Subject: Re: VPS mailing list, BSD interest?
To: Poul-Henning Kamp <>
From: Kevin P. Neal <>
List: tech-kern
Date: 10/02/1996 01:01:48
At 09:44 PM 10/1/96 +0200, Poul-Henning Kamp wrote:
>In message <>, Jason Thorpe writes:
>>On Tue, 01 Oct 1996 09:53:02 -0700 
>> "Justin T. Gibbs" <> wrote:
>> > Actually, I don't think it is.  CCD should be relying on information stored
>> > in a private area of the disk to determine what stripe sets what partitions
>I agree.
>>Just where do you propose to keep this information?
>>(Hint: it's going to be machine-dependent.)
>not if done right.
>I know at least one VolMgr that will search the first X Mb of the disk looking
>for a signature...


>>When you say "open the partition", which partition are you opening?
>>(Hint: if you're opening /dev/sd0a, then you have to put all kinds of
>>crap to find the "ccd block" in the SCSI disk driver, and the IDE disk
>>driver, and the Xylogics disk drivers, and...)
>Jason, you clearly havn't seen the light.  I'll compose an email with
>my design idea, and send it but it may not be until tomorrow that I
>get to it.

(if you give a lengthy explanation, could you forward it my way? Please?)

Question: Why do block devices know about partitioning? Wouldn't it make
more sense to have a "disk" driver, that has a list of disks and disk
drivers attached to it? This way the user doesn't have to deal with
sd0 vs wd0 vs xy0 vs whatever, they work with /dev/disk0a. The "disk"
driver would have an ioctl that passed up the ASCII id string returned
by disks, or by the disk driver itself (or some other identifier, you
decide). The "disk" driver could deal with partitions in it's own manner.

What am I missing here? 

>CCD is way to narrowminded.

Monkeywrench! How can you have an LFS root partition (never mind the LVM
stuff), and still be able to boot on, say, a Sun3? I mean, doesn't the
boot prom have to be able to read the file system to load the loader
program? Where are you going to stuff boot.sun3? Or a DECstation kernel?
This could get ugly. 
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