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Question

How do I compute the capacity of a hard disk?

Answer 1

+6 A:

The answer is

heads x cylinder x sectors x 512 (typical size of one sector in bytes)

so this is

12 x 17000 x 400 x 512

which is the same as

12 x 17 x 1000 x 4 x 100 x 512

and

100 = 10^2
1000 = 10^3
10^2 x 10^3 = 10^5

As you want the capacity, you don't need any times here.

A reference for the 512 bytes can be found at Wikipedia, for example (and it also has a similar example with the same formula a bit below).

schnaader 2010-01-13 18:54:49

beat me to it :)

BlueRaja - Danny Pflughoeft 2010-01-13 18:56:26

Was pretty lucky that I saw the question almost as it appeared - I'll wait a bit on the next one so you can take it ;)

schnaader 2010-01-13 18:57:29

+1 with caveat, I think heads should really be the platters x 2 - although normally you would expect 1 head per side of a platter it isn't guarenteed.

Andrew 2010-01-13 18:59:01

See the Wikpedia link: "Naturally, a platter has 2 sides and thus 2 surfaces on which data could be manipulated; usually there are 2 heads per platter--one on each side, but not always." So I guess we can assume that and as the number of heads is given, I chose to use that one.

schnaader 2010-01-13 19:02:58

But of course you're right that it's still an assumption, as well as the sector size of 512 bytes which will perhaps change to 4096 bytes in the near future.

schnaader 2010-01-13 19:04:16

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How do I compute the capacity of a hard disk?

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