Fdisk and Format

Understanding and using Fdisk and Format utilities to prepare your hard drive for use

In previous articles we've built an imaginary scenario which helps to explain the complexities of the subject. This article is no exception!

Imagine you have a large empty room and a large number of books to store in it. If you put all your books in a huge pile in the centre of the room, you will have achieved the basic task of storing your books.

You now want to retrieve a specific book to read it. Your task is almost impossible. For the time it takes to search through the entire pile of books for your specific title, you could have read several others from cover to cover. Not Good.

Your next step might be to fill the room with shelves to hold the books, so that you can quickly scan the titles and locate the book you need. Not a great system, but for a reasonable number of books (say 100 or so) its faster than before and no big deal.

Assuming that you had a good deal more books than 100, you might develop various 'systems' to give you fast access to the book you're looking for. For example, you might divide your library into sections like 'Comedy', 'Law' or 'Fiction'. You might build an index of all your books and store information on each book, e.g. the section it is stored in and on which shelf. Within a few minutes of searching, you will most likely have found your desired book. Perfect.

OK, so what about Fdisk and Format?

The Hard Disk in your PC is its 'library'. When it wants to find information it goes to the Hard Disk and looks for the information it needs. In the same way that we prepared our 'room' to store our books, A Hard Disk must be prepared to store data.

Although this is mostly done as a part of the installation of an Operating System like Microsoft Windows, two programs are also available (although, somewhat hidden) to help a PC Owner configure their Hard Drives and other storage devices for special reasons. Let's take a closer look at each one...


The Fdisk program is the 'library builder'. It can create and manipulate 'partitions' on your Hard Disk. Usually, Fdisk is used to create one big partition using all the space on the hard disk - effectively like having the entire room as one giant library.

Additionally, Fdisk can be used to divide up the space on the Hard Disk. An example of this might be as follows:
In your 'library', you might have some very delicate books that are over 100 years old. You might choose to divide your room into two sections or 'partitions', one for recent books in good condition, and another for the older books.

As an extreme example, you might do this so that, in the event of a fire in the main part of the library, the older books will be afforded some protection, since they are stored in another 'room' of the library.

Getting back to PC's, you might like to create a separate partition on your Hard Disk to store all your important files in. Fdisk allows you to specify the size of each partition as part of the total capacity of your Hard Disk.


The Format program takes on the role of setting up the 'library' and its 'systems'. Each partition must be individually 'Formatted' before it can be used to store files.
In terms of our 'Library' scenario, Format will fill the room with shelves and setup a system so that new books can be quickly and easily added in future.

Depending on which version of Microsoft Windows you have, Format will be able to use a selection of systems:

Usually found on older system FAT16 might be used for small capacity Hard Disks Up to 2GB. In fact, FAT16 is only able to format to a maximum of 2GB
The most common system in use today as it can handle a far greater size of Hard Disk
A newer system, previously only used on Servers and high-end systems is now offered in to the home user in Windows XP and offers the ability to format to a very large capacity Hard Disk, along with enhanced security features for files stored using this system.

If you have the opportunity to select a system from these to format your Hard Disk, be aware that these system are not generally forwards-compatible. To clarify this, Operating Systems installed on Hard drives using FAT16 will not be able to access files on another Hard Drive (or partition) which has been formatted using FAT32 or NTFS.

The same can be said for FAT32 and NTFS. However, FAT32 can read FAT16 and NTFS is clever enough to read both FAT16 and FAT32.

When the PC wants a particular file from the Hard Drive, it reads the FAT - File Allocation Table (in other words, the index) and uses the information it finds to get the file from the appropriate area of the Hard Disk. Similarly, if it wants to add a new file to the Hard Disk, it will place it in the next suitable space, then record in the FAT exactly where it left it.