How do I utilize FDISK?

The program that DOS supplies for setting up hard disk partitions is called FDISK, which is believed to stand for “fixed disk”, an older term for hard disk. FDISK is used only for DOS (FAT) partitioning, and allows the user to perform the following functions:

Create Partitions:

FDISK allows you to create a primary DOS partition or logical DOS volumes. To create a logical DOS volume you must first create an extended DOS partition, since the logicals are contained within the extended partition.

Set Active Partition:

You can use FDISK to set the primary partition on your boot disk active, allowing it to boot. It’s strange that FDISK doesn’t do this automatically when you create the boot primary partition (since there can only be one primary DOS partition anyway), but you must do this manually in many cases. (At least FDISK warns you when no disk is set active, via a message at the bottom of the screen.)

Delete Partitions:

FDISK will let you delete partitions as well. This is the only way to change the size of a partition in FDISK. You have to delete the old one and create a new one with the new size. If you want to change the size of the primary DOS partition using FDISK you must delete every FAT partition on the disk and start over… annoying, but necessary


Display Partition Information:

The last option that FDISK gives is to display the partition information for the system. It will first show the primary and extended partitions and then ask you if you want to see the logical drives within the extended partition. In fact, if you want to see this information, you can just do “FDISK /STATUS” from the DOS command line. This will show you the partition information without taking you into FDISK, and therefore, you run no risk of accidentally doing something you’ll wish you hadn’t. Which in reality is always a good thing!


Some important points that you should keep in mind when using FDISK:


Be very Careful:


  1. ¬†With just a few keystrokes, FDISK can wipe out part or all of your hard disk. Generally speaking, don’t use FDISK unless you need to, and make sure you understand what you are doing before you begin.


  1. Run It From DOS: Windows 95 allows you to run FDISK direct from the graphical user interface, and even while other applications are open and running. Since FDISK alters critical disk structures at a very low level, running it while files are open and other applications are using the disk is asking for trouble. To be safe, always exit to DOS (“Restart the computer in MS-DOS mode”) before using FDISK (except for using “FDISK /STATUS”, will work safely from within a DOS box in Windows 95/98, remember, you’re not changing anything). FAT32 Support: The version of FDISK that comes with Windows 95 OEM SR2 supports the creation of partitions that use the FAT32 enhanced file system for larger volumes. Some clever person at Microsoft decided not to call it FAT32 however within this program. Instead, when you run FDISK on a system that has Windows 95 OEM SR2 installed, and a hard disk over 512 MB (the minimum for using FAT32), you will receive a message asking you if you want to “enable large disk support”. If you answer “Y” then any new partitions created in that session will be FAT32 partitions. Note: It is often useful to include FDISK as one of the programs on a bootable floppy. This way you can use it when setting up new hard disks. Considering how important it is, FDISK is a rather primitive program. It works, but it’s cryptic and hard to use. Anything you can do in FDISK you can do more flexibly and easily using a third-party program like Partition Magic. FDISK will not allow you to select or change cluster sizes, resize partitions, move partitions, etc. FDISK’s primary advantage is, of course, that it is free (well, built-in anyway).


Windows NT uses a program called Disk Administrator to handle disk setup tasks. In essence, this is an enhanced version of FDISK that allows you not only to manipulate partitions, but also access some of NT’s unique disk management features like NTFS. I added this because not everyone uses the same operating systems. And things are a handled slightly different, but if they didn’t, everyone would just be using the same thing. That would just be boring.