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Thread ID: 64562 2005-12-19 14:11:00 Why HDD shows less size than mentioned? sanjoo (9446) Press F1
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413952 2005-12-19 14:11:00 Hi all,

I brought kingston 40 GB HDD. When i load OS and then i tried see the size using my computer. But it shows some thing less than 40 GB. When i contacted kingston about this. They said it calculates on 1000 intead 1024 base. Can any one explain this? Please help me to get clarify this as it sounds technical question?

Cheers,
Sanjoo
sanjoo (9446)
413953 2005-12-19 15:01:00 You're looking at the formatted size. A 40GB hard drive should read about 37GB in Windows, because the non-data stuff on the disk takes up some of the space. The "40GB" is the raw, unformatted size which is visible in the BIOS. george12 (7)
413954 2005-12-19 17:59:00 Hard Drive manufacturers ought to be tax accountants, with the creative maths they do. :rolleyes:

What they do is assume 1KB = 1000 Bytes
But 1KB actually = 1024 Bytes


So, they sell a Hard Drive of 40,000,000,000 Bytes which equals 40 GB using their maths.

However to the rest of the world 40,000,000,000 Bytes is actually 37.25 GB

40,000,000,000 Bytes / 1024 /1024 / 1024 = 37.25 GB

Where:
1024 Bytes = 1 KB
1024 KB = 1 MB
1024 MB = 1 GB


Why they do this, I don't know.
Jen (38)
413955 2005-12-19 18:28:00 They do it because the programmers shouldn't have hijacked metric prefixes for BINARY numbers. The engineers making hard drives are following the recommended usage of the IEC. Once people start using the proper binary terms like kibibyte and mebibyte there will be less confusion.

en.wikipedia.org
PaulD (232)
413956 2005-12-19 23:25:00 Discussed here before:

pressf1.pcworld.co.nz
zqwerty (97)
413957 2005-12-20 03:13:00 They do it because the programmers shouldn't have hijacked metric prefixes for BINARY numbers. The engineers making hard drives are following the recommended usage of the IEC. Once people start using the proper binary terms like kibibyte and mebibyte there will be less confusion.Ah, well that explains it. The current terms are so engrained I don't ever see it changing for the masses. I mean, 1024 Megabytes is much more attractive sounding than 1000 Mebibytes :rolleyes: Jen (38)
413958 2005-12-20 03:17:00 Discussed here before:

pressf1.pcworld.co.nz is entirely different again. That thread explains the differences between reported free space and actual free space due to the cluster size and how it is used. Windows will report a 40 *GB* hard drive as being 37.25 GB because of the difference in standard units (1000 vs 1024).
Jen (38)
413959 2005-12-20 03:28:00 Ah, well that explains it. The current terms are so engrained I don't ever see it changing for the masses. I mean, 1024 Megabytes is much more attractive sounding than 1000 Mebibytes :rolleyes:Jen... whats a Mebibyte? Myth (110)
413960 2005-12-20 03:37:00 Jen... whats a Mebibyte?Abbreviated it is MiB which we all know is Men In Black :D

Megabyte is 10E6, whereas Mebibyte is 2E10 - decimal prefixes vs binary prefixes. Confused? Join the club!

Check out PaulD's wikipedia link above.
Jen (38)
413961 2005-12-20 16:54:00 Jen... whats a Mebibyte?

now here is something interesting
2^10 1,024 = 1 KiloBytes
2^20 1,048,576 = 1 MegaBytes
2^30 1,073,741,824 = 1 GigaBytes
notice each time you add a ^10 the result goes up 10E3 (roughly)

Of course a Mebibyte is a variant way of spelling Megabyte when it is close to "Merry Christmas and ....... " which is 2^28, I wonder if there is a meganibble 2^24? I suppose in the theory books there would be.
Eric (378)
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