[Sussex] Problem writing image to CD

[Brendan Whelan]

Thanks for the responses.

I don't have the system powered up at the moment.
I had wondered about some sort of time out problem -where can I find the
settings for apm or acpi?
I am only recording at x4 on a modern 3GHz system - is there a way of
finding out the maximum speed at which I can record?

Thanks,  Brendan
> down
----- Original Message -----
From: "Stephen Williams" <sdp.williams at btinternet.com>
To: "LUG email list for the Sussex Counties" <sussex at mailman.lug.org.uk>
Sent: Sunday, October 09, 2005 12:50 PM
Subject: Re: [Sussex] Problem writing image to CD


> On Fri, 2005-10-07 at 21:28 +0100, Brendan Whelan wrote:
> > Hello,
> >
> > I have created a backup shell script which exports a database, gathers
> > files, creates a CD image file and then writes it to a CD.
> > The shell script is then scheduled to run during the night. There are
> > a pair of, logically identical, systems one a Dell tower and the other
> > a Dell rack mountable servers. (Fedora Core 3 is used on both
> > systems.) The shell script works perfectly on the tower system but on
> > the rack mounted machine the CD writing fails. The image to be copied
> > is only about 360Mb, I have used different manufacturers CDs but the
> > problem persists. I changed the CD drive but the problem persists.
> >
> > I have taken an image copy of the offending system and placed it my
> > test system with the same type of CD writer which is in the rack
> > mountable system.
> > To simplify the problem I created a shell script which just
> > contains the line which writes to the CD.  When I run the script in a
> > terminal window it works. When I run it as a cron job it fails. The
> > led on the CD writer flashes for a number of minutes and then goes on.
> > The CD cannot be unmounted and the only way to extract the CD is to
> > either power the system down and back up or to use a paper clip to
> > release the CD drawer. (As an aside small image files can be written
> > to the CD using a cron job.)
> >
> > Any suggestions as to what might be causing the problem or how I could
> > find out more information.
>
> My suspicions centre around power saving. Is apm or acpi set to power
> down the CD-RW in the rackmount box and not in the tower box for
> example.  Perhaps the user account under which the cron job is run needs
> sufficient authority to be able to prevent power down signals from
> affecting the CD-RW when a job is in progress? Might be something worth
> investigating.
>
> Steve W.
>
>
> >
> > Thanks, Brendan
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>
>
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