cdrecord problem

["Thomas Droege" <tdroege2@earthlink.net>]

I am writing backup disks with the following (in perl):

system "mkisofs -R disk1 | cdrecord -v fs=6m speed=12 dev=3,0 -";

I just copied this line from the man pages and figures out what the dev
should be.  

The CD recorder is a 32x device for write.  the sub directory disk1
contains 80 ea. 8 megabyte images.  The CDs I am using are rated at 24x.  

About once a directory write, one of the files gets written as a directory.
It is then unreadable.  At least for me and the utilities that I have
tried. The buffer never gets below 97%.  Sometimes it writes garbage as the
CD directory.  An ls gets garbage that I can recognize as part of a fits
header.  I have tried recording at different speeds.  24x gets mostly
garbage.  12x gets about 1 file per 80 file block as a directory.  All but
the file shown as a directory are readable by Gimp.  The computer is a 1.5
Ghz dual processor Athelon.  

I recall seeing this problem using xcdroast in the previous Mandrake 8.1. 
I am now using 9.0.  

I seem to be able to record perfectly every time from the same directory
"on the fly" using xcdroast at 24x (the CDs are rated at 24x).

Has anyone seen this problem and can recommend what I should do?

Tom Droege