*BSD News Article 16122


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From: deraadt@fsa.ca (Theo de Raadt)
Subject: Re: Naming convention for tty-like devices
In-Reply-To: peter@NeoSoft.com's message of Tue, 11 May 1993 09: 31:29 GMT
Message-ID: <DERAADT.93May11133023@newt.fsa.ca>
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Organization: little lizard city
References: <1993May7.140046.1826@gmd.de> <C6pI6r.6AB@sugar.NeoSoft.COM>
	<C6q296.3D9@BitBlocks.com> <C6uvsI.9uo@sugar.NeoSoft.COM>
Date: Tue, 11 May 1993 20:30:23 GMT
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In article <C6uvsI.9uo@sugar.NeoSoft.COM> peter@NeoSoft.com (Peter da Silva) writes:
   I don't like the tendency in BSD to have the primary name for a partition or
   device pretty much arbitrary. It bugs me on the Suns at work, that the device
   at SCSI address 4 might be /dev/rst0 or /dev/rst1 depending on what SCSI
   address 3 is. I'd rather make /dev/rst/0t4 (controller 0 target 4) the main
   name, and create a link to /dev/tape.

1. There isn't enough room in the minor number.

  You need to have 3 bits worth of lun, 3 bits worth of scsi id, 3 bits
  worth of partition information, and i figure 2 bits of controller number.

  That's 3+3+3+2 == 11 bits that need to be stuffed into an 8 bit minor
  number.

2. There would need to be many more files in /dev

   The most versatile scenario I can think of needs 2^(1+2+11)=16K files
   in /dev
	{raw, or not}{disk,tape,cd,other}{0-3}{0-7}{0-7}{a-h}.

3. If you want to, the NetBSD system allows you to freeze the controllers
   to exactly where you want. Feel free to go look at how it's done.

 <tdr.
--

This space not left unintentionally unblank.		deraadt@fsa.ca