free space discrepency on hard drive in winxp pro

[Jaylio]

When I right click on C: drive in my computer and select properties, I get how much used space and how much free space. However, my question is why is there a difference in the first set of numbers and the second set ??? These are the numbers I get.


Used space: 20,934,811,648 bytes 19.4GB
Free space: 61,013,311,541 bytes 56.8GB


Capacity 81,948,541,254 76.3GB


Can anyone account for these differences?? I have defragged and I am using winxp pro. I am losing over 4 gigs of free space

 

[Cogman]

first off this is a highly technical forum, not a tech support forum. Second, im guessing you bought a 80 gig HD and you think it is missing 4gb and reading 76 right? well it is all about standards here. in computer land one megabyte is equal to 1004 bytes, but in industry land one megabyte is equal to 1000 bytes. with the smaller hard drives it makes little diffrence, but when you get into the higher numbers, you start to see gigs of diffrence. again this is not tech support, this is highly technical, where we discuss the meaning of life or the future of alien civilizations.

 

[uart]

I am losing over 4 gigs of free space

Actually there is no lost space, this is just a reporting anomally. Actually it really isn't even so much an anomally as a case of simple conflicting definitions of kB, MB and GB.

The conflict arises from the multiple conflicting definitions of "k" in relation to computer storage quantities. The SI (standard international) definite of "k" is 1000, but for convenience with regard to base 2 arithmetic the computer industry effectively re-difined it as "k" = 1024 when relating to computer storage quantites. (note that 1024 = 2^10, making it far more convenient for base 2 arithmetic than the "true" 1000).

The SI prefixes of M and G were similarly corrupted to mean "1024*1024" and "1024*1024*1024" respectively.

Now HD manufactueres are under no obligation to use the "corrupted" definitions and are quite free to use the standard definitions of k, M and G in there specified/advertised capacities. Thus we have the situation where 1000,000,000 Bytes is equal to 1GB if one takes the SI definition of "G" but a mere 1/1.024^3 = 0.93 GB if you use the computer nerd definition of "G". This is precisely where your apparent lost capacity is rooted.

In particular 81.95/1.024/1.024/1.024 = 76.32, in exact accordance with your quoted figures.

Other comparisions that may be useful to you are :

80,000,000,000 B = 80,000,000 kB = 80,000 MB = 80 GB, if one uses the SI standard defn of k, M and G.


If however one uses the "computer" definition of k, M nd G the above equality becomes
80,000,000,000 B = 78,125,000 kB = 76,294 MB = 74.5 GB

 

[sao123]

:|
Plz read and follow the guidelines for this forum.

Questions regarding troubleshooting, technical support, and product advice belong in other appropriate forums such as General Hardware, Networking, Video, etc. They have more traffic and, they are visited by knowledgable, enthusiastic members eager to share good advice and help troubleshoot problems.

off-topic posts are likely to be moved or locked.

and

(but don't rely on it to do your homework)

 

[Jaylio]

thanks uart!!!! That explains it perfectly. Maybe I am not as smart as some of you other anandtechers but with uarts explanation of hard drive space, I think this question is "highly technical".

 

[sao123]

I suppose "highly technical" depends on your point of view...

From mine...
if your asking a question pertaining to your computer... that is advice, technical support, etc...its not highly technical just because you dont understand it.

if your starting a discussion or debate about hard drives in general and why they report GB in Base 10 vs Base 2.
Technology in general, that's more suitable for the highly technical forum.