Hard Drive Space Discrepancies

So, the actual usable space of my VAIO hard drive is 288 GB. And it reads as having only 2.13 GB available.

However, all of my personal files (in the folders such as Downloads, My Documents, My Music, My Pictures, and My Videos) only takes up 233.45 GB.

So what is taking up the other 52.42 GB? And how do I eliminate it?

EDIT: My VAIO is an EE-31FX, running Windows 7 64-Bit.

 

288 GB as reported by? the computer? the manufacturer? who?

 

Several reasons:

1: The NTFS default block size is 4 kB. This means that any data you write will be rounded up to the nearest 4 kB. A 5 kB and a 7 kB file will both use 8 kB of disk space, because that's the nearest number of blocks that can hold all the data. On average, you lose 2 kB per file. If you have a lot of files, this can be significant.

2: Metadata. It's not only the data of a file that gets recorded, but also so-called metadata, which includes the file name, ownership, permissions, and a list of which blocks the file occupies. For really large files, the list of blocks can be substantial, and you use several blocks extra just to record this.

3: Restore points. Before you install anything, Windows will usually create a restore point, which means it keeps copies of what you had on your drive so you can go back. By default, up to 10% (I believe) of your drive space can be taken up for this.

4: Disk journals and file system metadata. NTFS is "self-repairing", in that writes go to a journal before being committed to "real" space on a disk. If your machine crashes or you reset it, the journal is replayed and only complete actions are committed. That prevents having half-written or (even worse) half-deleted files. In addition, there's other file system metadata, including bad block mapping, and a copy of the superblock and file table (if one goes bad, it will use the other).

5: Different measurements. The OS counts 1 kB = 1024 B, 1 MB = 1024*1024 B, 1 GB = 1024^3 B and 1 TB = 1024^4 B.
Hard drive manufacturers, on the other hand, use 1000 as the base for consumer drives, because that makes a bigger number. A drive that's 466 GB (1024^3) can be sold as 500 GB (1000^3), and a consumer would typically buy a drive labeled 500 GB over one labeled 466 GB at the same price, not noticing that the capacity is the same.
I say consumer drives, because no matter what HD manufacturers want you to think, this isn't how they've always done things. Their enterprise drives are measured in powers-of-two, and what is sold as an 80 GB drive to consumers is sold as a 73 GB drive to professionals (who need to be able to match drive sizes exactly for RAID, among other things).

6: SSD creep. For SSDs, a portion of the drive is set aside for bad block mapping, wear leveling and to assist with pre-erasing sectors. This too is nothing new - a SCSI HDD, for example, will have a good sized chunk for bad block mapping. The difference is that with SSDs, some manufacturer now count that unusable space too, to get an even bigger number; because SSDs are so much smaller to start with, every bump counts.

So you may find that a 256 GB drive may really only have 238 GB usable space, and that's base-10 GB, so in base 2 GB which the OS uses, it's 221 GB. Then you format it with a file system (like NTFS) and may be down to 210 GB. And that doesn't mean you can store 210 GB of data on it either, but depending on the number of files you have, perhaps 190 GB. Less if you install and uninstall programs, and have restore points.

Yes, you're expected to know these things. It's like knowing that a car sold as 33 mpg doesn't mean you can tank up 10 gallons and expect to guaranteed be able to drive 330 miles.

 

^^ AWESOME POST!

the 4kb block is not only used on NTFS, and if I remember correctly it was sommething that IBM made up some 25 years ago or more

 

Try to use this tool called Spacesniffer:

SpaceSniffer, find lost disk space the easy way.

I've been wondering where did I lose my disk space but then I found this application. This application gives a very clear tree diagram (well technically not a tree but a box rather) of how your disk space is taken up. It's very specific and you can look into folders to find out what's in there. Go try it out

 

Did you uncheck the option to 'hide protected operating system files' in folder options?

 

Different file systems have different block sizes, which can often be adjusted at format time. NTFS, for example, has 4 kB as default, but can be set to anything from 512 bytes up to (IIRC) 64 kB blocks. The larger the blocks, the faster sustained transfers, and less fragmentation, but also the more waste, and slightly less efficient disk caching.
If running a file server with lots of RAM, it's fairly common to bump up the file system block size to gain extra performance.