How to FDISK a Hard Drive

To create DOS partitions on a hard disk you must run FDISK utility from the DOS command prompt. You can FDISK from a Windows 95/98 DOS session, but only if you do not intend to work with the currently active partition. Obviously, if you destroy the partition containing the system files and operating system the computer is currently using, the system will halt and come to attention as soon as you exit FDISK.

After you create a partition, exit FDISK and reboot the system, you will find that the system has assigned the new partition a drive letter. You can switch to that drive letter from DOS prompt, but cannot read from it or write to it because the drive has not yet been formatted.

You must use the FORMAT utility from the command line, the Windows Explorer, or the My Computer window to format the drive before you can use it to store data.

In most cases it is best to run FDISK from a boot floppy, so that you can continue to access the machine even if there are no partitions on the hard disk. You can create a Windows 98 start up disk by launching Add/Remove Programs from the Control Panel, selecting the Startup Disk tab and following the instructions you will find there.

Windows 95/98 startup disk include the system files needed to boot the computer to the DOS Prompt, as well as the FDISK and FORMAT utilities you need to prepare the hard disk for a full Windows installation.

1. Boot with the Bootdisk/Startup Disk which will take you to the A:\> prompt.

If your system contains a hard disk drive with a capacity greater than 512 megabytes you can see the following message when you run FDISK.

Your computer has a disk larger then 512 MB. This version of Windows includes improved support for large disks, resulting in more efficient use of disk space on large drives, and allowing disks over 2 GB to be formatted as a single drive.

IMPORTANT: If you enable large disk support and create any new drives on this disk, you will not be able to access the new drive(s) using other operating systems, including some versions of Windows 95 and Windows NT, as well as earlier versions of Windows and MS-DOS. In addition, disk utilities that were not designed explicitly for the FAT 32 file system will not be able to work with this disk. If you need to access this disk with other operating systems or older disk utilities, do not enable large drive support.

Your response to this question determines whether or not FDISK will create FAT 32 partitions on your hard drive. Under normal circumstances, drives with capacity of less than 512 MB cannot use FAT 32. On the other hand, if you have a large capacity drive and want to create a partition larger than two (2) gigabytes (2GB) in size, you must use FAT 32.

This initail screen is the only indicator that Windows 95 (OSR2,2.5)/98 version of FDISK provides support for FAT 32. The screens that follow are the same, whether or not you enable large disk support.

When you select the Create DOS partitions or Logical DOS drive option, FDISK presents the following options for creating a new partition on the selected hard disk:

Create DOS Partition or Logical DOS Drive

Current fixed disk drive: I

Choose one of the following:

1.Create Primary DOS Partition
2.Create Extended DOS Partition
3.Create Logical DOS Drive(s) in the Extended DOS Partition

Enter choice: (1)

If the disk currently has no DOS partitions, you must first create a primary DOS partition. If the disk does already have a primary DOS partition and there is still unallocated space, you can create an extended DOS partition. Finally, if the disk already has an extended DOS partition and you want to divide it into two drive letters, you can create logical DOS drives in the extended partition.

When you create a new partition, FDISK first asks you if you want to use all of the space available on the disk and make the partition active. This enables you to create the most common partition configuration in one step. If you say no, you are prompted to specify the size of the new partition in megabytes. Alternatively, you can specify a size using a percentage of the free space available by including the percent symbol (%) after the value.

FDISK also prompts you to specify a volume label for the partition. This label can contain up to eleven numbers or letters used to identify the partition. The Windows Explorer and the My Computer window display the volume label along with the drive letter for each local drive on the system.

Making a Partition Active

After you create a partition on your system's first or only hard disk, you will probably want to
make that partition active so the system can boot from it. When you choose the Set Active
Partition option, you are prompted to select the partition that will hold the system boot files.
Only one DOS partition on your computer can be active.

Making a partition active does not in itself make the disk bootable, It only means that the BIOS will turn over control of the system to that partition at boot time. To make the disk bootable, you must also place the system boot files on that partition by formatting the drive with the system files option or by using the SYS utility.

Deleting Partitions

If you select the Delete Partition or Logical DOS Drive option from FDISK's main screen, you'll see a list of the partitions and logical drives on the selected disk. This list includes all the DOS partition types, as well as partitions created by other file systems (which are identified as non-DOS partitions).

Deleting a partition is always a big step that should cause you to stop and carefully consider your actions. Deleting a partition destroys all the data that is currently stored there and, in the case of an active partition, the system boot files as well. FDISK repeatedly prompts you to confirm your actions before it deletes the partition, including a requirement that you enter the volume name of the partition to be deleted. This virtually ensures that entering a random sequence of accidental keystrokes cannot cause you to lose your data.

Obviously, you must back up any important data before you delete the partition where it resides. It is also important to be sure that you have a means of booting your system after the partition is gone. If you delete the active partition, you must have a boot floppy disk, such as a Windows 98 startup disk, to restart the system.

CAUTION
Many of the personal computers sold today use a small non-DOS partition to store a configuration program for the system BIOS. This program is activated when you press a particular key combination during the system boot process (the exact key combination varies depending on the BIOS manufacturer). Be sure not to delete this partition unless you are certain that you have the configuration program on some other medium. Otherwise you might be unable to access the information in the BIOS.

Displaying Partition Information

When you choose the Display Partition Information option, you see a list of all the partitions on the selected disk. The list should look similar to this one:

Display Partition Information

Current fixed disk drive: I

Partition	Status	Type	Volume Label	Mbytes	System	Usage
C:	A	PRI DOS	DRIVE 1	2014	FAT32	l00%

Total disk space is 2014 Mbytes (I Mbyte = 1048576 bytes)

This example shows that fixed disk drive 1 contains a single 2,014-megabyte partition that constitutes 100% of the space on the disk. It is a primary DOS partition that has been set as active and will use the FAT32 file system. FDISK has assigned this partition the drive letter C: and the volume label DRIVE 1:

FDISK is a program that many people look upon with fear and trepidation because of the catastrophic damage that can result from accidental or improper use. The Display Partition Information option is totally safe, however, because this screen contains no controls that can affect the state of the disk.

Changing the Current Fixed Disk Drive

FDISK offers the Change Current Fixed Disk Drive option on its main screen only when it
detects more than one supported disk drive in the system. FDISK can address only one drive
at a time and defaults to the first drive in the system BIOS. To manage the partitions on the
systems other disks, you must first use this option to select the desired drive.

Selecting the option displays a list similar to the following that outlines the disk drives in the system along with their disk numbers, partitions, drive letters, sizes, and the percentage of the disk occupied by each:

Change Current Fixed Disk Drive

Disk	Drive	Mbytes	Free	Usage
1		2014		100%
	C:	2014
2		2014	2	100%
	D:	2012

To change to another disk, you select it by specifying the disk number shown in the left most column of the display, Once you have selected another disk drive, it becomes the default for all of FDISK's other functions until you change it or exit the program. Most of the other screens contain a line that specifies the number of the disk that the program is currently addressing.