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Date:      Tue, 1 Oct 2002 16:12:08 +0000
From:      "Weston M. Price" <wmprice@direcway.com>
To:        freebsd-questions@freebsd.org
Subject:   Re: Character Devices vs. Block Devices
Message-ID:  <200210011612.08538.wmprice@direcway.com>
In-Reply-To: <200210011519.59430.wmprice@direcway.com>
References:  <200210011519.59430.wmprice@direcway.com>

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So, given this, I am assuming that hard drives are treated as raw devices=
=20
exclusively? That is, no intermediate buffers are maintained between the =
user=20
process and the device:

=46rom The Design and Implementation of the  4.4 BSD operating system:

"The character interface does not copy the user data into a kernel buffer=
=20
before putting then on an I/O queue. Rather, it arranges to have the I/O =
done=20
directly to or from the address space of the process. "

Is this valid on FreeBSD?=20

Regard,

Weston

On Tuesday 01 October 2002 03:19 pm, Weston M. Price wrote:
> Hello,
> =09A quick ls of my dev directory revealed that each one of my hard dri=
ves is
> considered a character device by the system. Example:
>
> crw-r-----  2 root  operator  116, 0x00010002 Aug 19 16:09 /dev/ad0
> crw-r-----  2 root  operator  116,   0 Aug 19 16:09 /dev/ad0a
> crw-r-----  2 root  operator  116,   1 Aug 19 16:09 /dev/ad0b
> crw-r-----  2 root  operator  116,   2 Aug 19 16:09 /dev/ad0c
> crw-r-----  2 root  operator  116,   3 Aug 19 16:09 /dev/ad0d
> crw-r-----  2 root  operator  116,   4 Aug 19 16:09 /dev/ad0e
> crw-r-----  2 root  operator  116,   5 Aug 19 16:09 /dev/ad0f
> crw-r-----  2 root  operator  116,   6 Aug 19 16:09 /dev/ad0g
> crw-r-----  2 root  operator  116,   7 Aug 19 16:09 /dev/ad0h
>
> What I am confused about, aren't hard drives treated as block devices o=
n
> most systems? What am I missing?
>
> Regards,
>
> Weston
>
>
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