Erase a DVD: 
------------
dvdrecord dev=0,1,0 blank=<option>

where, in general, option = fast or all.  fast should
work fine for most cases.  all will take a bit of time,
but acutally removes the data, whereas fast just deletes
location info and the old data is written over. 

Record a DVD: 
-------------

For the impatient:  There's a script to automatically burn 
a DVD.  Supply the script the name of a directory and all 
data below that directory will be burned.  Note that no 
checking of size is done - you can only burn ~4+GB of data; 
if the directory you specify contains more than that, expect 
weird things to happen.  To invoke the script: 

[user@251-016]$ DVDRec ./Directory

The details:  If you prefer to type the commands out on the 
CL, here's how.  Again, only warnings will be issued if the 
burn image exceeds the storage space on the DVD.

To create an iso image for burning: 

mkisofs -R -o burnimage.iso /path/to/data

burnimage.iso is whatever name you want to call the temp
file of your data.  Everything under /path/to/data/ will 
be packed into the iso image.  For example, if I have a 
directory MIPS0000500/ with many subdirectories that I 
want to burn I type: 

mkisofs -R -o mips400.iso ./MIPS0000400

If you want to check the iso image to verify it was properly
created

mount mips400.iso -r -t iso9660 -o loop <MOUNTPOINT>

where <mountpoint> is an empty directory.  You can then 
browse through the directory as you normally will.
To write the DVD, type

sudo dvdrecord -v -dao dev=0,1,0 mips400.iso

You can drop -v if you want (just verbose output).  You 
can also do it all as one step: 

mkisofs -R ./MIPS0000400 | sudo dvdrecord -v -dao dev=0,1,0 -

Problems: 
If you get error messages about permission to use the /dev/dvd, 
you probably haven't been added to the proper group with permission
to access the device.  All current (4/3/03) users of 251-016 and 
251-017 have permission, so if you get such an error, contact 
me (misselt@as.arizona.edu) and we'll try to fix it.