Solved

Hard Drive Size on the box vs actual: are there different measuring conventions?

Posted on 2004-08-20
4
762 Views
Last Modified: 2013-11-15
On my new HD box it says 1GB = 1 billion bytes.  I thought there were 1024k in a kb, 1024kb in a mb, and 1024 mb in a gb.  So a gb should be 1,073,741,824 bytes not 1,000,000,000.  Which is right?  Are there two ways of measuring the same thing?  Maybe this explains why my 250gb HD only shows as 243gb capacity in disk management.  Wonder why they are allowed to exaggerate the size so much;  7gb is quite a significant amount of "rounding".
0
Comment
Question by:mark876543
4 Comments
 
LVL 32

Assisted Solution

by:Luc Franken
Luc Franken earned 50 total points
ID: 11851338
Hi mark876543,

You're right, a read GB is 1,073,741,824 bytes, but harddisk manufactors always advertize with a GB being 1,000,000,000 bytes.
So in this case, you bought a 250GB disk, which is in fact only a 243GB disk.

Greetings,

LucF
0
 
LVL 69

Assisted Solution

by:Callandor
Callandor earned 50 total points
ID: 11851362
> why they are allowed to exaggerate the size so much

Because advertising is all about stretching the truth!
0
 
LVL 11

Accepted Solution

by:
DoTheDEW335 earned 200 total points
ID: 11851587
found the perfect explaination:

First, Windows detects drive space as a power of 2 function. So, to Windows, 1KB = 2^10 (2 to the power of 10) = 1,024 bytes.

Then:

1MB = 2^20 = 1,048,576 bytes
1GB = 2^30 = 1,073,741,824 bytes
1TB = 2^40 = 1,099,511,627,776 bytes

etc.....

However, this makes drive look a little small in Windows. Hard drive manufacturers don't like that. They want the biggest number on the box as possible. So, they use the conventional base-10 method of counting. To them, 1KB = 1,000 bytes.

Then:

1MB = 1,000,000 bytes
1GB = 1,000,000,000 bytes
1TB = 1,000,000,000,000 bytes

Now let's do some math. Your hard drive says it has 120GB. It's detected as having exactly 120,023,252,992 bytes. Now, that's base-10. Let's convert it.

120,023,252,992 / (divided by) 1,073,741,824 (Window's # for 1GB).

We get a nice round 111.78GB.

The second drive is 122,904,969,216 / 1,073,741,824, and we get 114.464GB

Source:
http://computing.net/windowsxp/wwwboard/forum/89813.html
0
 
LVL 15

Assisted Solution

by:adamdrayer
adamdrayer earned 200 total points
ID: 11852157

Our brains are so used to the decimal system that 1024 is the easiest and closest we can get to 1000 by using binary.  

According to the actual definition stretching back to the metric system, A Kilobyte should equal 1000 bytes.  In computers, it's more effecient to let this equal 1024.  Otherwise we'd be wasting space.

In that sense 250 Gigabytes litteraly means 250 billion bytes, but computers count Gigabytes in increments of 1024, instead of 1000.
0

Featured Post

Courses: Start Training Online With Pros, Today

Brush up on the basics or master the advanced techniques required to earn essential industry certifications, with Courses. Enroll in a course and start learning today. Training topics range from Android App Dev to the Xen Virtualization Platform.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

In the modern office, employees tend to move around the workplace a lot more freely. Conferences, collaborative groups, flexible seating and working from home require a new level of mobility. Technology has not only changed the behavior and the expe…
This guide will walk you through the essential considerations and tech stack for building scalable websites. Know how to grow your business the smart way!
This video will demonstrate how to find the puppet warp tool from the edit menu and where to put the points to edit.
The viewer will learn how to successfully download and install the SARDU utility on Windows 8, without downloading adware.

816 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

10 Experts available now in Live!

Get 1:1 Help Now