OS - but FreeBSD could do either.   I have heard tell that now the
> MBR that comes with XP can do both, but haven't tried it.
> Although the descriptions of fdisk and disklabel in the man pages can
> at first be rather confusing, after a while they begin to make sense and
> are relatively easy to use.    
> But, you can also use the sysinstall, either from an install CD or
> by invoking /stand/sysinstall and it will also do all your calculations
> for you in a minimal GUI interface.   Sysinstall will also make it write
> the boot loader and MBR if you want.
> MS doesn't have anything exactly the same as those sub-partition divisions 
> of the slice (tho it does have something else vaguely similar called an 
> extended partition that is not compatible).
> So, this was a bigger comment than I had planned, but we seem to go over
> and over this same confusion so often.

Thanks Jerry! This is one of the most informative posts I have seen in a
long time. All newbies should read this post very closely!

Adam <blueeskimo at>

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