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Date: Mon, 19 May 1997 11:05:33 -0400
From: Charles Henrich <henrich@crh.cl.msu.edu>
To: Joerg Wunsch <joerg_wunsch@uriah.heep.sax.de>
Cc: freebsd-scsi@FreeBSD.ORG
Subject: Re: scsi library interface
References: <19970518184034.10726@crh.cl.msu.edu> <19970519103618.LH45116@uriah.heep.sax.de>
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On the subject of Re: scsi library interface, J Wunsch stated:

> As Charles Henrich wrote:
> 
> > Who wrote the scsi interface commands? (e.g. scsi_open, scsi_build
> > ..) I need to bang on them with some questions.
> 
> Peter Dufault.  He's also got a revamped library which he was asking
> people to test.  It's on hub's anon ftp area, if i'm not mistaken.

Cool.

> > Also, in general when do you use raw mode devices vs. block mode vs
> > the .ctl devices?
> 
> Buffered (`block') devices: to mount a filesystem over them.  Nothing
> else.  (Well, swapon(8) is in the same boat.)
> 
> Raw (`character') devices: any other regular (i.e. read(2)/write(2))
> IO.
> 
> Control devices: raw SCSI commands.  State of the device doesn't
> matter then, e.g. you can open a control device for an unformatted
> disk, but you can't open the raw or buffered device.

Then why is it when you start sending raw SCSI read commands to rcd0.ctl
behind which lives a Toshiba, you explode the SCSI bus, yet if you send them
to /dev/cd0c things appear to work?  (And with a plextor, both work!)  Im
confused..

-Crh

       Charles Henrich     Michigan State University     henrich@msu.edu

                         http://pilot.msu.edu/~henrich