Saturday, March 21, 2009

Hard Drive Size

Hard drive space:
To those of my friends who ask me about this EVERYTIME they get a new system.
"Why is my hard drive capacity not what is says on the box?"
I've got to say.
"What in the hell are you looking at this for, or more importantly CARING about this. Man you gotta focus on more important stuff."

The way hdd space is reported by different hardware and software can be very misleading.For instance my 1TB Maxtor external hdd reports in Windows 2003 Enterprise Server as 931 GB in Windows Explorer, however if I right click and check the properties on it, it shows a capacity of 1,000,202,240,000 bytes or in technical terms just over 1 Terabyte.
Here is a really good explanation:
Example:
"I have a 120 GB hard drive but Windows XP claims it's size is 111.8 GB. What has happened to the other 8.2 GB? "
Here is the definitive answer:

Hard drive manufacturers calculate hard disk size in 'base 10' notation while Windows does the calculation in 'base 2' (binary) format.
Both the manufacturer and Windows are giving you the "correct" number.
1 Gigabyte as defined by a manufacturer is 1,000,000,000,000 Bytes. This makes sense in the metric base 10 sense as we define kilo as 1000, mega as 1,000,000 and giga as 1,000,000,000,000.
Windows, however, calculates the disk size in a base 2 system. Base 2 does not convert into base 10 exactly in most cases but back in the day it was close enough so that a kilobyte was defined as 2^10 or 1024. 2^10 is 1024 is 1 kilobyte2^20 is 1048576 or 1 megabyte2^30 is 1073741824 or 1 gigabyte.

When the hard disk manufacturer sold you a 120 Gig hard drive, they were selling you 120,000,000,000 bytes.
Windows divides this number by what it considers a GB (1073741824) and reports the hard disk size as:120000000000 (bytes) / 1073741824 (bytes per GB) = 111.8 GB.
This accounts for the 'missing' 8.2 GB in the hard disk's size.
You still have 120,000,000,000 bytes to use but because of inconsistent definitions of what kilo, mega and giga really represent, there is an inconsistency in the measurement of size.

Get it??

Now do the math and you will see what you have.
End of story.
Have fun out there.

No comments:

Post a Comment