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sabre364

macrumors member
Original poster
I have a 250gb hard drive, evidenced in the first picture...after formatting I have 232 gb to play with.
cvy08pyw0zko42kxr4dh.png


However, using whatsize I noticed that my mac HD has only 32 gb of stuff on it, and the bootcamp windows HD has 27 gb of stuff. So why is my MAC hd saying I have 59 gb used??? Shouldn't it say I only have 32 gb used?

jgxwxtx64mhsz4lo0oxl.png
 
Know, that HDD manufactures advertise their drives with 250 000 000 000 bytes and just divide that by ( 1000 (KiloByte) x 1000 (MegaByte) x 1000 (GigaByte) ) instead of the accurate divider being 1024.
So 250 advertised GB are really 232 GB.

Maybe try Disk Inventory and see if it manages to get other results for your Mac HD's used space.
 
No to saying "250 GB is really 232 GB".

250 GB is really 250,000,000,000 bytes.

That's why I said "250 advertised GB".

If GB stands for GigaBytes, then 250063733391 bytes are not 250 GB as the manufactures say, as they use the decimal system, instead of the correct binary system, which uses 2 digits: "0" and"1".
To get from byte to KiloByte (KB - kb stands for kilobit), the engineers of the binary computer systems devised 2^10=1024 for better calculation, which is roughly equal to 10^3=1000 (kilo).
So 250063733391 B (bytes) are divided by (2^10)^3 to get to GigaByte (GB), which calculates to 232.89 GB.

Or what are you getting at?
 
Snow Leopard will work around this problem by using SI units. Your 250 GB drive will show up as 250 GB if you upgrade to SL.

spinnerlys, I think what cube is getting at is that "giga" is an SI prefix and means "1000000000".
 
That's why I said "250 advertised GB".

If GB stands for GigaBytes, then 250063733391 bytes are not 250 GB as the manufactures say, as they use the decimal system, instead of the correct binary system, which uses 2 digits: "0" and"1".
To get from byte to KiloByte (KB - kb stands for kilobit), the engineers of the binary computer systems devised 2^10=1024 for better calculation, which is roughly equal to 10^3=1000 (kilo).
So 250063733391 B (bytes) are divided by (2^10)^3 to get to GigaByte (GB), which calculates to 232.89 GB.

Or what are you getting at?

It's not "as advertised". The correct usage of the prefix "giga" is decimal. If you want to count in binary, you should use the binary prefixes, "gibi" in this case.
 
Ah, now I understand. I think.
I wasn't aware of this "problem", being that giga is only used for the decimal system and gibi for the binary.

So if I want to use the terms correctly, I have to say/write I have 232.89 gibibyte of storage or 250 GigaByte?

But are those "bibyte" terms actually used somewhere?

That adds a little bit more confusion to that matter, but thanks for the heads up. Having learnt something new today.

I get this from here: http://physics.nist.gov/cuu/Units/binary.html
 
I think System Profiler is just reading the Win partition as used space. 32+27 does equal 59.

Spinnerly's math is also right. I was wondering about why 1K=1024 bytes a while back and looked up binary math. I don't really recall, but the extra comes from what happens when you raise a binary number by a power.

Dale
 
The "bi" prefixes were defined by the IEC.

I have seen at least one GUI Mac program that displays KiB, MiB, etc. I don't remember which.
 
The question comes up often and is listed in the MR Guides

Hard Drive Size Discrepancy

Hard Drive Size Discrepancy

Why does my new 500 GB hard drive report it only has 465 GB? Have I been ripped off?

No, you haven't been ripped off. 500 GB = 465 GB, strange as it seems.

The reason is that computers count a "kilo" something as 1024 (binary 2^10) while the rest of the world count a "kilo" as 1000 (decimal 10^3). A 'mega' in computer binary system is 1024 x 1024 = 1,048,576 (rather than decimal 1,000,000), and a 'giga' is 1024 x 1024 x 1024 = 1,073,741,824 rather than decimal 1,000,000,000

This creates a discrepancy of approximately 7% between the number of GB the computer reports, and what is advertised as the drive's capacity in GB. It is important to note that there is no difference in the number of actual bytes of storage - it is only a difference in reporting when the binary 'giga' terminology is used.

A 500 GB hard drive has about 500,000,000,000 bytes (it is never exact, commonly a drive is designed to have more bytes, to allow for a certain number of defective sectors to be mapped out). When counted on the computer, 500 Gb (decimal) = 500 billion bytes = 465.66 GB (binary).

Some propose using a different term, gibibyte (GiB) for the binary figure, however that is unlikely to catch on in the marketplace.


Woof, Woof - Dawg
pawprint.gif
 
Ok, I'm still confused.

So my starting size is 232 gb of usable space.

50 gb for the 'Untitled' partition
182 gb for the 'Macintosh HD' partition
=
232 gb

ok, so WHY is the 27 gb in the windows partition showing up as USED space on my Mac HD?? So the extra 27 gigs of space missing on my mac HD (which corresponds to the 27 gb in windows...) somehow is exactly the space I lose by formatting the hd? Don't I have a 250gig hd that gets formatted to 232...
 
Ok, I'm still confused.

So my starting size is 232 gb of usable space.

50 gb for the 'Untitled' partition
182 gb for the 'Macintosh HD' partition
=
232 gb

ok, so WHY is the 27 gb in the windows partition showing up as USED space on my Mac HD?? So the extra 27 gigs of space missing on my mac HD (which corresponds to the 27 gb in windows...) somehow is exactly the space I lose by formatting the hd? Don't I have a 250gig hd that gets formatted to 232...

I'm not sure this argument in this thread helps either.

Ok I have looked over your pics and your thoughts, and I think I see what you are saying. But where are you showing that your Mac partition is really only using 32GB. Do you show that in the pics anywhere, cause if you did I overlooked it.

Woof, Woof - Dawg
pawprint.gif
 
Ok I have looked over your pics and your thoughts, and I think I see what you are saying. But where are you showing that your Mac partition is really only using 32GB. Do you show that in the pics anywhere, cause if you did I overlooked it.

Woof, Woof - Dawg
pawprint.gif
On the second picture on the top of the window, if I'm correct. It says "32.3 on disk."
 
On the second picture on the top of the window, if I'm correct. It says "32.3 on disk."
Correct, I should have explained but the second picture is using WhatSize to figure out folder sizes...

I realized something was wrong when it was telling me my mac osx + some programs took up 59 gb while vista and those programs only took 27gb 😱
 
Correct, I should have explained but the second picture is using WhatSize to figure out folder sizes...

I realized something was wrong when it was telling me my mac osx + some programs took up 59 gb while vista and those programs only took 27gb 😱

Try using Grand Perspective
It will give you a graphical representation of where your usage is

See if that clears things up and repost

Woof, Woof - Dawg
pawprint.gif
 
I've downloaded a few things since the first pictures but not more than 1.5 gb or so.



Here's GrandPerspective. Says 31.9GB

gsudlv0g62dam25q3u.png
 
What do you get when you select the Macintosh HD and "get info"?
What does it say your capacity, free and used are?

Woof, Woof - Dawg
pawprint.gif
 
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