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Presented to: Sir Ahmad Karim Presented by: Tahmina Gillani (MIT-08-13) Mehwish saba (MIT-08-03)...

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Presented to: Sir Ahmad Karim Presented by: Tahmina Gillani (MIT-08-13) Mehwish saba (MIT-08-03) Hira Nargis (MIT-08-19)
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Page 1: Presented to: Sir Ahmad Karim Presented by: Tahmina Gillani (MIT-08-13) Mehwish saba (MIT-08-03) Hira Nargis (MIT-08-19) Misbah Fatima (MIT-08-12) Ayesha.

Presented to: Sir Ahmad Karim

Presented by: Tahmina Gillani (MIT-08-13) Mehwish saba (MIT-08-03) Hira Nargis (MIT-08-19) Misbah Fatima (MIT-08-12) Ayesha Raee (MIT-08-04)

Page 2: Presented to: Sir Ahmad Karim Presented by: Tahmina Gillani (MIT-08-13) Mehwish saba (MIT-08-03) Hira Nargis (MIT-08-19) Misbah Fatima (MIT-08-12) Ayesha.

FILE SYSTEMS

Page 3: Presented to: Sir Ahmad Karim Presented by: Tahmina Gillani (MIT-08-13) Mehwish saba (MIT-08-03) Hira Nargis (MIT-08-19) Misbah Fatima (MIT-08-12) Ayesha.

File Names

1 to 255 characters in lengthThis includes the path

You can use uppercase and lowercase (case-aware, but not case-sensitive)

You can use spaces and periods You cannot use these characters:

/ \ : * ? “ < > |

Page 4: Presented to: Sir Ahmad Karim Presented by: Tahmina Gillani (MIT-08-13) Mehwish saba (MIT-08-03) Hira Nargis (MIT-08-19) Misbah Fatima (MIT-08-12) Ayesha.

File Names continued

Filenames consist of two parts Main part of filename

Identifies the contents of the file

File extension Identifies the file type

The last period separates the file extension from the main part of the filename.

Windows typically associates a file extension with an application installed on a computer

Page 5: Presented to: Sir Ahmad Karim Presented by: Tahmina Gillani (MIT-08-13) Mehwish saba (MIT-08-03) Hira Nargis (MIT-08-19) Misbah Fatima (MIT-08-12) Ayesha.

Folder Names

Folder names follow the same guidelines for naming files

Folder names usually do not have a file extension

Page 6: Presented to: Sir Ahmad Karim Presented by: Tahmina Gillani (MIT-08-13) Mehwish saba (MIT-08-03) Hira Nargis (MIT-08-19) Misbah Fatima (MIT-08-12) Ayesha.

MS-DOS filename

Filename: 1 to 8 characters File extension: 1 to 3 characters DOS only uses uppercase You cannot use spaces A single period separates the file extension from

the filename You cannot use these characters:

/ \ : * ? “ < > | + = ; , [ ]

Page 7: Presented to: Sir Ahmad Karim Presented by: Tahmina Gillani (MIT-08-13) Mehwish saba (MIT-08-03) Hira Nargis (MIT-08-19) Misbah Fatima (MIT-08-12) Ayesha.

The Full Path

What does it mean?The complete path from the root of the files

system to the desired object.

Use \ (vs. /)C:\ - the root

C:\documents and settings\theresa\octc\cis110\filesystems.ppt

Page 8: Presented to: Sir Ahmad Karim Presented by: Tahmina Gillani (MIT-08-13) Mehwish saba (MIT-08-03) Hira Nargis (MIT-08-19) Misbah Fatima (MIT-08-12) Ayesha.

File Systems

A file system defines the structure and the rules used to read, write, and maintain information stored on a disk.

Which system used is determined by;HardwareSoftwareSecurity needsNeed for a dual-booting system

Page 9: Presented to: Sir Ahmad Karim Presented by: Tahmina Gillani (MIT-08-13) Mehwish saba (MIT-08-03) Hira Nargis (MIT-08-19) Misbah Fatima (MIT-08-12) Ayesha.

