HDD Space Consumption Mystery

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This one is got me stumped.

I have two identical drives (Seagate 4TB), with the exact same stuff, amount of data. The mystery, is that there is approx 1GB in the different. One seems to have more. I've checked it thouroughly, to make sure that I don't have one identical file that is biggle than the other. All files are the same size.

Once I narrow down the the folders, the see which is differnet, it was my movies folder, one of my movies, was acting as a shortcut. It was Donnie Darko. WHen I opened it, it opened as a picture, that wa somewhere's else on the drive. So, I delete it, and copy it over form the other drive. I couldn't delete that file. I eventually did, but there is still space difference. It either goes from .6GB to 1.3GB.

I even formatted one of the drives and copied all the contents over to the other. Bascially, it was a 2nd backup, so I didn't lose anything. I don't understand what is going on.

I'm using Linux: Ubuntu 12.04 (64-Bit). When I've tested the drives, that was last fall. I'll do it again, sometime tomorrow or the next day, when I get around to it.

Are the drives formatted using different formatting standards? I noticed that the same files on a FAT32 volume take up a lot more space than on an NTFS volume. I don't know about Linux formats... I'm actually in the process of formatting a USB drive at the very moment under Kubuntu with Linux3. Ten hours elapsed, another ten hours to go!

Part of the problem has to do with how drive manufacturers specify storage capacity. The drive manufacturers specify a kilobyte as 1000 bytes, where OS publishers will specify a kilobyte as 1024 bytes.

As for files taking up space on a drive, anyone who's been in the business for any length of time will tell you FAT file systems were notoriously inefficient. Drive formatting by an OS utility I'll leave someone else to explain the intricacies of how it's done, and why it's done that way.

I know, I'm a programmer. I find it quite annoying that manufacturers use 1000 bytes as a KB and 1,000,000 bytes as a megabyte and so on as a marketing ploy. I recently downloaded a file that was just shy of 1 GB and wanted to put it only a 1 GB USB stick... no, too small. had to use my 8 GB stick instead.

As others mentioned, it could be the drives are formatted in Fat34/NTFS..

...or you could be looking at one drive (the one with the OS installed) using 1gb to create a mirror image backup of the operating system for recovery purposes.

It could also be you have an automated backup system active.

You could be using a program that is not flushing its TEMP file folder or swap folder (WinAmp used to do this long ago)

Both are formatted to NTFS on GUID Partition Table.

Are you running a PC or a Mac? PC normally don't use GUID. I know windows 7 can format GUID if and only if that PC uses EFI instead of ROM-BIOS. Unfortunately, Microsoft, as usual has a screwed up implementation of GUID and EFI.

How much RAM is installed on this machine? It could be the disappearing hard drive space is due to a swap file.

Linux: Ubuntu 12,04 (64-Bit).

I've just checked both drives again, and made sure they were equally backed up, and it says they have and use equal amount of space. I am also using a different computer than before. It couldn've been a fault with the OS, or maybe the computer?

Before, it was on the the 2nd office computer (which has been upgraded since than).
It had:
Motherboard: ASUS P5G41-M LX (750 socket)
Processor: Intel Core 2 @2.60GHz x2
RAM: 2x2GB DDR2 @800MHz
HDD 1: Western Digital (Caviar Black)1TB (64MB Cache/7200 RPM, connected via SATA (Windows 7: Ultimate)
HDD 2: 720p GB HDD (Seagate?) (N/A) I don't think I have it anymore. (Ubuntu 12.04)
LInksys WiFI PCI card
I don't know if this is relevent, but it also has Windows 7: Ultimate on another HDD. 750GB HDD conected via SATA.

The other office computer has not been upgraded yet, and still has identical hardware, except there i no WiFI

I'm using my desktop computer, that I built a few months ago.
OS: Linux: Ubuntu 12.04 (64-Bit)
Motherboard: ASUS Z87-K
Processor: Intel Core i5-4670K @3.40GHz x4
RAM: Kinston 8x1GB DDR3 @1600MHz
HHD: Wetsern Digital (Caviar Green) 2TB (64MB Cache/7200 RPM) connected via SATA

Could it perhaps be because of indexed restore points? Also, A lot of windows computers from about 2K8 or so have a hidden restore partition that allows you to restore a computer that has been bodged up,, instead of shipping with recovery media. This couls also explain the 1GB discrepancy between drives.