Subject: Partitioning should stay the same
To: Chris G Demetriou <Chris_G_Demetriou@LAGAVULIN.PDL.CS.CMU.EDU>
From: Richard Wackerbarth <>
List: macbsd-development
Date: 01/27/1995 07:12:45
Actually, I thought that there was an ANSI Standard for partitioning scsi
drives so that multiple systems could co-exist.

But in any case, what we have is a general attitude that there is a (vendor
specific) defacto standard for disk formats. We are attempting to place the
NetBSD logical devices as subdevices under that higher scheme.

>What if, in linux, what if you want to have seperate root,
>/usr, /var, /a, /b, and swap partitions _ALL ON THE SAME DISK_?
>you're out of luck, if you're using _ONLY_ the PC bios
>partitioning scheme.

The PC bios scheme is inferior to the A/UX scheme. Don't complain because
you had to live in shackles. What if on NetBSD/386, I want to have /usr
/var /a /b /c ... /z. I like smaller partitions on my 4gig drive. By
unmounting the ones that are not in use, I help protect the system from my

IMHO, neither approach is "clean" What you really have is:

1) The random access device controller(s) = Pick one.
2) The device = Pick one.
3) The Master Partitioning scheme = (Mac, DOS, Raw) Match one
4) The Particular Partition = Pick one
5) The NetBSD subpartitions = Find the appropriate one
6) The file system organization.
7) The particular kernel instance.

>the per-access complexity of the two schemes is _identical_, and the
>complexity of the code used to 'bootstrap' each scheme is a fair bit
>simpler for the "many in one" method.

Simpler is always at the expense of generality.

>And what NetBSD/mac68k has _RIGHT NOW_ is a weirdo partitioning scheme.
What BOTH have is a vendor-biased partition scheme with a NetBSD system

>It overloads vendor-specified partition id's.
You overload a single partition.

In both cases vendor partitions create a sub-device structure.
The NetBSD partitions are a sub-sub-device level.
In the case of NetBSD/mac, they REQUIRE that each logical drive be on
different sub-devices. In your case, you REQUIRE that they all be in the
SAME one.

Neither scheme is perfect. In both cases, I should be able the specify the
particular logical devices that I want to use.

It is appropriate to be able the have the flexibility to go either way.

When booting, I need to specify both the kernel to load and the initial
virtual root of a file system. They might be in very different locations,
even on different types of media and different file systems under that.