How to use FDISK, FORMAT, and SYS to setup a new Seagate ATA drive

Instructions for formatting and partitioning an internal drive using FDisk and other related Windows 98SE and Windows ME tools.

Please note that these tools are only needed by older versions of Windows (95,98, ME). If you are using Windows 7, Vista, XP, or 2000, you should not need to run these tools.

Before proceeding with installing an operating system (DOS/Windows 9x), the drive must first be partitioned and formatted. A drive/partition will not be assigned a drive letter and can not be formatted until partitioned using FDISK or a similar utility. If the new drive is a second drive, partitioning and formatting can be done within Windows. Go to the DOS Prompt and run FDISK to set up partitions. A second drive can be formatted within Windows by right clicking the drive in My Computer or Windows Explorer and selecting Format. If the new drive is to be the boot drive, then a startup diskette will need to be used (Windows Me requires the distribution CD to build a bootable hard drive). The startup diskette should be included with the operating system or one can be made from within Windows. A Startup disk can be made by going to Start> | Settings | Control Panel | Add/Remove Programs | Startup Disk tab. Place the startup diskette into the A: drive and reboot the computer.

After configuring the new drive as master or slave and configuring system BIOS for the new drive, boot the system with the startup disk in drive A:. At the prompt, type FDISK and <enter>.

After the FDISK utility starts, the first screen (if using FAT32 version) should ask if you want to use Large Drive support. If your drive is over 512 MB and you want to make partitions over 2 GB, answer Yes. The next screen should be a menu with either 4 or 5 numbered selections.

FDISK Options
Current Fixed Disk Drive: 1

Choose one of the following options

  1. Create DOS Partition or Logical DOS drive
  2. Set Active Partition
  3. Delete partition or Logical DOS drive
  4. Display partition information
  5. Change current fixed disk drive (Only if more than one drive is present)

Enter Choice [ ]

Option 1 is used to create a Primary DOS partition or an Extended partition and set the partition(s) size. Use Option 2 to set the boot partition as Active (only one partition can be set Active using FDISK). Option 3 is used to delete partitions (Primary DOS, Extended, Non-DOS). Option 4 displays all settings for each partition. Option 5 lets you select which Fixed Disk to partition (maximum of 4 fixed disks with FDISK).

After all configurations are made, use the ESC key to exit the program. Before the drive can be Formatted, the computer will need to be re-booted in order for the new partitions to be given a Drive Letter.

Steps for partitioning a hard drive using FDISK

  1. If you're in Windows, open a DOS window.
  2. From the C: prompt, type "FDISK" and press ENTER.
  3. If you're changing the partitions on an existing disk, choose option 4 from the FDISK menu to display existing partition information.
  4. If all of the space on the drive is already partitioned, you will need to use FDISK menu option 3 to remove existing partitions before creating new ones.
  5. For a new drive from which you will boot your PC, you must first create a Primary DOS Partition. Choose option 1 from the FDISK main menu and Select option 1 from the Create menu to create a Primary DOS Partition.
  6. If you only want to have one partition on the drive, type Y when prompted to make one large partition. If making multiple partitions, type N.
  7. Enter the size for the partition if you selected N in step 6.
  8. To create an extended (non-bootable) DOS partition, choose option 1 from the main FDISK menu, then option 2 from the Create menu.
  9. Press enter to use all remaining available space for the partition.
  10. Create logical drives on the extended partition by entering the desired size(s) in MB or percent of disk space.
  11. Continue until all available space is assigned to logical drives.
  12. If you will be booting from this disk, choose option 2 from the FDISK menu and enter 1 to make the primary DOS partition ACTIVE.
  13. Press the ESC key to exit FDISK. If running from Windows 9x, you must manually reboot your PC at this point. You must format all partitions before they can be used.


  1. If you are using a 16 bit OS (Windows 3.x or DOS), do not use the maximum available size for your Primary DOS Partition on a drive larger than 2GB or you will be unable to use the rest of the space.
  2. Before repartitioning an existing drive, be sure to make a good backup of all of the data on the drive. FDISK will destroy all existing data on the drive.
  3. There are utilities (e.g., Partition Magic) that can re-partition existing drives without destroying data or minimizing data loss.

No Fixed Disk present
This means FDISK is unable to find your hard disk drive. Insure that the hard drive is properly setup in CMOS. If the drive is setup properly in CMOS, double check all cable connections on the hard disk drive and the System board. Also make sure all ATA devices are configured as Master or slave.

Drive Lettering
Drive letter assignment is dynamic, meaning DOS/Windows hands out drive letters in sequence each time the computer boots. Booting to a DOS/Windows floppy and running FDISK /STATUS is a quick way to see how the operating system has assigned hard drive letters. DOS/Windows (FAT File Structure) is limited to four Primary DOS partitions and can only assign one Primary DOS partition per physical hard drive. Using Extended Partitions and Logical Drives, you are only limited by the alphabet for Drive Letters.

Every device in your computer has a priority. Drive letters A: and B: are reserved for the Floppy drives. Hard Drives begin with Drive letter C:. Primary DOS partitions have priority over Extended DOS partitions. Therefore, the bootable floppy drive is A:, the non-bootable floppy drive (if present) is B:, the first Active (bootable) primary partition on the first hard drive is C:. Any logical drives or Extended DOS partitions would become D:, E:, F:, etc. (Some networking software reserves Drive Letters starting with F:).

If a second hard drive is in the system, the second Primary DOS partition would be D: and then logical drives or Extended DOS partitions on the first drive would then become E:, F:, G:, respectively (Primary DOS has priority over Extended DOS) followed by any logical drives or Extended DOS partitions on the second drive.

After four Primary DOS partitions have been used, the next priority is for devices loaded by an external BIOS such as SCSI devices. The last priority is for devices controlled by "block mode" drivers loaded from the CONFIG.SYS and/or AUTOEXEC.BAT; most CD-ROMs fall in this category and their drive letters are assigned when the MSCDEX.EXE loads. RAM drives, Parallel Port drives, and Double Spaced or Stacked drives also fall into this category. If the CD-ROM device driver is loaded first, it gets the next available drive letter.

When you add a new device, it will get the next available letter following the above mentioned priority assignment and displace any device using that letter. The displaced device will pick up the next available drive letter, and all associated drivers for the displaced device may need to be reconfigured, a common occurrence when adding a second hard drive to a system with a CD-ROM.

After a drive is partitioned with FDISK, each partition must be Formatted to make it useable by the Operating System. After re-booting to the A:> prompt, type FORMAT x: (x= drive letter) and <enter>. If this is to be the boot drive, use FORMAT C: /S and <enter> to format the drive and make it bootable by transferring the system files (Windows Me requires the distribution CD to make a drive bootable). The FORMAT command will ask a couple of times if you are sure you want to continue with the operation with the warning that Formatting will destroy all data on the drive. If sure, select Yes. The Format command should start the process and show a percent of drive formatted.

If this is a second drive and you are using Windows 95/98, double click the My Computer icon on your Windows desktop. Right click on the first partition of your new drive and choose Format. If this will become the new boot disk, be sure to check the box at the bottom that says "Copy system files." Choose full format. Give the drive a label of up to 11 letters and/or numbers if you like. Click the Start button to begin formatting. You must repeat these steps for each partition you created on the new drive.

This command can be used to transfer a fresh copy of system files to a drive that has been partitioned and Formatted (Windows Me will not allow use of SYS command to transfer the system). This will not destroy any data on the drive, but will simply replace the current system files with the ones from the source disk. This is a good way to refresh a drive that has data on it but will no longer boot. Use: SYS x: (x= Drive letter to be refreshed).



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