5 ms·
Really? Assuming that the rotation speed is the same for a normal disk and this denser format, wouldn't said laser be moving over 250,000 times as much data in
by harwoodr 12y ago
Really? Assuming that the rotation speed is the same for a normal disk and this denser format, wouldn't said laser be moving over 250,000 times as much data in the same time period?
At 1X speed, a DVD's data rate is about 11Mbit/s - so at 250,000 times the density, isn't it safe to assume a theoretical data rate of 2.75Tbit/s? Of course, pushing that much data at that rate is another problem...
If my assumptions are incorrect, please let me know - I'm just trying to understand.
- tobylane 12y ago52x speed has been the limit for a long time because the outside edge of the CD gets to speeds where it could damage itself. I guess it would need a cushion, like a nearly applied (car/bike) disc brake.
- harwoodr 12y agoOkay - but I'm not talking about changing the rotational speed.
- TheLoneWolfling 12y agoYou're forgetting the square-cube law. Or rather, in this case the linear-square law. Think of each bit as a square, with side length 1/n. Oversimplifying, but the basic principle is there. The total amount of data the laser goes over in a second is proportional to n - because it's related to how long the laser takes to get from one edge of the square the the other edge. But the total amount of information stored goes up as n^2 - it's related to the area of the square. Or: to put it another way, the number of tracks also goes up when data density increases. (This also happens with hard drives over time. Recent hard drives take a lot longer to read or write the entire drive than older ones. See http://tylermuth.wordpress.com/2011/11/02/a-little-hard-drive-history-and-the-big-data-problem/ http://tylermuth.wordpress.com/2011/11/02/a-little-hard-driv... for example.)