Appendix A. Partitions And File Systems; Hard Disk Partitions; File Systems; A.2 File Systems - ACRONIS TRUE IMAGE 8.0 User Manual

Appendix A. Partitions and file systems

A.1

Hard disk partitions

The mechanism that allows you to install several operating systems on a single PC
or to carve up a single physical disk drive into multiple "logical" disk drives is called
partitioning.
Partitioning is performed by special applications. In MS-DOS and Windows, these
are FDISK and Disk Administrator.
Partitioning programs perform the following:
• create a primary partition
• create an extended partition that can be split into several logical disks
• set an active partition (applied to a single primary partition only)
Information about partitions on a hard disk is stored in a special disk area – in the 1
of cylinder 0, header 0, which is called the partition table. This sector is called the master boot
record, or MBR.
A physical hard disk might contain up to 4 partitions. This limit is forced by the partition table
that is suitable for 4 strings only. However, this does not mean you can have only 4 operating
systems on your PC! Actually, existing applications called disk managers support far more
operating systems on disks. For example, Acronis OS Selector enables you to install up to 100
operating systems!
A.2

File systems

An operating system gives the user the ability to work with data by supporting some
type of file system on a partition.
All file systems are made of structures that are necessary to store and manage
data. These structures are usually composed of operating system boot sectors,
folders and files. File systems perform the following basic functions:
• track occupied and free disk space (and bad sectors, if any)
• support folders and file names
• track physical location of files on disks
Different operating systems use different file systems. Some operating systems are
able to work with only one file system while others can use several of them. Here
are some of the most widely used file systems .
Copyright © Acronis, Inc., 2000–2004
Appendix A Partitions and file systems
st
sector
65