[lug] CD burning and Crontab -e

[Tkil]

>>>>> "David" == David Willcox <acesouth at frii.com> writes:

David> This is a multi-part message in MIME format.

just for future refrence:  this is a mostly-text mailing list, and the
extra HTML copy is useless (and annoying) to me, at least.  others may
have other opinions, but generally, it seems we prefer just a
well-formatted text version.  others are free to disagree.

and the vcard crap is a complete waste.  just put a URL pointing at
your web page in a text signature at the bottom of your e-mail, and
it's less load on everybody.

David> I was told that you can't put a script in 'crontab -e' to have
David> a CD-RW burner script execute everyday at a specified time.  Is
David> this fact or fiction ?

this is basically a fiction.  the previous response (that you can put
anything into a crontab that you have permission to run normally) is
correct.

there are subtle issues involved in this particular case, however:

1. the most common linux cd-r/cd-rw writing tool, cdrecord, really
   prefers to be run as root (so it can lock down its FIFO queue).
   not a big deal; run it in the root cron.

2. using cd-rw for a backup scheme (which is what this sounds like) is
   not difficult, but you do have to deal with issues like: handling
   multi-session situations correctly, detecting "this change set
   won't fit in the rest of this CD-RW, so i need to finalize this
   disc and scream for a new one" situations, making a session image
   (iso9660?) out of the change set (i'm pretty sure you can't just
   write a tar or dump output to your cd-rw device), etc.

   so while i will flatly say that this is not impossible, i will say
   that it can easily become tricky.

anyway.  so the short answer to your question is:  it's fiction, and
question your source's level of clue.

long answer: using CD-RW in an unattended mode has many tricky
aspects, and you need to be aware of them.

good luck,
t.