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To: "hackers%FreeBSD.ORG" <hackers@freebsd.org>
From: Larry S Lile <lslile@lexmark.com>
Date:  8 Nov 96 11:29:16 EST
Subject: Re: Pinnacle RCD Driver
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I apologize for the poor fomatting of this message, and for the waste
of bandwidth, but to make it readable I will repost it.  ( Lotus Notes 
 / Proportional Fonts / Broken Mail gateway --- Help, help I'm being 
repressed!! :)

> I am currently working on a driver for the Pinnacle RCD 5040i.  My 
> original plan was to attempt to integrate support for this device under 
> Joerg's worm driver but it differs to much from the HP/Phillips drives 
> to do this (or at least for me to be able to)  I have a pretty good start 
> on the driver and so far Pinnacle is helping me some of there less
> clearly documented scsi commands.  
> 
> What I am having trouble with and I know that these are probably 
> simple questions, but bear with me as I have never had to deal with 
> Un*x drivers from this side of the street before, are the minor numbers, 
> (cb)devsw, and the partition information.  I am also trying to write the 
> driver in such a way that I can interface directly back to Julian's cd 
> driver to give the device full functionality as both an RCD and CD.
> 
> As to minor numbers, I have seen mention of things like "5 bit unit" in
>  the cd driver, according to documentation Pinnacle sent to me the RCD 
> is an 8 bit device, but supports all cd commands that the cd driver has 
> implemented.  So do I set up the minor number in the same way Julian
>  set up the minor number for a cd or should I use the method that Joerg 
> used for the worm driver as the RCD is a worm device? Or have they 
> taken two different implementation methods because cd supports both
> block and character but worm only currently supports character.  
> 
> Second, I have seen what appear to be 2 disperate cdevsw structure 
> definitions, could some one clarify what exactly the definition of this 
> should be for me.  I have compared the implementation of sd, cd, and 
> worm but now I am totally confused
> 
> Last, I really don't get the partition stuff in the cd driver whatsoever, 
> or worse the device filesystem (DEVFS) stuff.
> 
> I am fairly sure that I can write the driver functions to operate the drive, 
> its just the interface to the kernel and low-level scsi driver that I don't 
> understand.  I have just never had to deal with them before and I don't 
> have much documentation on what is required to do so. 
> 
> Larry Lile
> lslile@lexmark.com