DVDead? The Future of Memory is in Fluorescence!

Adas writes "We've slapped an article discussing and presenting something that could make your brand new 6X DVD-ROM drive blush in its bay. It's called FMD-ROM and is is slated to be ready for production before the end of this year. The 12mm (CD-ROM/DVD-ROM) disc version of this memory will store up to 140GB! In the future, we're looking at capacities of up to 1,4 _terabytes_ per disc, and transfer speeds of up to 1GB per second. Wipe the drool off your collar and read on here. "

Comments

Re:dvd

[Joe Rumsey]

The madness will stop when you can store the sum total of every bit of information any intelligent being anywhere has ever recorded in something too small to be seen with the naked eye.

I've looked into my crystal ball and found some comments that will be posted to slashdot the day those are announced:

"Dammit, I just upgraded to the grain of sand sized sum-total of all knowledge, and now this!"

"Can you make a beowulf cluster out of these?"

"I tried installing linux on one of these, and I STILL had to put the kernel in the first 1024 cylinders. Will someone PLEASE fix that?"

"Mine is already full of archived natalie portman posts, I need another one."

Moderate this up - This is indeed questionable.

[Christopher Thomas]

Once in December of last year (by CmdrTaco), and once even earlier. It was shot down then, and I don't see why it'd fly now.

This is quite correct. Many of the claims made were shady, and while the technology itself may be feasible after a lot of engineering, the article cited here is certainly a lot more questionable.

Logic errors picked at random, because I'm too tired to cut it to ribbons thoroughly right now:

• You won't magically make the layer-selection problem go away here.
  Previous layers will still fluoresce as your UV beam shines through them - just not as brightly. However, they will fluoresce over a larger area, conserving total luminosity. Therefore, you'd better have extremely good selectivity in your readout optics if you don't want stray light mucking things up. Depend on the previous layer bits averaging out? Bet I can find special cases that still cause problems. Summary: This is not magically superior for layering.
  
  
• Using dots of light vs. pits.
  The problems facing multi-layer pit surfaces are exactly the same as those facing multi-layer fluorescent surfaces as described above. No better, and no worse (well, a few implementation differences in error correction, but you get the idea).
  
  
• "...store data in a way that is embarrassingly similar to Thomas Edison's old gramophone records"
  Shady support. Wheels have been around for thousands of years. Does this mean that they are obsolete now that we have alternatives?
  Analogy, as well as logic, is stretched a bit thin here. Data layout is similar, readout scheme is unrelated. FMD, by coincidence, would use very similar layouts in any spinning-disc devices (I have yet to see a convincing description of how they'd make a credit-card sized solid-state device with this technology).
  

Short version: Technology is mildly interesting but nothing spectacular. DVD technology has the same potential; neither is much easier to implement. Article itself is vapour, heavy on hype and short on actual thought.

Look a little more closely(and ignore the hype)

[Anonymous Shepherd]

Some of what is mentioned in the article makes sense, and a lot of it really is just hype and excitement.

For example, if you get a nine layer disc that flouresces at 9 different frequencies, one laser could then do a read on a byte + some sort of parity at once; feed the combined signal into a fast enough demodulator, and you can effectively increase the speed of the drive by a factor of 8 over the current top of the line; a 40x CD becomes a 320x FCD. That's about 46.8 mb/s, on the assumption that the hardware demodulator can keep up with the data stream. A 5 layer disc of the same type would only be 23.4 mb/s, but that's still plenty =)

This, however, saturates the SCSI bus, excepting for the fastest/widest standards, I think.

However, this isn't all that great, as the author expects. Latency/seek on the disk would be the same, so even if you can stream data at this tremendous rate, except for linear reads, as in music, movies, or copying, it wouldn't be all that useful(any more than standard CDs and DVDs)

It is to note, however, that I can't see how one could make a writeable version of this technology; Would one need an N laser system, one for each layer? Or would we have to wait for semiconductor lasers that could adapt and change it's own active frequency based on current or voltage?

Anyway, all the FCD proposes is to apply towards CDs what has already been done for HDs; by placing disks in parallel, increase the speed of read or write, ala RAID, though in this case because it is optic, you can crowd all the data into one channel(fibre optic) until it needs to be demodulated or something...

Or am I missing something else?

-AS

Re:What about shelf life?

[ScottG]

I fear we may be wandering off topic, but according to the CD Recordable FAQ (www.fadden.com/cdrfaq/):

Pressed CD's may last as little as 10-25 years.

CDR's once recorded should last at least 75 years, but strangely only have an unrecorded shelf life of 5 to 10 years.