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FILE SYSTEMS

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File system

In a computer, a file system is the way in which

files are named and where they are placedlogically for storage and retrieval.

It organizes files and manages access to data.

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File Systems

The operating system keeps track of data (documents,pictures, etc.) by placing it into a file.

To store and retrieve files: Disk divided into tracks

Tracks are divided into sectors

Sectors grouped into clusters

Number of sectors in a cluster is determined by

Size of the hard drive

File allocation system FAT, FAT32, NTFS

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OS and File System

CompatibilityOperating SystemOperating System FAT16FAT16 FAT32FAT32 NTFSNTFS

Windows XPWindows XP

Windows 2000Windows 2000

Windows NTWindows NT

Windows 95, 98, MEWindows 95, 98, ME

Windows 95Windows 95

MSMS--DOSDOS

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A file system defines the structure and therules used to read, write, and maintaininformation stored on a disk.

Which system used is determined by;

Hardware

Software

Security needs

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File system is responsible for:

File management providing the mechanisms for files to be stored, referenced,

shared, and secured

Auxiliary storage management

Allocating space for files on secondary and tertiary storage

devices.

File integrity mechanisms

Ensuring that the information stored in a file is uncorrupted.

Access methods

How the stored data can be accessed.

.

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FAT???

File allocation table where the OS records how the

disk space is used

File AllocationTable (FAT) is a file system developed byMicrosoft for MS-DOS and was the primary filesystem for consumer versions of Microsoft Windowsup to and including Windows Me.

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File Systems

FAT12: The earliest version the file system, FAT12 allows apartition to contain up to 4096MB/ (212)clusters.

FAT 16: oldest, created for DOS, supported by most OSs,cannot be installed on partitions larger than 2GB, or on hard driveslarger than 4GB.

FAT 32: supports disks from 512MB to 2TB, compatible withWindows 98 and up

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Tracks

Sectors

within a

Track

Cluster

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A cluster, also known as an allocation unit, consistsof one or more sectors of storage space, andrepresents the minimum amount of space that an

operating system allocates when saving thecontents of a file to a disk.

The number of sectors per cluster is dependent on

Type of disk (floppy disk, hard disk)

Version of operating systems

Size of disk

Clusters?

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There are3versions of FAT: FAT-12, FAT-16, and FAT-32.These numbers refer to the number of bits available to

define clusters. The floppy disk were looking at uses FAT-12, and so is limited to 212 or approximately 4096clusters.

A cluster is made up of 4 sectors (the minimum size thatcan be allocated.)

A sector is 512bytes a Cluster is2048 bytes.So Fat-12 has a maximum of 4078 clusters *2048

bytes/cluster = 8 Megabytes

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FAT32 provides the following

enhancements over previousimplementations of the FAT file

system:FAT32 supports drives up to 2

terabytes in size.

FAT32 uses space more efficiently. It

uses smaller clusters (that is, 4-KB

clusters for drives up to 8 GB in

size), resulting in 10 to 15 percentmore efficient use of disk space

relative to large FAT or FAT16 drives.

Features ofFAT32

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FAT32 is more robust. FAT32can relocate the

root folder and use the backup copy of the fileallocation table instead of the default copy.

FAT32 is more flexible.The root folder on a

FAT32drive is an ordinary cluster chain, so itcan be located anywhere on the drive.Theprevious limitations on the number of root

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Advantages of FAT File System

The FAT file system is best for drives and/or partitionsunder approximately 200 MB

It is better to format system partition as FAT

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Disadvantage of FAT File System

It is not better to use FAT on partitions that aregreater than 200 megabytes. FAT partitions are

limited in size to a maximum of 4 Gigabytes (GB)under Windows NT and 2GB in MS-DOS.

The FAT file system is also prone to fragmentation

(its the inability of a file system to lay out relateddata sequentially (contiguously)

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NTFS

NTFS stand for new technology file system

It is the standard file system of Windows NT,including its later versions Windows

2000, Windows XP, Windows Server

2003, Windows Server 2008,Windows Vista,

and Windows 7.

