Hard Disk And File Systems
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A.5
Extended Partitions
The extended hard disk partition was developed as a way to avoid the four-primary-
partitions limit. The extended partition is used only for creating a desired number of
logical partitions
.
An extended partition does not contain any data directly.
A.6
Logical Partitions
An extended partition can be divided into any number of logical partitions; these are
similar to primary partitions in that they can contain operating systems, applications and
user data.
Primary partitions should be used for booting operating systems, system files and folders.
Logical partitions can contain any other information, as they are accessible by most
operating systems.
If you need several operating systems, you should use logical partitions for booting
purposes and leave primary partitions free.
A.7
Formatting Hard Disks
Within each of the partitions, information has to be organized in a way understandable to
the operating system using that partition. This organization is the
file system
.
As a rule, a formatting program performs the following functions:
•
It creates the boot record
•
It creates the file allocation table (FAT)
•
It identifies and marks bad clusters on the disk so they are not ever used afterwards
After formatting, logical disks are organized as follows:
•
Logical disks start with the boot sector
•
One or several copies of the file allocation table (FAT) are placed after the boot sector
•
A root folder is created
•
The data area is created
Each logical disk has to be formatted with the FORMAT command separately.
