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Date:      Wed, 15 Mar 1995 19:33:13 -0800 (PST)
From:      Poul-Henning Kamp <phk@ref.tfs.com>
To:        terry@cs.weber.edu (Terry Lambert)
Cc:        rgrimes@gndrsh.aac.dev.com, current@FreeBSD.org
Subject:   Re: newfs: sectors per cylinder (4096) disagrees with disk label (36)
Message-ID:  <199503160333.TAA09321@ref.tfs.com>
In-Reply-To: <9503160321.AA16377@cs.weber.edu> from "Terry Lambert" at Mar 15, 95 08:21:21 pm

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> > > 1.	Physical volume spanning.  Like AIX, it is useful to have a
> > > 	logical partition on which you actually build your file system
> > > 	capable of spanning one or more phical partitions on one or
> > > 	more physical drives.
> > Is this an argument for or against ?
> 
> An argument for seperation of geometry information from /dev accessable
> devices, but against seperation of them from device drivers.
> 
> Basically, there need to be devices that access the raw disk (machine
> specific) which are used to access the DOS partitions from user space
> and to mount (using a clone) do partitions without a device being
> dedicated to the DOS partition.
No.  The slice code will do this the right way.  On device in /dev
for each logical area of the disk.

> ...
> There need to be geometry "bleed through" "hints" to the upper
> layers.  In the case of a non-translated MFM or ESDI device, ROTdelay
> still has meaning.
Yes, that's why I wanted that bit of logic in newfs.

> The "perfection" of media (bad144, etc.) is handled at the middle
> layer, or in a layer between the middle layer and the first layer,
> depending on how machine specific this might get.
bad144 is a relic.  Forget it, it won't bother us for long.

I think that most of what you mention, is right as such.  I'm just not 
going to worry about it for now.  When I see the code: yes, now: no.

-- 
Poul-Henning Kamp <phk@login.dknet.dk> -- TRW Financial Systems, Inc.
'All relevant people are pertinent' && 'All rude people are impertinent'
=> 'no rude people are relevant'



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