A brilliant idea or is it?

Just thought about something that has been nagging me for quite a while. I was browsing in my mind of mass storage devices and the immediate things that pop up at the 3 levels of storage, and the related stuff. Now, looking at ternary storage devices, right now completely monopolized by tape devices, I hit up on an idea. Why not, make the entire system (a database/storage information system) a 4 level system of storage. The tapes go back down to the 4th level, and in its place comes the set of Recordable discs. I am saying Recordable discs for the following reasons

1.) They are cheap. The cost of the disc per GB is cheaper than that of a Hard Disc. Lemme prove this point

A Typical 80GB HDD (Samsung 0802N - the best available for the medium 7200 RPM range) costs about Rs 4000 (roughly). Now that is 78.125 GB of data that can be stored, and the cost per GB is coming to 51.2Rs / GB. Now thatz kinda costly coming to think that a CD - 700 MB (0.7GB) costs you roughly about 10-20 bucks a piece. Extrapolating it, it would be 28.57Rs / GB.

2.) They are considered Direct Access Mass Storage Devices.

So, just moving on, I feel that if we can design a fast CD changer/dedicated multiple reader/recorder system, the 3rd level of storage, can be much faster than a magnetic tape storage system right now. This would solve the last level of slow storage.

Disadvantages/ discrepancies that i thought about
-> Itz cumbersome, writing just about only 0.7GB :D writing time is 3 mins roughly for the same
-> Managing a lot of CDs would be weird, coz you have to make a dedicated catalog manager, as compared to large amount of GBs onto one Tape.
-> The maintenance of the system would be costlier especially replacing write and read lenses.

But, with the advent of DVDs and Compressed CD formats, I think we might just be able to pull it off. Anyways, was just musing and thought where else to put this idea forward that SIG 9 - ;)