File SysteM

File system

What is FAT?


FAT stand for File Allocation Table. FAT is the primary file system for various operating systems including DR-DOS, OpenDOS, freeDOS, MS-DOS, OS/2(v1.1), and Microsoft Windows (up to Windows Me).

The successive major versions of the FAT format are named after the number of table element bits: 12, 16, and 32. The FAT standard has also been expanded in other ways while preserving backward compatibility with existing software. FAT12 now referred to the initial version of FAT. FAT12 remains in use on 1.44MB floppy disks. With the standard hard disk sector size of 512 bytes, this gives a maximum of 32 KB clusters, thereby fixing the "definitive" limit for the FAT16 partition size at 2 gigabytes. For historical reasons, FAT12 and FAT16 media generally use 512 root directory entries on non-floppy media. Other sizes may be incompatible with some software or devices.

In order to overcome the volume size limit of FAT16, Microsoft implemented a newer generation of FAT, known as FAT32, with cluster values held in a 32-bit field, of which 28 bits are used to hold the cluster number, for a maximum of approximately 268 million (228) clusters. The maximum possible size for a file on a FAT32 volume is 4 GB minus 1 "null" byte (232−1 bytes). Windows 2000 and Windows XP can read and write to FAT32 file systems of any size, but the format program included in Windows 2000 and higher can only create FAT32 file systems of 32 GB or less. This limitation is by design and according to Microsoft was imposed because many tasks on a very large FAT32 file system become slow and inefficient.



What is NTFS?


NTFS stand for New Technology File System. NTFS is the standard file system of Windows NT, including its later versions Windows 2000, Windows XP, Windows Server 2003, Windows Server 2008, and Windows Vista. NTFS supersedes the FAT file system as the preferred file system for Microsoft’s “Windows”-branded operating systems. NTFS has several improvements over FAT and HPFS (High Performance File System) such as improved support for metadata and the use of advanced data structures to improve performance, reliability, and disk space utilization, plus additional extensions such as security access control lists (ACL) and file system journaling.


What is CDFS?


Short for CD-ROM File System, the Windows 95 driver for CD-ROM players. CDFS replaces MSCDEX, which was used for DOS and Windows 3.x systems. Unlike MSCDEX, which is a 16-bit program that runs only in real mode, CDFS is a 32-bit program that runs in protected mode. In addition, it uses the VCACHE driver to control the CD-ROM disk cache, which results in much smoother playback.


What is EXT2?


The ext2 or second extended file system is a file system for the Linux kernel. The reason for some limits of the ext2-file system are the file format of the data and the operating system's kernel. Mostly these factors will be determined once when the file system is built. They depend on the block size and the ratio of the number of blocks and inodes. Block sizes of 8 KB are only possible on alpha-architectures by default. The operating systems supported for Linux, BSD, Windows (through an IFS), Mac OS X. max volume size 16 to 32 TiB(tebibyte).


What is EXT3?

The ext3 or third extended filesystem is a journaled file system that is commonly used by the Linux operating system. It is the default file system for many popular Linux distributions. The ext3 file system adds, over its predecessor:

Without these, any ext3 file system is also a valid ext2 file system. This has allowed well-tested and mature file system maintenance utilities for maintaining and repairing ext2 file systems to also be used with ext3 without major changes. The ext2 and ext3 file systems share the same standard set of utilities, e2fsprogs, which includes a fsck tool. The close relationship also makes conversion between the two file systems (both forward to ext3 and backward to ext2) straightforward.

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