FAT???

file allocation table – where the OS records how the disk space is used

Page 10: Presented to: Sir Ahmad Karim Presented by: Tahmina Gillani (MIT-08-13) Mehwish saba (MIT-08-03) Hira Nargis (MIT-08-19) Misbah Fatima (MIT-08-12) Ayesha.

File Systems FAT 16 – oldest, created for DOS, supported by

most OSs’, cannot be installed on partitions larger than 2 GB, or on hard drives larger than 4GB.

FAT 32 – supports disks from 512 to 2TB, compatible with Windows 98 and up

NTFS – (new technology file system) – better file security (Encrypting File System), disk compression, logging features, reliability and stability. NTFS volumes can not be accessed by DOS, or Windows 95 or Windows 98.

Page 11: Presented to: Sir Ahmad Karim Presented by: Tahmina Gillani (MIT-08-13) Mehwish saba (MIT-08-03) Hira Nargis (MIT-08-19) Misbah Fatima (MIT-08-12) Ayesha.

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 bySize of the hard driveFile allocation system – FAT, FAT32, NTFS

Page 12: Presented to: Sir Ahmad Karim Presented by: Tahmina Gillani (MIT-08-13) Mehwish saba (MIT-08-03) Hira Nargis (MIT-08-19) Misbah Fatima (MIT-08-12) Ayesha.

Tracks

Sectors within a

Track

Cluster

Page 13: Presented to: Sir Ahmad Karim Presented by: Tahmina Gillani (MIT-08-13) Mehwish saba (MIT-08-03) Hira Nargis (MIT-08-19) Misbah Fatima (MIT-08-12) Ayesha.

A hard disk has extremely smooth metal or glass plates called “platters” (vs. the floppy mylar disk of a floppy disk).

Each platter is divided into tracks and sectors by the format operation, like a floppy disk, however the number of tracks and sectors is different. The number of tracks on a hard disk depends on the disk size and the manufacturer.

Page 14: Presented to: Sir Ahmad Karim Presented by: Tahmina Gillani (MIT-08-13) Mehwish saba (MIT-08-03) Hira Nargis (MIT-08-19) Misbah Fatima (MIT-08-12) Ayesha.

A cluster, also known as an allocation unit, consists of one or more sectors of storage space, and represents the minimum amount of space that an operating system allocates when saving the contents 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

Every sector contains 512 bytes. (NTFS does allow you to change this number.)

The number of clusters per disk is determined by the filing system (FAT 16, FAT 32 or NTFS).

Clusters?

Page 15: Presented to: Sir Ahmad Karim Presented by: Tahmina Gillani (MIT-08-13) Mehwish saba (MIT-08-03) Hira Nargis (MIT-08-19) Misbah Fatima (MIT-08-12) Ayesha.

DRIVE SIZEFAT 16

Cluster SizeFAT 32

Cluster SizeNTFS

Cluster Size

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

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

1024 MB to 2 GB 32 KB (64 sectors) 4 KB (8 sectors) 2 KB (4 sectors)

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

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

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

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

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

Page 16: Presented to: Sir Ahmad Karim Presented by: Tahmina Gillani (MIT-08-13) Mehwish saba (MIT-08-03) Hira Nargis (MIT-08-19) Misbah Fatima (MIT-08-12) Ayesha.

So, what does this all mean to us, as Windows XP users?

The bigger your disk – the bigger your clusters (because there is a maximum number of clusters per disk).

One way to help alleviate the problem of slack space is to partition the hard drive into smaller “drives”. Reducing the drive size will reduce the cluster size.

Page 17: Presented to: Sir Ahmad Karim Presented by: Tahmina Gillani (MIT-08-13) Mehwish saba (MIT-08-03) Hira Nargis (MIT-08-19) Misbah Fatima (MIT-08-12) Ayesha.

Which file system should you use?

If your computer runs only Windows XP and you do not plan to install other OS, use NTFS

However if you want to use other OS and you want to access the volumes you must use FAT16 or FAT32

Page 18: Presented to: Sir Ahmad Karim Presented by: Tahmina Gillani (MIT-08-13) Mehwish saba (MIT-08-03) Hira Nargis (MIT-08-19) Misbah Fatima (MIT-08-12) Ayesha.

