Ayseg

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Aysegül AYHAN Can KOÇOGLU
Operating Systems File
Systems
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OUTLINE

• What is the file system ?
• File systems under Unix and Unix - like systems
• ext2 (Linux)
• ext3(Linux)
• Reiser FS (Linux)
• File Systems under Mac OS X
• HFS - Hierachical File System
• HFS -Hierachical File System Plus
• File Systems under Microsoft Windows
• FAT 12- 16(File Allocation Table)
• FAT 32(File Allocation Table)
• NTFS(New Technology File System)
• Conclusion
• Compare of these file systems with tables

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What is file system?

• is a method for storing and organizing computer
  files
• make data easy to find and access them.

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File systems under Unix and Unix - like systems

• one root directory, and every file existing
  under it.
• programs, device drivers, documents and
  spreadsheets, keyboard, etc. are files in Unix.
• avoids becoming an ungainly mess.

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??? This is how it works.
An example from real life
???
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Linux is also an Unix-like Operating System

• ext 2
• ext 3
• reiser FS

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ext 2

• Previlages can be given to each of User, Group,
  Others.
• file system which proved itself
• Max file size 2 gb
• Max char size 255 chars
• Max volume size 4tb
• efficient if 4K blocks are used
• journal with ext3.
• Fullness of the disk not affects speed.

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ext3

• Almost same as ext2 but journal property added.
• So it is called journalled file system.

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Reiser FS

• journaling property
• Max file size 8 tb
• Max volume 16tb
• High performance
• Especially small files
• but not much healthy..

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File Systems under Mac OS X

• HFS Hierachical File System
• HFS Hierachical File System Plus

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HFSHierachical File System

• Similar MS-DOS and Unix with subdirectories
• Volume names max 27 chars.
• file names max 31 chars
• upper and lower case names unimportant
• All characters can be used, such as , ?, \
• has two forks data fork, resource fork ..

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HFS is developed version of HFS
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File systems under Microsoft Windows

• MS-DOS
• FAT 12 (File Allocation Table)
• FAT 16 (File Allocation Table)
• FAT 32 (File Allocation Table)
• NTFS(New Technology File System)

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MS DOS

• Only Intel platforms
• Not support multi-programming
• Version 1 only single directory
• Version 2- more directories (hierarchical)

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FAT 16 FILE ALLOCATION TABLE

• introduced way back with MSDOS
• to handle files floppy drive
• minor modifications over the years
• can handle hard disks, even file names longer
  than the original limitation.

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FAT 12

• First version of FAT system
• Max file size 32 MB
• File name size 255 MB
• Max valume size 32 MB

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FAT 16

• Advantages
• MS-DOS Unix and Windows accept
• Has saving succesfull program to resque folders
• Has inauguration floppy if computer is locked
• To accesing data fast partitions lt 256MB

• Disadvantages
• Max folder 65536.
• 4GB max size to folder
• doesn't support compression, encryption
• Lack of security

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FAT 32 FILE ALLOCATION TABLE

• enhanced version of the FAT
• used on drives from 512 megabytes (MB) to 2 TB
• partition limit is approximately 128GB
• can be accessed Win95B (OSR2, OSR2.1), Win95C
  (OSR2.5), Win98, Win98SE, WinME, Win2K and WinXP
• not accessed by DOS, Windows 3.x and Windows NT
  4.0
• majority of systems are formatted with FAT32 as
  the default.

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FAT 32

• Disadvantages
• much more slower directories has too many files
• Fragmantation performance
• Should disk fregmantation frequently
• hard to access big files
• One file size only 4GB.

• Advantages
• Acceptable all operating systems
• more efficient for 64 MB and less than 64 MB
  memory
• more faster if folder is small or not to big.
• Comparing to NTFS hard disk head moves
  less.Because of that it works more efficiently on
  slower hard disks.

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NTFSNew Technology File System

• introduced with first version of Windows NT
• completely different file system from FAT
• provides for greatly increased security,
  filebyfile compression, quotas, and even
  encryption

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NTFS

• Disadvantages
• not suggested for less
• than 64MB memory
• hard disk fast is low NTFS performance
  than FAT

• Advantages
• System performance does not effect
  disorganisation
• File size performance
• Small file --gtfast accessing

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Conclusion
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Comparison of File Systems

• Limits

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Comparison of File Systems

• Metadata

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Comparison of File Systems

• Features