When I upgraded my ASUS N53SM-ES72 laptop to Ubuntu 14.04 last April the CDR/DVDR drive in it suddenly became read-only. There were no problems before. It reads disks just fine.

Ideas on how to fix or what to look for?
thanks,
Chris

What have you got in /etc/fstab for the cd/dvd drive? It will look something like this:

You can look in at 'man mount' for options.

The CDR/DVDR means read only drives. And CDRW/DVDRW means writable drives.

Also you use a burner software to write a disc or a packet writing setup to write.

The mount for the drive isn't in fstab.
I note the "read-only" from the disks utility which lists the drive as "Slimtype DVD A DS8A8SH (KAA2)" at device: "/dev/sr0 (Read-Only)", but I suppose it would need to SEE a blank disk to know it's not read only, if even that. I never paid attention to what it might say with a working disk until now.
Oddly, I just put a blank CD in and it saw it and appeared to want to let me burn to it. Being curious, I ejected the CD and reinserted it, and now it does not see that blank. It's the first time I've even tried in over a month.
I tried a second blank, still not seeing it. This seems more like a hardware failure, but it still reads written disks just fine.
The disks util did show the blank as a writable medium... for that one time.

This is just strange. I have laptop CDRW drives that are 10 years old that don't have any issues, so it would be terrible that this one, only 3 years old, has issues.

veerain... CDR is cd-recordable, CDRW is a rewritable CD. Do they even make non-burner CD drives for laptops anymore?

Sorry, I got confused. The drives which only reads but doesn't support writes are labeled as CDROM or DVDROM.