OS and File System Compatibility

Operating System FAT16 FAT32 NTFS

Windows XP

Windows 2000

Windows NT

Windows 95, 98, ME

Windows 95

MS-DOS

Page 19: Presented to: Sir Ahmad Karim Presented by: Tahmina Gillani (MIT-08-13) Mehwish saba (MIT-08-03) Hira Nargis (MIT-08-19) Misbah Fatima (MIT-08-12) Ayesha.

What happens during the Formatting Process?

OS creates four tables in the 1st sectorsBoot Record – the name & version number of the OS, info. Master File Table #1- keeps track of

Available clustersClusters that contain dataClusters that are defectiveClusters that contain OS files

Master File Table #2 – copy of MFT #1Directory Table – top level folder and file information

Page 20: Presented to: Sir Ahmad Karim Presented by: Tahmina Gillani (MIT-08-13) Mehwish saba (MIT-08-03) Hira Nargis (MIT-08-19) Misbah Fatima (MIT-08-12) Ayesha.

Formatting Process, cont.

Full Format lays down new tracks and sectorsVerifies the integrity of each sector

By doing a surface scan – OS will put dummy data into sectors and then try to read the sector

Quick FormatRemoves filesDoes not check for defective sectors

Page 21: Presented to: Sir Ahmad Karim Presented by: Tahmina Gillani (MIT-08-13) Mehwish saba (MIT-08-03) Hira Nargis (MIT-08-19) Misbah Fatima (MIT-08-12) Ayesha.

Ext 3

Ext 3(third extended file system): Journaled file system used by Linux kernel. Introduced November 2001(Linux 2.4.15) Enhanced form of Ext 2 which Improve reliability Eliminates the need to check the file

system after an unclean shut down.

Page 22: Presented to: Sir Ahmad Karim Presented by: Tahmina Gillani (MIT-08-13) Mehwish saba (MIT-08-03) Hira Nargis (MIT-08-19) Misbah Fatima (MIT-08-12) Ayesha.

Advantages

Back up and restore data Less CPU power than other file systems in

Linux like XFS. More safer due to its relative simplicity and

wider testing base.

Page 23: Presented to: Sir Ahmad Karim Presented by: Tahmina Gillani (MIT-08-13) Mehwish saba (MIT-08-03) Hira Nargis (MIT-08-19) Misbah Fatima (MIT-08-12) Ayesha.

Cont’d

The ext3 file system adds, over its predecessor:

A journaling file system. Online file system growth. Htree indexing for larger directries.

Page 24: Presented to: Sir Ahmad Karim Presented by: Tahmina Gillani (MIT-08-13) Mehwish saba (MIT-08-03) Hira Nargis (MIT-08-19) Misbah Fatima (MIT-08-12) Ayesha.

Cont’d

Size limits: Maximum size for both indiviual files and

entire file systems. Max file size 16 GB – 2 TB. Max number of files:Variable,Allocated at

creation time. Max file name length:254 Bytes.

Page 25: Presented to: Sir Ahmad Karim Presented by: Tahmina Gillani (MIT-08-13) Mehwish saba (MIT-08-03) Hira Nargis (MIT-08-19) Misbah Fatima (MIT-08-12) Ayesha.

Journalling levels

Three levels in Linux implementation of Ext 3:

Journal(lowest risk) Ordered(medium risk) Writeback(highest risk)

Page 26: Presented to: Sir Ahmad Karim Presented by: Tahmina Gillani (MIT-08-13) Mehwish saba (MIT-08-03) Hira Nargis (MIT-08-19) Misbah Fatima (MIT-08-12) Ayesha.

Disadvantages

Functionality Defregmentation Recovery Compression NO checksumming in journal

Page 27: Presented to: Sir Ahmad Karim Presented by: Tahmina Gillani (MIT-08-13) Mehwish saba (MIT-08-03) Hira Nargis (MIT-08-19) Misbah Fatima (MIT-08-12) Ayesha.

Thanks for your

kind presence


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