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Advantages:

Improve performance: its much more efficientthan FAT

Reliability: NTFS uses a lossless compression

algorithm, which ensures that no data is lost

when compressing and decompressing data.

Security : Using NTFS permissions you can

control access to every file on an NTFS volume.

Using disk quotas enables you to control theamount of data that users can store on your

NTFS volumes

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Disadvantages of NTFS

It is not recommended to use NTFS on avolume that is smaller than approximately

400 MB Currently, there is no file encryption built

into NTFS It is not possible to format a floppy disk with

the NTFS file system

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Define Cluster Size Properly

Cluster is an allocation unit. If you create file lets

say 1 byte in size, at least one cluster should beallocated on FAT file system. On NTFS if file is

small enough, it can be stored in MFT record

itself without using additional clusters.

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DRIVE SIZEDRIVE SIZEFAT 16FAT 16

Cluster SizeCluster SizeFAT 32FAT 32

Cluster SizeCluster SizeNTFSNTFS

Cluster SizeCluster Size

260 to 511 MB260 to 511 MB 8 KB (16 sectors)8 KB (16 sectors) Not SupportedNot Supported 512 bytes (1512 bytes (1sector)sector)

512 to 1023 MB512 to 1023 MB 16 KB (32 sectors)16 KB (32 sectors) 4 KB (8 sectors)4 KB (8 sectors) 1KB (2 sectors)1KB (2 sectors)

1024 MB to 21024 MB to 2GBGB

32 KB (64 sectors)32 KB (64 sectors) 4 KB (8 sectors)4 KB (8 sectors) 2 KB (4 sectors)2 KB (4 sectors)

2 to 4 GB2 to 4 GB 64 KB (128 sectors)64 KB (128 sectors) 4 KB (8 sectors)4 KB (8 sectors) 4 KB (8 sectors)4 KB (8 sectors)

4 to 8 GB4 to 8 GB Not SupportedNot Supported 4 KB (8 sectors)4 KB (8 sectors) 8 KB (16 sectors)8 KB (16 sectors)

8 to 16 GB8 to 16 GB Not SupportedNot Supported 8 KB (16 sectors)8 KB (16 sectors) 16 KB (32 sectors)16 KB (32 sectors)

16 to 32 GB16 to 32 GB Not SupportedNot Supported 16 KB (32 sectors)16 KB (32 sectors) 32 KB ( 64 sectors)32 KB ( 64 sectors)

>32 GB>32 GB (up to 2 TB)(up to 2 TB) Not SupportedNot Supported 32 KB (64 sectors)32 KB (64 sectors) 64 KB (128 sectors)64 KB (128 sectors)

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FAT VS NTFS

Microsoft highly recommends you choose NTFS

If your hard drive is larger then 32GB, use NTFSfor best performance.

Your hard drive may not appear to be as big as it

really is when using FAT32; so when given a

choice, use NTFS.

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Conversionvolume from FAT to

NTFS

Converted file in NTFS is slower so we do

defragmentation Defragmentation tools are in general unable to

defragment MFT (Master FileTable ), however,

you can try to backup the whole system, re-

format the volume with proper cluster size, andrestore it back.

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Compare FATand NTFS File

System

Compatibility

Only Windows NT supports NTFS partitions , Windows NTand Windows 95 supports both NTFS and FAT

Volume size

FAT supports partition sizes only up to 2GB , the maximumsize of an NTFS partition is 16 EB

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FaulttoleranceWindows NT offers software support for several alternatedisk-access methods that increase speed and/or fault

tolerance, While FAT does maintain two copies of the file-

allocation table, in case one copy is damaged, its incapableof automatically fixing errors)

FilecompressionNTFS has its native support for file compression, It offers you

the chance to compress individual files and directories ofyour choice

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ThesystempartitionA better solution is to format your system partition

as FAT because NTFS partitions are accessible only viaWindows NT. If you have a fatal error with WindowsNT, you cant simply boot a system disk to a

command prompt and fix a problem on an NTFSpartition

Convertingto NTFSIn MS-DOS type command: CONVERT drive: /FS:NTFS

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THANK U