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Date:      Fri, 14 Mar 1997 09:02:13 +0100
From:      j@uriah.heep.sax.de (J Wunsch)
To:        freebsd-current@FreeBSD.ORG
Subject:   Re: worm0 and cd imaging
Message-ID:  <19970314090213.KU02331@uriah.heep.sax.de>
In-Reply-To: <199703140533.QAA12400@genesis.atrad.adelaide.edu.au>; from Michael Smith on Mar 14, 1997 16:03:17 %2B1030
References:  <199703130858.DAA06544@hda.hda.com> <199703140533.QAA12400@genesis.atrad.adelaide.edu.au>

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As Michael Smith wrote:

> Of curiosity, how many SCSI CD/burner devices support the scsi COPY
> command?  This would make for completely hands-off duplication, which
> would be even better 8)

I don't know of any, and given the rather complicated handling in
preparation of burning a track, it probably wouldn't make too much
sense, too.

But people often tend to overestimate the CD-R data rates anyway, just
only since these drives have some tight timing requirements.  The rate
itself is fairly low, most devices still can't burn faster than 300
KB/s (for CD-ROM data, that's 350 KB/s audio).  This is a pretty low
rate if you compare it to a disk, or the bandwidth of a SCSI bus.
Hence, the overhead of piping all the data through the CPU once isn't
noticeable.

-- 
cheers, J"org

joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE
Never trust an operating system you don't have sources for. ;-)



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