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Date: Fri, 3 Jan 1997 07:02:49 -0600
From: peter@taronga.com (Peter da Silva)
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To: hackers@freebsd.org
Subject: Re: more than 32 disks?
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>> with an sd3<n> problem yet. :-) It looks like there are only 5 bits for the
>> unit number. This means that one will have to make driver changes to go
>> beyond 32 units. :-(

>*sigh*  I absolutely hate fixed fields :(  *grumble*.  So whats the generic
>solution besides encoding data into the minor number?  Encode a table offset
>into the minor number and make the table dynamic?

Use a wider minor number, a wider portion of the minor number for unit,
decrease the number of bits used for things other than unit, use multiple
major numbers, or use another encoding than major/minor numbers for device
files (via devfs).

Some aspects of the System V kernel build model, where the major numbers
can be easily reassigned and the same file is used to drive the building
of the kernel and the files in /dev, are really handy. Of course devfs
makes it a point moot...