FILE SYSTEM Presented By Neelam Waqar Roll no:46
CONTENTS: • FILE S SYSTEM • DIFFERENT FILE SYSTEMS • FILE SYSTEM COMPONENTS • FILE OPERATIONS • LOG STRUCTERD FILE SYSTEM • FILE EXAMPLES
FILE DEFINITION: • A collection of data or information that has a name, called the filename. • Almost all information stored in a computer must be in a file. There are many different types of files: data files, text files , program files, directory files, and so on. Different types of files store different types of information. Text file : A file that contains characters from the ASCII or Unicode character sets.
FILE SYSTEM: • In a computer, a file system is the way in which files are named and where they are placed logically for storage and retrieval. • Without a file system, information placed in a storage area would be one large body of information with no way to tell where one piece of Information stops and the next begins. • File systems can be used on many different kinds of storage devices.
TYPES: • There are many different TYPES of file systems. Each one has different structure and logic. Each one has different properties of speed, flexibility, security, size and more.
FLAT FILE SYSTEM: • A system of organizing files in an operating system in which all files are stored in a single directory.
FAT file SYSTEM: • The FAT File system is used by DOS and is supported by all the other operating systems. It is simple, reliable, and uses little storage. • The family of FAT file systems is supported by almost all operating systems for personal computers, including all versions of Windows.There are three versions of FAT • FAT12:The initial version of FAT introduced in 1977. • FAT12 was used for old floppy disks. • FAT12 may use up to 4096 different block references .
FAT16: • The first file system to be used on a Microsoft operating system was the FAT system, which uses a file allocation table. • The FAT system is a 16-bit system that allows files to be identified by a name consisting of up to 8 characters and a 3 character extension, which is why this system is called FAT16. • The FAT12 and FAT16 file systems had a limit on the number of entries in the root directory of the file system. FAT system is limited to 65,525 clusters. • If users want to store a 50KB file in a 1000MB sector, you will use 4 clusters because the capacity of one cluster is 16KB.
ADVANTAGES OH FAT16: • MS-DOS, Windows 95, Windows 98, Windows NT, Windows 2000, and some UNIX operating systems can use it. • There are many tools available to address problems and recover data. • If you have a startup failure, you can start the computer with an MS-DOS bootable floppy disk. • It is efficient, both in speed and storage, on volumes smaller than 256 MB.
DISADVANTAGES OF FAT16: • No built-in file system security • No utility to compress files • Due to large cluster size, it wastes the storage space for larger drives • File size more than 2GB cannot be created • Larger the hard disk, large is the wastage of storage space • As the size of the cluster increases, Inefficiency on larger volume sizes increases
FAT32: • A version of the file allocation table (FAT) available in Windows 95 and Windows 98. FAT32 increases the number of bits used to address clusters and also reduces the size of each cluster. • It uses 32-bit values for the FAT entries. In fact, only 28 bits are used, as 4 bits are reserved for future use. • FAT 32 is popularly used in external storage devices.FAT32 file systems on XP will conduct a file check if windows was not shut down properly. • This will more or less guarantee that no file system problems arise. NTFS however does not perform such check like memory cards, USB drives, etc.
Contind.. • The FAT32 format is widely used for USB drives, flash memory cards and external hard drives for compatibility on all platforms (Windows, Android tablets, etc.) • Data loss is common problem faced by FAT partitions users. If you have lost data from FAT16 or FAT32 format storage units, no need to worry as you can recover FAT partition with Remo Recover (Windows) software. • Usage: The FAT32 file system is typically used as a means of file storage in a Windows 9x computer.
NTFS:NEW TEHNOLOGY FILE SYSTEM • The NTFS file system was introduced with the first version of Windows NT (New Technology) and is a completely different file system from FAT 16 and Fat 32. • Microsoft actually designed it to be more stable, reliable and offer end users greatly increased security. NTFS supports hard drive sizes up to 256TB • NTFS provides everything. , NTFS is less attractive on personal desktop workstations or portables. It uses 64-bit values for FAT entries. • It is used for retrieving and storing files on the hard disk. NTFS was initially designed for the Intel i860 XR processor released by Microsoft in 1993.
exFAT: • exFAT (Extended File Allocation Table) is a Microsoft file system optimized for flash drives. • Extended file allocation table (exFAT) is a new file system that is better adapted to the growing needs of mobile personal storage. • It is supported in Windows XP and Windows Server 2003 ,Windows Vista with Service Pack 1,Windows Server 2008,Windows 7, Windows 8, Windows Server 2008 R2 (except Windows Server 2008 Server Core). • exFAT can be used where the NTFS file system is not a feasible solution or where the file size limit of the standard FAT32 file system is unacceptable.
Contind… • exFAT is also supported in a number of media devices such as modern flat panel TVs, media centers, and portable media players. • Handles more than 4000 RAW images, 100 HD movies, or 60 hours of HD recording in a single directory. • It was developed by Microsoft and originally released in November 2006.
File System Components: • Disk management organizes disk blocks into files • Naming provides file names and directories to users, instead of tracks and sector numbers. • Protection keeps information secure from other users • Reliability protects information loss due to system crashes