Tuesday, July 29, 2008

File System

File System
There are three basic file systems in windows. They are FAT, FAT32, and NTFS.

FAT (File Allocation Table)
1. FAT system divides sectors of physical disk (eg. hard disk) into allocation units called clusters.
2. FAT is also known as FAT16
3. it has existed in its present from in MS-DOS since version 4.0
4. Maximum size for FAT16 is 2GB.
5. FAT directories can only support filenames of eight characters with a three-character file extension (eg. exe)
6. FAT's attributes is simple - one byte and eight possible attributes.
7. Works well with small partitions that have relatively few files.

1. It is the FAT system with 32-bit number internally.
2. It is not designed to operate with fewer than 64K clusters, but can go up to 232 cluster (about 4 billion).
3. FAT32 needs a larger cluster size only when partitions reach 2TB.
4. FAT32 can be used only by windows 2000, Windows98 and Windows95 OEM service release 2.

NTFS (The New Technology File System)
1. It was developed from HPFS (High Performance Filing System) which was introduced in OS/2
2. The major difference with FAT system is that the information about file allocation is not stored at the start of the partition.
3. Provides support for links within the file system.
4. NTFS has the capability to support very large file systems.
5. NTFS security comes in the following four sections:
a. Logon - every user must uniquely identify themselves.
b. Ownership - every resources on the system owned by a user.
c. Permission - resource on system is at the discretion of its owner.
d. Auditing - any permission that has been granted is recorded.
6. NTFS is the only file system that supports local security.