CD Duplication using Linux

[Lennart Sorensen]

On Thu, Mar 16, 2006 at 07:24:48PM -0500, phiscock-g851W1bGYuGnS0EtXVNi6w at public.gmane.org wrote:
> Faced with the necessity of duplicating multiples of 100 CD discs, my
> thoughts are turning to CD duplicator towers. Has anyone put together one
> of these? Using Linux to run it, of course.
> 
> Is this a straightforward exercise of slapping the hardware into a box or
> are there Issues? Is it straightforward to configure? Can the operating
> system stream data to say, 4 writers at once?
> 
> Advice or indirect address to advice much appreciated.

Well things to keep in mind:

Unless your devices support disconnect, you can only run one writer per
channel.  So only put one writer per ide channel, and don't put other
devices on the channel either.  If it does support disconnect, you might
be able to get away with it, but it is probably not a good idea.

A DVD writer takes about 1.3MB/s * the speed it writes of sustained
data transfer.  Make sure your disk system can andle that.  So if you
have 8x drives, and run 4 drives, you will need to sustain at least
40MB/s from your filesystem, unless you do something clever.

If you are writing identical disks, you might be able to do something
clever to avoid having to have each writer run by a seperate program,
all reading from the disk.  At the same time if they are started at the
same time and all write the same disk, the data is likely to be cached
which will reduce the disk load too.  If you had enough ram to store the
image in tmpfs then it would be even less disk io load.

The way the burner systems I have seen do it, is to simply transmit
identical data to all the drives at once, or they have a dedicated
controller with a channel to each drive that takes care of getting the
data there (I have only seen that on a system with 4x CD drives, which
is only 600KB/s).

Things like http://www.ultera.com/c-multimaster.htm just appear as one
drive, which makes it much simpler for the system, and more efficient.
They also cost more.

Len Sorensen
--
The Toronto Linux Users Group.      Meetings: http://tlug.ss.org
TLUG requests: Linux topics, No HTML, wrap text below 80 columns
How to UNSUBSCRIBE: http://tlug.ss.org/subscribe.shtml