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Credit Card sized 5GB HD to arrive late this year
An anonymous reader writes "PC World reports in this article:
"The card actually has moveable parts inside its thin shell," says Bill Heil, vice president of StorCard.
A spinning wheel made of Mylar is engaged when the card is inserted into a StorReader, a USB-connected drive or PC Card that reads and writes to the StorCard. The reader is expected to retail for under $100 and the cards for under $15 each, Heil says.
The StorCard and StorReader are scheduled to become available in the second half of 2003."
According to the storcard website these cards have a datarate of 5Mbytes/sec the rotational speed is 3600 rpm and the average access time is 15 msec. All taken from the overview of the StorCard from the campany website.
This site mentions a 5Mb/s transfer rate which I guess would be more than enough for DVD movies.
However, it says that this figure is for the 100Mb version and that it "scales" to the 5Gb version. What does that mean, I wonder? It will be 50 times faster for the 5Gb version? I don't think so, somehow - 50 times slower? That might be pushing it for DVD usage at 100Mb/sec..
Q.
They have a very interesting white paper explaining how they`ve managed to make HD compliant disk without having it in an airtight sealed container. Clever stuff.
"Come," called the old man, "come now or you will be late." "Late?" said Arthur. "What for?" "What is your name, human?" "Dent. Arthur Dent," said Arthur. "Late, as in the late Dentarthurdent," said the old man, sternly. "It's a sort of threat you see." Another wistful look came into his tired old eyes. "I've never been very good at them myself, but I'm told they can be very effective."
From StorCard.com: The StorCard has the flexibility and form factor of a credit card and conforms to ISO 7816-1 including mechanical flexibility along the longitudinal and transverse axis without damage to the IC or the magnetic recording medium.
I am a leaf on the wind. Watch how I soar.
Rotational intertia (or, as I've always heard it called, the moment of inertia) is indeed a property of the object, just like mass is a property of an object. Its value depends on how the mass is arranged, though -- a solid disk and a hoop which both have the same mass and radius don't have the same moment of inertia.
You're right that angular momentum depends on rotational speed (omega), but it also depends on the moment of inertia. That's the I in your formula.
Nevertheless, as another poster pointed out, the mylar disc is small (moment of inertia goes up as you put more mass further away from the rotational center) and lightweight, so angular momentum effects will undoubtedly be tiny.
You're wrong. Well, you're right if you're talking about DVD-R which has a maximum capacity of 4.7GB but pressed DVDs can contain a LOT more (up to 17GB), considering they can be multilayered and double-sided whereas DVD-Rs are only SL/SS (Single Side/Single Layer).
Here's a table representing the various combinations and respective capacities (googled the info from this page):
DVD-5 (SS/SL): 4.38 gig (4.7G) of data, over 2 hours of video
DVD-9 (SS/DL): 7.95 gig (8.5G), about 4 hours of video
DVD-10 (DS/SL): 8.75 gig (9.4G), about 4.5 hours of video
DVD-14 (DS/ML): 12.33 gig (13.24G), about 6.5 hours of video
DVD-18 (DS/DL): 15.90 gig (17G), over 8 hours of video
DVD-RAM (SS/SL): 2.40 gig (2.58G)
DVD-RAM (DS/SL): 4.80 gig (5.16G)
As you can see, we'll have to wait a bit more for a solid-state competitor to the DVD...
Cheers,
max
-- It's always darker before it goes pitch black.
Erm. Mylar is also what film (as in what goes through the projector at your local megaplex) headers are made of (the actual film is usually polyester).
Some speakers have their active surface made of Mylar.
Light, yes. Flimsy, not necessarily.