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Help ?!? HDD used space vs. size of files in disk

Last response: in Storage
August 19, 2008 4:01:36 PM

First time posting here, apologies if not in right section of forums.

I have a recent new build, and every thing is working great. My only issue is that the used space and size of the files on my boot drive don't jibe, as in the screen captures below:

The right hand capture is with all files on C:\ selected, I did not include the hidden files, but did not think that the would be 100 GB worth of hidden files.

Any suggestions as to why this is, or what I may do about it are greatly appreciated.

August 19, 2008 7:07:40 PM

Fix the picture :p 

Also list what size hard drive you have and what OS you are using.
a c 353 G Storage
August 19, 2008 7:52:00 PM

Answer, cluster size vs sector per cluster.

A file will use a full cluster(s) even when smaller.

ie sector = 512 Bytes and cluster = 4 sectors then cluster = 2K. if you write a 1 K file, it will occupy 2 K disk space. if you write a 1/2 K file it still used 2K. If you write a 5 K file it will take 6K.

(Sector/cluster size just for explanation) need to check your HDD for cluster size.
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August 19, 2008 9:35:54 PM

rozar Fix the picture :p 

Also list what size hard drive you have and what OS you are using.

Thank you for your reply.

The drive is a WD Velociraptor 300 GB

Using Windows Vista Ultimate x64.

What is wrong with the picture? (not being sarcastic here)

August 19, 2008 9:44:04 PM

For me the picture does not show. I managed to copy and paste the link and that worked. You show 279GB for the raptor which is correct with decimal to binary conversion. Then you show roughly 139GB on both free space and used space. I am not sure how you came up with the total of files on the right. Did you unhide all files both system and not? There are alot of files that might not show up if you didnt. I dont think it would be 100GB of files but that might help you figure out what the problem was if you knew the exact size of the difference.
August 19, 2008 10:12:07 PM

Your picture shows 2 picts, however you did not actually chose all files of all types in C:\(as you are thinking). This is something I've always disliked about how Windows shows you the properties when multiple items are selected. It's quite confusing, and really not helpful to read the type/location in the properties window if you have more than 1 file and/or folder selected.

Yours says:
Type: Multiple Types
Location: All in C:\

I just grabbed 2 .doc files on my desktop(and there are more than 2 .doc on my desktop) and I get properties on them it says:

Type: All of type Microsoft Word Document
Location: All in C:\(etc).

Now, I did not have ALL of the .doc files selected in the location specified, nor did I select all of the files in that location. It just generalizes as best as it can and gives you that info. It really is worthless to look at those, except to verify that if you select 10 .doc files, that it doesnt say multiple types.

Now, what you certainly didn't do was select all hidden files. The hidden box and text is greyed out. If the box is grey filled then that means that at least 1 hidden file is selected. In this case it shows that all of the files you selected are read only(probably system files, and not that when I say files, I mean selected them, not in subfolders).
I don't use Vista, and never will, but in XP what you need to do is either go to C:\ and hit CTRL+A to select all files. If you do hot have hidden files displayed, it will probably ask if you want to select hidden files. Click yes and then get properties. The alternate way is to view all hidden/system files and folders, and then get properties.

In XP(and probably even more so in Vista) there are folders that you are not allowed to even view the contents of(one of them is something like c:\system volume information\). Users are not supposed to be looking inside that folder because those are supposed to be for system use only. This was done as a safety precaution so you could not open one of the files to view the contents(locking the file from other programs) and the OS try to write data to it. The OS relies on the fact that it will open those files and use them as it sees fit, and that nothing will ever stop that from happening.

I use a program called disk size manager to look at the folder sizes. It works really well. I don't remember how it handles hidden files, but I always view them anyway. It might give you insight as to what is taking up those 100GB

On another note, try running a chkdsk. That might find that the 100GB of space is marked as used, but is in fact not used. Running chkdsk might free up the space immediately.
August 20, 2008 12:58:03 AM

I see the problem with the pic, sorry about that. I guess I don't know how to post them correctly.