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Table Of Contents  CertiGuide to A+ (Operating Systems)
 9  Chapter 0011:  DOS
      9  V  File-Related DOS Commands

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Perhaps you may wish to use the following analogy when thinking of FDISK.

If you were going to setup a farm in the ‘back 40’, you would need a house to live in, a barn and fields.

The first step would be to survey the land and plant little plastic flags to define where the house would be built relative to the fields and the barn. FDISK is the digital version of planting the survey flags.

Depending on the version of DOS or Windows you are using, you may (or may not) get a choice about supporting large hard drives. If you don’t get a choice, you are going to create the digital version of planting survey flags using what is known as FAT 16, frequently referred to simply as FAT. The 16 means it can allocate areas using the 16th power of 2(16^2).

That makes a hard math limitation of 4 gigabytes (GB) of storage, assuming each storage cluster uses 64 kilobytes (64kb). Beginning with Windows 95 b (or osr2) FAT was dramatically improved. Several changes were made to FAT. The most important ones include:

Support for up to 2 terabytes (2TB) per drive partition.

(Terabyte is 1000 Gigabytes GB)

smaller clusters sizes, resulting in a 10-15% gain in storage efficiency.

These points and more about the different ways to plant digital survey flags were discussed in the file systems chapter earlier in the book.

FAT 32

can store the same data using less space.

NT4 cannot read FAT32 drive partitions

Regardless of which version of FDISK that is available to you, several items are common to FDISK. They are:

FDISK must be run first.

DOS must reboot for FDISK changes to take effect.

Installing DOS

The proper order for installing DOS or windows is: FDISK, reboot, FORMAT.

8 Practice FDISK

Figure 142: FDISK large disk support message


After you have planted the digital survey flags, construction can begin. The next step in building the digital house is the FORMAT command. All storage media must have some form of formatting to give it a structure. Common drive format structures discussed in the previous chapter include:

  • FAT (file allocation table 16 bits)

  • FAT32 (file allocation table 32 bits)

  • NTFS (new technology file system)

  • CDFS (compact disk file system)

Once a drive is formatted, DOS or Windows can be installed. Installing DOS can be accomplished immediately after formatting by using the /s switch with FORMAT. Simply type:


As soon as the hard drive is formatted, it will copy IO.SYS, MSDOS.SYS and COMMAND.COM to the hard drive. Specifically, it copies these file to track 0 of either a floppy drive or a hard drive. should you find yourself behind the 8 ball because you were playing with another operating system or caught a digital virus that infects track 0, you can sometime repair by using the command:


The /MBR switch stands for master boot record.

Virus Innoculation

If a boot sector virus is suspected, try FDISK/MBR.

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V  File-Related DOS Commands
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