Crazy Matshita Combo Drive

Before worrying about firmware, check that these disks aren't readable in another Mac running the same operating system. I'd want to find out if the reason it isn't mounting certain CDs is because they were burnt a non-standard format, or are made a non-standard thickness, size, or are copy-protected, or of poor quality and worn out as these articles show that these drives can be particular about what they will mount:

http://docs.info.apple.com/article.html?artnum=58641
http://docs.info.apple.com/article.html?artnum=106882

Mac OS X can only read certain UDF formats, ISO 9660 formats, and all Mac formatted CDs. And the quality of the media may also be in question. Many disks are not made from the standard dyes of Verbatim, Imation, Kodak, or Sony, and have been written up as wearing out quicker on http://www.macintouch.com/cdrfailure.html

In addition, thanks to those articles, I don't write on the label side of the disk and only buy media in jewelcases and use the inserts of the jewelcase to tell what's on the disks. It may be overzealous on my part to take all those precautions, but I only do since others have experienced issues when not taking all of them.

If none of those appear to apply, and the disk is readable in another Mac running 10.4.2, maybe I'd consider the firmware, but I'd only run it after verifying others have run it too without any bad side effects.

http://www.xlr8yourmac.com has a good database of drives and what people have done with them on Macs.

Good luck!

Open the Applications -> Utilities -> Terminal, and type:

drutil info

followed by a return key, and paste its output there. I have a sneaking suspicion your drive can't read DVDs.

Interconnect: ATAPI

SupportLevel: Apple Shipping
Cache: 2048k
CD-Write: -R, -RW, BUFE, CDText, Test, IndexPts, ISRC
DVD-Write:
Strategies: CD-TAO, CD-SAO, CD-Raw

My suspicion was correct. Your internal drive can't read DVD of any format.

Not that drive. The status clearly shows that it does not have the ability to read DVDs. Mine for instance says:

Vendor Product Rev
MATSHITA DVD-R UJ-825 DBN7

Interconnect: ATAPI
SupportLevel: Apple Shipping
Cache: 2048k
CD-Write: -R, -RW, BUFE, CDText, Test, IndexPts, ISRC
DVD-Write: -R, -RW, +R, +RW, BUFE, Test
Strategies: CD-TAO, CD-SAO, DVD-DAO

And I have an iMac G5 as well.

So I think that you need to see if somehow you got the wrong drive installed by mistake. The clue was the fact its name was CD-RW. Combo drives which can read DVDs are DVD/CD-RW.

I realize your drive is not a Superdrive. However, I would have thought that drutil's output would mention its ability to read DVDs if has that ability. Regardless, since you appear to have the ability to read DVDs, that's obviously not the case here, and has left me stumped. Since the disks are readable on an external drive on the same operating system, it suggests one of a number of things could be wrong with the internal drive:

- dust
- lense got dirty
- sensitivity to how well balanced disks may be (uneven surfaces can cause problems with some drives)
- as you suggest the firmware, which I've provided a link to where you might find it in an earlier post.

If the machine is under the 1 year hardware warranty or AppleCare I'd try to have the extended hardware test run from the installer disks which came with it to see if they detect anything wrong. It is bootable using the Startup Manager:

http://docs.info.apple.com/article.html?artnum=106178

And then call AppleCare with whatever results you get. I wouldn't be too quick to attempt to upgrade the firmware. Make sure it isn't a hardware issue with the drive first.