80 minute, 700MB CDRs replaced the original 74 minute 650MB several years ago. Most CD writers made this century support them and my 2X non RW drive bought back in 1998 needed only a simple firmware update. This however, is only a slight increase in storage capacity.

Double sided disks
The double sided CDR was vaporware. If you get into the technical apsects of how CDRs work, you'll find it incredible that anyone ever thought such a scheme would actually work, yet at least one company did actually announce it, only to scrap the idea before it ever hit the market.

Double sided DVDs, on the other hand, are real and usable. They never really have caught on, however, and are hard to find, even online! As you might expect, the cost per disk was always conisderably more than twice the cost of a single sided DVD so they never became economically feasible. Aside from that, how do you label a double sided disk? It would seem that you would be limited to tiny "core" labels.

The one truly practical application would be double sided mini DVDR/RW disks used in camcorders. It could come in handy to be able to flip the disk over and continue recording on the other side.

Dual Layer disks
Dual layer disks have two layers on the same side. Most current DVD writers support them and both DVD Roms and DVD players can read them. They aren't quite double the storage, 8.4GB vs 4.7GB, and at $2.49 a piece (as of June 2007) they cost about 30¢ a gigabyte, compared to 10¢ a gigabyte for regular DVDR and 24¢ per gigabyte for a hard drive.

DL disks would come in handy if you really need to put more than 4.7GB on one disk and if the price drops to about 85¢ per disk then they would be economically comparable to DVDRs at today's prices (of course, the cost of DVDRs could drop considerably as well!). It is yet to be seen if that will ever happen.

Blu-ray
Blu-ray, AKA Blue ray and BDR is an emerging technology that could become the new standard. It was designed to hold 2 hours and 15 minutes of HDTV with enough room left over for 2 hours of standard definition bonus material. For computers thats 25GB of data on a disk the same size as a regular CD/DVDR! It does this by using a .85 Numerical Aperture (?)and a 405nm blue-violet laser which gives Blu-ray it's name. Blue Ray also has a very hard layer on top which protects the data layer(s) from scratches.

In addition to the standard discs there will be also be DL with 50GB as well as mini (8cm) with 7.8GB and mini DL with 15.6 GB. So mini BDR DL will have TEN THOUSAND times the capacity of a 3.5 inch floppy in a disk that's slightly smaller!

[I told you this would get exciting!]
This progress from the 1.44MB floppy to the slightly smaller 15.6GB mini BDR DL took place in about the time required for a newborn baby to graduate from highschool.

Being an emerging technology, Blu-ray is still a little expensive. The drives sell in the general range of $500 - $800 (think back a few years...) the standard 25GB discs sell for $13.25 each. That's 53¢ per GB, about double the cost of a 500GB hard drive.

Prices are expected to drop, however, and if the discs drop to $6.25 each then the cost per GB will be comparable to today's hard drive prices. If they drop to $2.50 each they'll be comparable to today's DVDRs. If the drives drop to less than $300 and the discs to $2 then it will be like CDRs in 1998, but with 36 times the storage per disk! Blu-ray will then be well on the way to becoming the new standard.

Could this happen by the end of 2008? It is dangerous to make such predictions, but this one is a definite possibility!
     Part five