How does 120GB = 111.79GB?

Question

Level 1

0 points

How does 120GB = 111.79GB?

I just opened my spankin' new MBP and was looking around. I noticed on my "System Profiler" that the 120GB hard drive is actually only 111.79GB or 111.34 GB depending where I looked. What's up with that???

I paid an extra $90 for 20GBs... and got <12GB.

Here is what my system profiler says:

"TOSHIBA MK1234GSX:

Capacity: 111.79 GB

Macintosh HD:
Capacity: 111.34 GB
Available: 92.89 GB
Writable: Yes"

Has anyone noticed this?
Am I missing something?

MBP 2GHZ 120GB, Mac OS X (10.4.5)

Posted on Mar 15, 2006 6:02 PM

Reply

Answer 1

Mar 15, 2006 6:08 PM in response to EndoSkate

every hdd ive ever had does that, alot of space is used up from the start because of things like the OS and all the programs installed on it

Reply

Answer 2

Bartok19

Level 1

60 points

Mar 15, 2006 6:13 PM in response to EndoSkate

Manufacturers use a GB to mean 1,000,000,000 btyes. The computer considers a GB to be 1,073,741,821 bytes. 120 GB as advertised by manufacturer is recognized by the computer as 111.79 GB.

Reply

Answer 3

EndoSkate Author

Level 1

0 points

Mar 15, 2006 6:17 PM in response to megamaccer

I understand that the hard drive has OS and other software installed, but the "available space" on my HD started out to be 94GB. The "System profiler" shows both capacity and usable space.

currently:
"Macintosh HD:
Capacity: 111.34 GB
Available: 94.25 GB"

So am I to understand that 120GB minus space from OS equals 111.34... minus bundled software equals 94.25?

Reply

Answer 4

Mar 15, 2006 6:21 PM in response to Bartok19

Manufacturers use a GB to mean 1,000,000,000 btyes.
The computer considers a GB to be 1,073,741,821
bytes. 120 GB as advertised by manufacturer is
recognized by the computer as 111.79 GB.

Bartok is absolutely right. Marketing strikes again.

Reply

Answer 5

Bartok19

Level 1

60 points

Mar 15, 2006 6:23 PM in response to EndoSkate

See below. You started out with 111.79 GB (120 GB using computer manufacturer's definition of a GB) and are now left with 94.25 GB (101.2 GB using computer manufacturer's definition of a GB) after the OS and bundled software have been installed.

Reply

Answer 6

EndoSkate Author

Level 1

0 points

Mar 15, 2006 6:25 PM in response to Bartok19

Thanks Bartok

Reply

Answer 7

Mar 15, 2006 7:18 PM in response to EndoSkate

Computers use base 2 to count (binary), humans use base 10. Marketing chooses whichever one makes them look better 🙂

1GB = 2^30 bytes (actual)
1GB = 10^9 bytes (marketing)

Reply