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Formatting
Every storage media must be formatted before it can be used. The utilities used for formatting behave differently when acting on hard disks than when used for floppy disks. Formatting a hard disk involves the following steps:
Low-Level Formatting:
This is the actual formatting process for the disk because it creates the physical structures such as tracks, sectors and control information etc., on the hard disk.
Low level format creates the physical format that defines where the data is stored on the disk. Low-level formatting is the process of outlining the positions of the tracks and sectors on the hard disk and writing the control structures that define where the tracks and sectors are.
The first time that a low-level format is performed on a hard disk, the platters of the disk start out empty and that is the last time the platters will be empty for the life of the drive, if you have not used the data wiper or zero-fill utility on it later. The zero-fill utilities are used to wipe out the hard disk platters as like new by erasing all the data on it.
Partitioning:
This process divides the disk into logical parts that assign different hard disk volumes or drive letters.
Hard drive partitioning is one of the most effective methods available for organizing hard drives. Partitions provide a more general level of organization than directories and files. They also offer greater security by separating data from operating systems and applications.
Partitions allow you to separate data files, which must be backed up regularly from program and operating system files. Partitioning becomes a necessity for the hard drive if you are willing to load, more than one operating systems in the disk otherwise in most of the cases it is possible that you may lose your data.
The first sector of any hard drive contains a partition table. This partition table only has room to describe four partitions. These are called primary partitions. One of these primary partitions can point to a chain of additional partitions. Each partition in this chain is called a logical partition. We shall discuss the partition basics with logical approach in details, in the next chapters.
High-Level Formatting:
It defines the logical structures on the partition and places at the start of the disk any necessary operating system files. This step is also an operating system-level command.
The FORMAT command of DOS that is FORMAT.COM, behaves differently when it is used on a hard disk than when it is used on a floppy disk. Floppy disks have simple, standard geometry and cannot be partitioned, so the FORMAT command is programmed to automatically both low-level and high-level format a floppy disk, if necessary but in case of hard disks, FORMAT will only do a high-level format.
When we have completed low–level formatting, we have a disk with tracks and sectors but nothing written on them. High-level formatting is the process of writing the file system structures on the disk that let the disk be used for storing programs and data.
If you are using DOS, the FORMAT command (that is FORMAT.COM), performs this work by writing such structures as the DOS boot record file allocation tables and root directories to the disk. High-level formatting is done after the hard disk has been partitioned.
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