File Systems - An overview

            File system is the system that is used to store/retrieve the information or data in a stable way for future purpose in a hard disk. This file system may vary from operating system to operating system. To maintain the communication between one operating system to other install different operating systems in a common file system or mount the relevant file system drives whenever necessary. Let us know the basic Windows file systems and Linux file systems in this article.

Windows File systems

Even though there are several file systems in the various operating system environments, the four major are taking into account normally as far as Windows operating system is concerned.

FAT 16/FAT

            File Allocation Table 16 bit is the expansion of FAT16. FAT is the short form for expressing FAT16 in Windows latest versions in these days. This is the oldest file system which will be no longer in use.

            Access to files on a local partition is available through MS-DOS, all versions of Windows, and OS/2.

FAT 32

            This holds 32 bit for storing data and more securer than FAT16/FAT. This is normally used by the Windows and Linux beginners.

            Access to files on a local partition is available only through Windows 95 OSR2, Windows 98, Windows Millennium Edition, Windows 2000, Windows XP, and products in the Windows Server 2003 family.

Figure 1File System Interface

NTFS

            New Technology File System is the expansion of NTFS which holds advance operations in Windows. This is used for Windows and Linux advanced users. Advanced security, compression, encryption and quota management are the salient features of this file system.

A computer running Windows 2000, Windows XP, or a product in the Windows Server 2003 family can access files on a local NTFS partition. A computer running Windows NT 4.0 with Service Pack 5 or later might be able to access some files. Other operating systems allow no local access.

CDFS

            This is the file system that is used in compact disk which holds the expansion of Compact Disk File System. This is platform independent file system and it can be used for reading as well as writing the information on compact disc. This is commonly used by all kinds of users.

The following table is explained us the difference between the various file systems in the operating system Windows.

Types	FAT 16	FAT 32	NTFS	CDFS
Cluster size	16KB to 64KB	4KB	4KB	No cluster size
Maximum partition size	4GB	32 GB	2TB	700-800MB
Security	No	No	Advanced security policies	-
Compression	No	No	Yes	-
Encryption	No	No	Yes	-
Quota	No	No	Yes	-
Quota Management	No	No	Yes	-

Linux File systems

In Linux operating system, we have four major file systems that are commonly used world wide in these days.

ext2

            This is the file system that is used to install Linux normally little bit earlier. There is no journaling support. We can use this file system now also for installing.

Command to format a partition in ext2   mkfs.ext2

Instance: mkfs.ext2 /dev/hda3

ext3

            It is another file system that is also used to install Linux in these days which holds the journaling facility. The journaling facility is having the online database updation service, which is commonly used in the real-life situations.

Command to format a partition in ext3   mkfs.ext3

Instance: mkfs.ext3 /dev/hda3

            FAT/FAT16/FAT32 file systems can be mounted easily with the ext2 as well as ext3 file systems. For mounting ntfs file system, the third party rpm (tool) has to be downloaded from the internet. (for further reference: http://www.rpmfind.org)

Figure 2 File System Overview

vfat

            FAT/FAT16/FAT32 is considered as vfat as far as Linux operating system is concerned. Virtual File Allocation Table is the expansion of this file system. This is generally used for sharing files between Windows and Linux.

swap

            This is the special type file system which doesn’t have the mount point in Linux. This is creating virtual memory for running other applications in the operating system specified. Normally it has the size of the double of the RAM size of the specified system.

The following table explains about the various file systems in Linux

Types	Ext2/Ext3/vfat	Swap
Mount point	Yes	No
Accessed by Windows	No	No
Can it access Windows	Yes	Yes
Partition size	User’s wish	User’s wish / double the RAM size normally
Quota	Yes	Not applicable
Reformatted	Yes	Not applicable
Priority setting	Can’t set	Can set

Note:

1. There is no explicit swap file system in Windows environment. Virtual memory is using to replace the swap file system in Windows.
2. If in the case of installing dual operating systems in a single machine (say Windows 2003 and Linux Enterprise 5.0), we can fix the swap file system as a single file.
3. The administrator can expand the virtual file system in Windows after installing the specified operating system. Similar to that the swap file system size can be extended after installing operating systems. More than one swap file system partitions can be created and fixed up the priorities for those things in Linux environment.

Related Topic:

DFS (Distributed File System) is another file system that is available Windows 2003 server. It is used to distribute the information through out the network in windows environment only.

Distributed File System (DFS) can be used to make it easier for users to access and manage files that are physically distributed across a network. With DFS, can make files that are distributed across multiple servers appear to users as if they reside in one place on the network.