To make a bootable Slackware CD, get into the top level Slackware directory
(The one with ChangeLog.txt in it) and issue a command like this to build
the ISO image in /tmp:

mkisofs -d -D -N -R -v \
  -A "Slackware Linux" \
  -b .eltorito/eltorito.img \
  -c .eltorito/eltorito.boot \
  -o /tmp/slack.iso \
  -V "Slackware Install" .

(this command will create the '.eltorito/eltorito.boot' boot record)

The use 'cdrecord' to burn it.  (See 'man cdrecord')

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notes:
  The CD must contain at least the .eltorito and slakware directories.
  If you want to master/burn the ISO image under Windows, you're on your own.