80gb drive shows up as 76

[l3ored]

see title.

 

[Gurck]

Formatting takes up some space.

 

[EeyoreX]

Formatting takes up some space.

Not really. Formatted capacity is different than the capacity listed on the box. This is due to two different ways of measuring hard drive sizes. Most (all?) OSes use a binary system, where 1GB = 1,073,741,824 bytes, while hard drive manufacturers use a decimal system, making 1GB = 1,000,000,000 bytes. This is completely normal, so nothing "gives". This has been discussed before, a search would have been a good plan. And a further answer/explaination, as well as a handy chart can be found here.

\Dan

 

[Mik3y]

its because of the ways the makers calculate the size

 

[n7]

Not that much.
There are two different types of space measurement: decimal & binary.
Hard drives are advertised in decimal; Windows shows them in binary.
There is a conversion tool somewhere, i'll try to find a link to it.
Someone else can can likely better explain this than i can.

 

[Paulson]

All the 80 GB drives I've had show up as 74.6 GB in windows... so where did you get 76...

 

[batmanuel]

There's also a difference in how the hard drive manufacturers measure hard drive space and Windows.

The manufacturer calls 1,000,000 bytes a MB, but for the operating system there are 1,048,576 bytes in a MB since it is using binary and not decimal unit if measurement. If you divide the the former by the later, you see that the binary method of measuring only gives you 95% of the size of the decimal method. And 95% of 80GB is 76GB, which is exactly what you're seeing.

Now mind you, they really aren't lying so much as fudging the math. Ususally you'll see a disclaimer in very small print on the package or on Dell's website (for example) that states that 1GB is equal to a million bytes, so they don't get sued for lying about the size - although at leaste one person has actually filed one suit despite the disclaimers.

Gotta love those advertising departments.

EDIT: Just realized I did my math wrong, did my calculations using MB instead of GB. I've edited my response to change GB to MB, but after redoing my math I realized that at the GB level the binary method is 93% smaller than the decimal method, and an 80GB drive actually comes out to around 74GB, so I'm kinda confused now as well.

 

[batmanuel]

Originally posted by: Paulson
All the 80 GB drives I've had show up as 74.6 GB in windows... so where did you get 76...

That's probably the drive formatting taking a little chunk of the drive size, in addition to the binary/decimal thing. l3ored didn't get into the details, but he may have been looking at the drive size that the Windows installer or the disk managment utility detected prior to formatting the drive.

 

[l3ored]

Originally posted by: Paulson
All the 80 GB drives I've had show up as 74.6 GB in windows... so where did you get 76...

right click on c:/ in my computer and go to properties, mine says 76.6 gigs


thanks batmanual, do you know if theres anything else that calculates 1g as being 1,000,000bytes, or is it just hard drive manufacturers? and what about the raptors, how are those calculated?

 

[LTC8K6]

My WD120JB drive's properties:

120,031,477,760bytes 111GB

 

[l3ored]

Originally posted by: l3ored

Originally posted by: Paulson
All the 80 GB drives I've had show up as 74.6 GB in windows... so where did you get 76...

right click on c:/ in my computer and go to properties, mine says 76.6 gigs (hitatchi deskstar)


thanks batmanual, do you know if theres anything else that calculates 1g as being 1,000,000bytes, or is it just hard drive manufacturers? and what about the raptors, how are those calculated?

 

[MDE]

Originally posted by: l3ored

Originally posted by: Paulson
All the 80 GB drives I've had show up as 74.6 GB in windows... so where did you get 76...

right click on c:/ in my computer and go to properties, mine says 76.6 gigs


thanks batmanual, do you know if theres anything else that calculates 1g as being 1,000,000bytes, or is it just hard drive manufacturers? and what about the raptors, how are those calculated?

The Raptors are calculated the same way. Is your 80GB drive a Maxtor? My 80GB Maxtor shows up as 81 on the system info screen (just before Windows boots) and Windows says it's 76GB.

 

[EeyoreX]

Every hard drive, Raptors included, is calculated the same way. The manufacturers are not likely going to change, because marketting, for example, a 186GB drive does not sound as good as marketting a 200GB drive. The OS makers are not going to change either. It would not be to Western Digital's advantage to label all their hard drives using a decimal system except the Raptors. Read the box of whatever hard drive you are going to buy. Most, if not all, list a formatted capacity which is what the computer will show the drive as vs what the box says. The chart I provided a link to in my earlier post will list these values. However, it is odd that Western Digital (whos site I linked to for that chart) does not currently list the Raptor drives. However, you can do the math and figure out the formatted size.

\Dan