Change the way your files are stored on a computer's hard disk

Filing systems play an important role in ensuring Windows and programs that run within the operating system can quickly access files stored on the hard disk.

There are two main types of filing system used by Windows: Fat 32 and NTFS and, while both do the job, there are important differences between them.

In this guide we will talk about both and look at the circumstances where you might need to make the switch from one to the other.

Hard disks organisation
Like any good library, your PC’s hard disk has to organise stored information so it can be found easily. So, rather than just chucking everything into a great long alphabetical list (think how difficult it would be to navigate around a Windows folder with millions of Word documents in it) the position of each file on the disk is kept in a table – a bit like a table of contents in a book, or a set of index cards in a library.

In fact, files are stored in individual ‘sectors’ on a hard disk and, in turn, these are organised into ‘clusters’. It is these clusters that are stored in the table. 

The point of this is so that when Windows or a program needs to find a file they can look in the table, rather than having to rummage through the entire disk, which makes finding files faster.

There are two main types of filing system used by PCs: Fat 32 and NTFS. Fat 32 stands for File Allocation Table (32 refers to the number of bits it uses to identify each cluster on the hard disk – older versions used Fat 12 and Fat 16) and NTFS is short for New Technology File System, a more modern way to organise a hard disk introduced with the Windows NT operating system.

What’s the difference?
Broadly speaking, Fat 32 works better on older PCs with smaller hard disks, while NTFS works better on newer PCs with larger ones.

Fat 32 has some annoying limitations. For example, it doesn’t understand files larger than 4GB. This was fine when it was introduced many years ago but useless for handling modern video files, which can be much larger.

In addition, Microsoft inserted a limitation that stops XP, Vista and Windows 7 from creating disk partitions larger than 32GB on a Fat 32 system – though this doesn’t stop Windows from reading and writing to Fat 32 disks larger than 32GB.

But the newer NTFS removes these restrictions. It finds files more quickly because it doesn’t need to access the disk as many times and it keeps a log of what it’s doing, so if something goes wrong while writing to the disk it can find the necessary undo and redo information to sort things out.

NTFS also uses disk space more efficiently and, depending on the version of Windows, allows data to be encrypted or compressed to save disk space.

Which one does my PC use?
Most modern PCs will come with disks pre-installed with Windows and pre-formatted using NTFS. In general, users of Vista and Windows 7 will have NTFS, but XP users may have either Fat 32 or NTFS.

If you have bought an external hard disk for backing up you may discover that it’s been formatted using Fat 32 as well, in which case you should consider changing it.

It is possible to easily change from one filing system to the other. For example, Fat 32 disks can be safely converted to NTFS and any files stored on them will be converted as well.

However, while NTFS disks can be converted to Fat 32, this requires a reformat that will destroy any data stored on the disk. See the walkthrough below for more help.

Finding out what filing system your disk uses is easy. Double-click on the My Computer icon on the Desktop. When the window opens, right-click on the disk you want to check and choose Properties.

When the dialogue box appears, ensure the General tab is selected at the top and have a look for the ‘File system’ label – it will say either Fat 32 or NTFS. Click the OK button to close the dialogue box.

Security enhanced
Most of the time with a modern PC you can just stick with whatever filing system the PC has. However, with older computers or some external disk drives, it’s extremely useful to know which kind you have got so you can consider converting a disk from the older Fat 32 system to NTFS. 

This means you can take advantage of larger file sizes and partitions as well as the enhanced stability and security.

Convert a Fat 32 hard disk itno NTFS with Windows 7

1 First, perform a full backup. Now make sure you know the letter label of the disk you are converting (ours is drive G:). Click the Start button, type cmd into the search box and press Enter.

2 When the command window opens, type convert drive letter: /fs:ntfs, with the spaces. We are converting drive G: so we will type convert g: /fs:ntfs and then press Enter.

3 Type in the name of the drive when asked (Windows calls this the volume label) – ours is WIN BACKUP – and press Enter. Windows does its stuff and then reports back – conversion complete. Then open the Properties dialogue box to show the ‘new’ NTFS disk.