Re: 500 gigabyte discs
Quote:
|
Originally Posted by Powell&Pressburger
This disc was just created for the reason we are reading about it nothing more. It won't be used for consumer usage like purchasing a film or TV show. Nice press release item but alas that is all it ever will be. I can see major companies using these discs for computer tech purposes etc but not on the average consumer level.
|
Agreed, probably not.
The issue that will likely rise is this...
When you go up to 3 dimensions, you need 2 lasers focusing on 1 spot to return the proper value. Since discs are generally written in either a spiral or circular pattern you pretty much have to have a receiver of some sort in there. One laser vertical, one laser horizontal, and 1 piece receiving the "value", something has to be mechanical in nature.
This presents the issue. Once you introduce something mechanical, you introduce two further issues, latency, and accuracy.
Our friend the Hard Drive demonstrates where our problem lies. A drive has a mechanical arm that moves across a platter, trying to find the right spot. The majority of the time spent in a transfer is moving that arm, which is comparably slow to streaming off the values once it gets in the right spot. A drive is spinning 120 times per second at least, it only needs one of those rotations to get the bits.
So our first problem is that it's slow to place.
The second problem is that as more data is packed in the same area, it becomes harder to hit the proper spot to find the data. A drive today is so tightly packed that the head actually bounces around on tracks in the general area trying to find the right one. So it takes longer to find the right spot the bigger the drive is. I'm not saying today's drives are slower, but they have a harder time hitting the right spot than yesteryears drives did.
What this means with holographic media is that you have an enourmous problem with seeking. The stuff can pack bits in at phenomenal densities, but getting it back out is slower. The more stuff that's in there, the more moving around something has to do to find it.
It's *really* hard with optical media, because a mote of dust floating past can give a false reading. Whereas drives are reading magnetics, that little bit of shadow, that slight vibration, can give the wrong value. You're no longer reading in 2 dimensions, you're now in 3 dimensions, so focusing is that much harder.
To put it another way, take 2 laser pointers and crisscross the beams. Something has to be at the end of one of those beams to read the value. Then toss a ball in front of that beam, that split second is enough to give the wrong value. Try doing it while moving those beams, if you don't make multiple passes, you're registering the wrong value.
It's a non-issue with optical media, it's spinnging dozens, even a hudred times per second. It can read those value 2 or 3 times to verify without a hiccup.
It is an issue with holographic media, because you're no longer rotating the media, but rotating around the media, which is slower.
In short, it's great backup material, but our future lies in solid state memory at the moment. Just as fast, can easily reach the same densities in the same amount of time, and more reliable.
The storage possibilities are endless...at least in theory!
When would these people find time to watch (and rewatch) old soaps on disc while still catching up on their favorite, currently running ones?? I won't even go into judging the "quality" of such things 
though I must admit to having wasted portions of a summer (or two?) watching one or two such series (in part due to my then-gf) back during my earlier college days. 
Of course, back then, I also liked Short Circuit(!) and found Blade Runner to be boring-and-pointless too. 
