Any Hard Disk that comes with a computer must be prepared for use before formatting and installing the operating system. This includes Low Level Formatting and running the DOS program FDISK (Fixed Disk). Low level formatting is generally done at the factory before the drive is released for sale. Note that not all computers will effectively handle all types of operating systems. i.e. It is a waste of time trying to install Microsoft Windows 95 onto a 80286 processor computer or onto a hard drive with a capacity of less that 120-150 Mb.

The following information is (in part with adjustments and deletions) extracted from the On Line Microsoft TechNet DataBase at http://www.microsoft.com/. Access this page and search for 'System Checkout'.

To use a hard disk after it has been installed in a computer, the following four requirements must be met:

1. Identify the drive type in the computer's setup program.

2. The drive must be or must have been low-level formatted.

3. Run FDISK or an equivalent utility to define partitions.

4. At the DOS prompt, type "format c: /s" (sans quote marks) to write logical formatting to the disk.

Each of the above steps is outlined below.

1. Identify the drive type in the computer's setup program.

XT Computers

XT computers usually don't require this step of identifying the drive TYPE. It is included by the drive-specific low-level formatting program described in step 2. For XTs that have CMOS, and therefore have a setup program that may expect the drive TYPE definition, the following information in the AT Computers section applies.

AT Computers

On AT (286 or higher) computers, the drive TYPE needs to be identified in the computer's setup program. The setup program may be called Setup, Diagnostics, or Diags, depending on the manufacturer. To run the setup program, boot from the setup disk (for example, IBM PS/2 Reference disk, Wyse 386 Setup disk), or if the ROM BIOS has a built-in setup program, consult the computer's manual on how to invoke setup, (generally pressing F2 or DEL on startup).

You have to enter the drive TYPE and issue the save command. This causes the setup program to write the drive TYPE (and other) information into the computer's CMOS, which is a battery-backed memory that the computer reads and then compares to what it actually detects in the system each time it is turned on. If there is a discrepancy, an error is issued and you are prompted to run the setup program to update the CMOS information.

The drive TYPE is an arbitrary number assigned by the computer manufacturer (not the drive manufacturer) to identify a drive with a certain number of cylinders, heads, and sectors. For example, an 80 MB Seagate hard drive may be TYPE 42 on a COMPAQ and TYPE 17 on a Wyse computer. On newer computers most drive types are identified as type 47. This means that the BIOS can automatically detect the type of hard drive installed.

A computer may not have a drive TYPE available to match the characteristics of a particular drive. In this case, a TYPE needs to be selected that has the same number of heads or less. This is also true for the number of cylinders and sectors.

2. The drive must be or must have been low-level formatted.

Low Level formatting is a process that occurs below the normal DOS level and marks the sectors on a Hard Disk. SCSI and IDE drives are usually already low-level formatted at the factory. In this case, you may continue with step 3.

AT Computers

On AT computers, low-level formatting programs are usually a choice on the setup program's menu, or these formatting programs come with the computer on a separate disk.

XT Computers

On XT computers, you usually have to invoke the DOS DEBUG utility to access a hard-drive-specific program on the controller's ROM to low-level format the drive. Information about DEBUG commands is usually provided in the hard-disk-controller-manufacturer's guide.

3. Run FDISK or an equivalent utility to define partitions.

To invoke this program, boot from drive A, insert the disk with the file FDISK.COM, and press the [ENTER] key after you type the following: FDISK

The DOS FDISK (Fixed DISK) utility allows you to specify partition sizes and to define which partition will be the active (boot) partition. FDISK then writes the partition table into the first sector of track zero of the partitionable disk. This partition table also contains the master boot block. When the machine is turned on, the ROM BIOS will read this master boot block and transfer control to it. The master boot block then finds out which partition is active, reads the boot code from that partition, and then transfers control to that boot code.

Some versions of DOS have different names for this utility, and some third-party utilities replace FDISK (for example, Diskmanager from ONTRACK Systems) and include many more diagnostic and other features.

4. At the DOS prompt, type "format c: /s" (sans quote marks) to write logical formatting to the disk. To invoke this program, boot from drive A, insert the disk with the file FORMAT.COM, and press the [ENTER] key after you type the following:

FORMAT C: /S

The formatting process creates a system of tables, directories, and sector numbers that allows DOS to quickly find certain bytes in a vast sea of 20, 40, or 200 megabytes. This system consists of the following:

1. The boot record

2. The file allocation table

3. The root directory

4. The data area

The "/S" parameter forces FORMAT.COM to transfer the two hidden system files IO.SYS and MSDOS.SYS (for IBM-DOS: IBMBIO.COM and IBMDOS.COM), and the command processor COMMAND.COM from the boot floppy disk to the hard drive. This allows you to boot with the hard drive.