external hard disk

  • Thread starter Thread starter dkettles
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dkettles

Got a "120Gb" external usb drive, yet when i look at it
in various ways, it only shows up with 115Gb usable
space. Nothing on it at all at this point, and it is
formatted Fat32, I'm planning on formatting it NTFS (I
run XP Pro) and when I prepare to format it in various
ways, it only shows the size as 115Gb. Not that I'm
going to quibble over 5 gig because I doubt I'll ever
fill up 100 gig. I was just curious why this happens,
thought it might be a disk size limitation or something
but it appears that Fat32 supports up to something like 4
terrabytes. I didn't even look to see what NTFS could
handle. Any thoughts on this?
 
"dkettles" asked
Got a "120Gb" external usb drive, yet when i look at it
in various ways, it only shows up with 115Gb usable
space. Nothing on it at all at this point, and it is
formatted Fat32, I'm planning on formatting it NTFS (I
run XP Pro) and when I prepare to format it in various
ways, it only shows the size as 115Gb. Not that I'm
going to quibble over 5 gig because I doubt I'll ever
fill up 100 gig. I was just curious why this happens,
thought it might be a disk size limitation or something
but it appears that Fat32 supports up to something like 4
terrabytes. I didn't even look to see what NTFS could
handle. Any thoughts on this?
Click to expand...

Hi

You are not missing any space - although the drive manufacturer could be
clearer. For drive manufacturers 1,000,000,000 bytes = 1 Gb, whereas an OS
will regard 1,073,741,824 bytes as 1 Gb. (It's a decimal V binary thing)

The best way to see this is in XP. With XP installed, open My Computer,
select the appropriate drive and right-click, select properties... beside
'capacity' you will see the total number of bytes on your disk and to the
right the number of Gigabytes.

For example, on my 120 Gb drive I have 120,023,252,992 bytes... which is
also listed in disk properties as a capacity of 111 Gb.

The Hard Drive manufacturer refers to the 'bytes' total in my case as
120Gb... and, in purely decimal terms, it is - 120,000,000,000 bytes.

The 111 Gb is what the operating system (XP in this case) 'sees'... because
the OS calculates the storage in binary terms... 1024 bytes as 1 Kb, 1024 Kb
as 1Mb, and 1024 MB as 1 Gb.....

so in my case 120,023,252,992 / 1024 / 1024 / 1024 (that's bytes =>Kilobytes
=> Megabytes => Gigabytes) is 111.78 Gigabytes as far as the computer is
concerned. (The drive capacity may only show the first 3 digits.)

Neither calculation of the disk size is 'wrong' ...... they are equivalent.

In your case, the drive capacity of 120,000,00,000 bytes (or close to that
value) is being be referred to by 'My Computer' as 115Gb after the above
calculation - You're actually doing quite well with that capacity.

Of course, by using the decimal definition drive manufacturers are only
obliged to provide 120,000,000,000 bytes when they claim a drive size of
120Gb.

Hope that helps
Pete
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Forget the hypothetical limitations, the facts are simple

You cannot format a volume larger than 32 GB in size using the FAT32 file system in Win2K/XP.

The Win2K/XP FastFAT driver can mount and support volumes larger than 32 GB that use the FAT32 file system (subject to the other limits)

Again, the restriction is the Format tool in XP.

This behaviour is by design. Microsoft recommends using NTFS for partitions greater than 32GB.

If you need to format a FAT32 partition greater than 32GB, you will need to do it under Windows 98/SE/ME
 
Thanks to all, I knew there was a "logical" explanation for the perceived size difference, I just couldn't find one.
 
"DK" responded
Thanks to all, I knew there was a "logical" explanation for the perceived
Click to expand...
size difference, I just couldn't find one.

Happy to help clear up any confusion.

Pete
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