How does FreeBSD access NetBSD, OpenBSD?

[Jerry McAllister]

> 
>      On Fri, 28 Jan 2005 11:18:55 -0500 (EST) Jerry McAllister
> <jerrymc at clunix.cl.msu.edu> wrote:
> >> 
> >> I have FreeBSD, OpenBSD, and NetBSD on the same hard drive of my system.
> >> How can I mount the NetBSD or OpenBSD partitions from FreeBSD?
> >> 
> >> Slice 1 - Ext3fs for data between linux/bsd
> >> Slice 2 - OpenBSD slice with 4 ufs partitions and swap (a,b,e,f,g)
> >> Slice 3 - FreeBSD slice with 4 ufs partitions and swap (a,b,d,e,f)
> >> Slice 4 - Extended slice composed of:
> >>    Slice 5 - NetBSD slice with 4 ufs partitions and swap (a,b,e,f,g)
> >>    Slice 6 - Unformatted as of yet.
> >
> >Hmmm,  First thing I see is that only 4 slices are allowed on a drive.
> 
>      Not true.  In fact, I have 8 slices on one of my drives.  The slice
> entries in the Master Boot Record, wherein they are known as "primary
> partition" entries, are four in number, but one of those four can point,
> instead of to a "partition" (i.e., "slice" in UNIX terms), to a chain of
> "logical partition" table entries, known collectively as the "extended
> partition".  The FreeBSD kernel appears to have no trouble with this at
> all.

Well, somebody else has already posted a better answer than mine.
So, problem solved.

But, geez, I would hate to deal with all that much complication on 
one disk.   Extra disks are too cheap to get in to it that deep.

////jerry


>      The main limitation w.r.t. FreeBSD is that the slice containing the
> bootable root file system must be a "primary" rather than a "logical".
> This limitation probably means that FreeBSD's boot loader isn't smart
> enough to understand and follow the logical partition/slice chain to
> locate the file system containing the kernel to be loaded.  From what
> I've read, LINUX's LILO boot loader *can* do this.  Perhaps the FreeBSD
> loader will be made smarter someday, but I'd guess that would be a low-
> priority item on the developer team's to-do list.
> 
> 
>                                   Scott Bennett, Comm. ASMELG, CFIAG
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