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Date:      Tue, 23 Mar 1999 10:27:35 +1030
From:      Greg Lehey <grog@lemis.com>
To:        Roelof Osinga <roelof@eboa.com>
Cc:        freebsd-questions@FreeBSD.ORG
Subject:   Re: Have crashed, won't travel
Message-ID:  <19990323102735.N442@lemis.com>
In-Reply-To: <36F6A64E.3DED5FB6@eboa.com>; from Roelof Osinga on Mon, Mar 22, 1999 at 09:21:34PM %2B0100
References:  <19990316174710.H429@lemis.com> <36EE54A4.8DC53017@eboa.com> <19990317093436.G429@lemis.com> <36EFC56A.ACBFB0A7@eboa.com> <19990318100818.L429@lemis.com> <36F1BDBB.E9E4F323@eboa.com> <19990319150941.U429@lemis.com> <36F2ABBF.9B789EDB@eboa.com> <19990320100004.J429@lemis.com> <36F6A64E.3DED5FB6@eboa.com>

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On Monday, 22 March 1999 at 21:21:34 +0100, Roelof Osinga wrote:
> Greg Lehey wrote:
>>
>>> Could you run that by me again. If /dev/wd0s1g is the device holding
>>> the structure I need to manipulate then what is the device I should
>>> give as parameter to fsdb?
>>
>> /dev/rwd0s1g.
>
> Aarrgghh!! The *R*! As in 'raw device'! Of course. Sorry. Don't know
> why I couldn't see it or remember the difference. Just now it hit me.
>
>> Well, in fact we have a block device interface and a character device
>> interface, and they both talk to the same device.  The difference is
>> that the block interface is buffered and the character interface
>> isn't.
>
> What's in a 'r'? That a device, by any other name, may drive as sweet.
> To r or not to r, that is the question!

To cache or not to cache is the real question.  Raw devices write
straight to the device; block devices go through the buffer cache.
Sometimes it makes a difference.

Greg
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