Topic: silly question, drive capacity

[John R]

i'm installing a new outboard drive, a seagate 400GB.  when i look at the drive, the capacity shows 372.61GB.  where's the rest?  no partition.

[bhtoque]

That's all you get.

It has to do with the way the bytes are counted up. the os seed 1 meg as 1,000 bytes, but the drive makers define 1 meg as 1028 bytes. Or something like that. I can't remember the explaination exactly.

It is summed up nicely here http://www.computerhope.com/help/hdd.htm though.

JAson

[bconnolly]

In addition to the byte mis-calculation (1 MB = 1024 KB), there is also an overhead for the file system (NTFS or FAT32).

[John R]

thanks guys.

jr

[Brian Skalinder]

Manufacturers market drive capacity using base 10, whereas your computer calculates capacity using base 2.

http://en.wikipedia.org/wiki/Binary_prefix#Binary_prefixes_using_SI_symbols_.28Non-standard_usage_but_common.29

1 GB in base 2 = 2³⁰ = 1,073,741,824 bytes
1 GB in base 10 = 10³ = 1,000,000,000 bytes

IOW, whatever GB capacity you see marketed for a HD, the actual capacity will be ~93% of stated.  In your case, 93% of 400 GB = 372 GB.

[John R]

thank you also, brian.

jr