[zacharie]

Hello,
I have just received my new Powerbook Ti 1 ghz with 60 gb HD.
However I have noticed a curious thing:
When i use disk utility and information about my hd, details give
Capacity 55.89 GB (60,011,277312 Bytes)

Please, could someone explain me where the 5 gigs difference went by?

thank you.
zacharie

[dettociao]

That's the correct "60gb" capacity. Because of the nuances of 1024bytes > 1k > 1024k > 1mb > 1024mb > 1gb, it works out so that 55.x gb is the actual formatted capacity of a 60gb drive.

Correct me if I'm off somewhere in there-- I know someone will.

[The Placid Casual]

Originally posted by dettociao:
That's the correct "60gb" capacity. Because of the nuances of 1024bytes > 1k > 1024k > 1mb > 1024mb > 1gb, it works out so that 55.x gb is the actual formatted capacity of a 60gb drive.

Correct me if I'm off somewhere in there-- I know someone will.

Spot on

On the box of all Apple products, there is always, somewhere near the HD decription, a phrase a bit like this:

"Unformatted Size. Formatted size will be smaller."

Peace,

Marc

[Karim]

Kind of like a cheeseburger, 1/4lb before cooking, shrinks after.

[videian28]

lol

[Moose]

Heh. Partly formatting, but mostly marketing.

Your drive is 60,011,277,312 bytes. Hard drive manufacturers market capacity in powers of 10. Their gigabytes are 10^9, or 1,000,000,000 bytes. Using this metric, the hard drive is 60.01GB. The OS, however, uses powers of two, representing a gigabyte as 2^30, or 1,073,741,824 bytes. Using this metric, the hard drive is 55.89GB.

Technically, the hard drive manufacturers are using the correct unit. The SI prefix "giga" means 10^9. The SI prefix "gibi" means 2^30.

More information.

[dettociao]

Originally posted by Moose:
Heh. Partly formatting, but mostly marketing.

Your drive is 60,011,277,312 bytes. Hard drive manufacturers market capacity in powers of 10. Their gigabytes are 10^9, or 1,000,000,000 bytes. Using this metric, the hard drive is 60.01GB. The OS, however, uses powers of two, representing a gigabyte as 2^30, or 1,073,741,824 bytes. Using this metric, the hard drive is 55.89GB.

Technically, the hard drive manufacturers are using the correct unit. The SI prefix "giga" means 10^9. The SI prefix "gigi" means 2^30.

More information.

Damn. See? I told you someone knew a hell of a lot more about it than I do. Thanks for the link Moose, that's pretty interesting.

[spaced]

Originally posted by Karim:
Kind of like a cheeseburger, 1/4lb before cooking, shrinks after.

Best... metaphor... ever.

[zacharie]

Originally posted by spaced:
Best... metaphor... ever.

Now I understand why I am always hungry. Thanks for the info.

[Eug]

Originally posted by spaced:
Best... metaphor... ever.

Well, it's funny but not accurate really. See Moose's post above.

BTW zacharie, if you got a SuperDrive, soon you'll be wondering why your DVD-Rs don't hold 4.7 GB. If so, then think back to this thread.

[Moose]

Originally posted by spaced:
Best... metaphor... ever.

But not really applicable. The loss of space due to formatting is very minimal. Certainly much, much less than 4.12GB.

His hard drive is 60.01 gigabytes, which is the same thing as 55.89 gibibytes.

[zacharie]

it's good to learn...

[Luca Rescigno]

60 billion bytes * (1 kilobyte/1024 bytes) = 58.59 million kilobytes

58.59 million kilobytes * (1 megabyte/1024 kilobytes) = 57220 megabytes

57220 megabytes * (1 gigabyte/1024 megabytes) = 55.89 gigabytes

Take the number of bytes, and divide by 1024 three times. That is how many formatted gigabytes you get.

[iDaver]

Hmmm, thank you Luca. So it's not false advertising after all. I always thought HD size description was similar to the old 15", 17", etc. monitor falsehood which eventually resulted in every advertisement for CRT monitors also stating the "viewable" size. Now I know better.

[dettociao]

Originally posted by iDaver:
Hmmm, thank you Luca. So it's not false advertising after all. I always thought HD size description was similar to the old 15", 17", etc. monitor falsehood which eventually resulted in every advertisement for CRT monitors also stating the "viewable" size. Now I know better.

It sort of IS like that! It's an "advertised size" and a "usable size".

[Moose]

Originally posted by dettociao:
It sort of IS like that! It's an "advertised size" and a "usable size".

No. It's not like that at all. What the hard drive manufacturers is saying is 100% accurate. You get to use almost all the bytes on the drive for actual storage (not all, the filesystem structures take some space, but nowhere near 4GB).

This is closer to equating a yard and a meter to be the same thing. While they're roughly the same, if you express 63360 inches as yards and meters, you're going to come up with 1760 yards, and 1609 meters. It's the same distance, but, and this is the important thing that you're not getting:

THE HARD DRIVE MANUFACTURERS AND THE OPERATING SYSTEM ARE USING TWO DIFFERENT DEFINITIONS FOR GIGABYTE. The hard drive manufacturers define a gigabyte to be 10^9 bytes, and are correct. The OS is using the "old-style" definition of 2^30, and is incorrect.

Read above for an article defining gigabyte and gibibyte.