55GB HD out of 60GB....eh? dont seem quite right..

  professor 16:51 04 Jul 03


put a quick post in a thread a while back...just got around to reading it! so anyway, the reason I ask is because I format HDD a lot and HDD's of my capacity (60GB) always come out formatted capacity of 58GB or so, so i cant help but feel im missing somthing on mine :o(

my HD is a Seagate Barracuda ATA100 7200rpm Access time 8.2ms and a 2MB cach

(this isnt a normal Barracuda its a special OEM version hence the faster access time and larger cach,although the cach has been upped to 2MB on the normal versions as well now)

so anyways, was just wondering if seagate has its own fromatting utility i dont know about, had a look around doesnt seem to be anything..but i could be missing somthing, which is why im asking. after all they say if you dont ask you wont get.


  Magik ®© 16:54 04 Jul 03

I have the same drive, and.yes, they do come out at about 57/58 gb, format and partition takes a fair bit...

  expertec 17:01 04 Jul 03

I think the HDD mfrs measure a GB as 1,000,000,000 bytes, but an OS measures it as 1,073,741,824 Bytes.

  expertec 17:03 04 Jul 03

a 60GB drive is actually about 55.8 GB

  DieSse 18:18 04 Jul 03

If you look in the drive properties in Windows, you will see both measuring systems in use. My 80Gb drive (in two partitions) listed at

80015454208 bytes = 80Gb


74.4 Gb

It's the same drive - two numbering systems!

  professor 22:08 04 Jul 03

seems like im stuck on 55gb then....will do a bit more hunting will post back

  powerless 22:10 04 Jul 03

Would you kindly post the maths?

1000 and 1024

  DieSse 23:09 04 Jul 03

1024 cubed = 1073741824

80 divided by 1073741824 = 74.5

  DieSse 23:57 04 Jul 03

PS - it all origintes with binary, where 2¹º = 1024

To make things simple to the lay men, manufacturers use "decimal" values for large hdd sizes but the OS uses the actual binary value. i.e. 1kb is actually 1024 bites, so those 24bites accummulate for each kb and by the time you get to 60Gb that is a huge number of 24kbs Work it out, you'd be surprised.

  faichfolds 00:19 05 Jul 03

Just a bit puzzled with the maths.

Why did you cube 1024?

ANd Why does 80/1073741824= 74.5

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