1. PRESENTATION ON
FILE SYSTEM
BY :- SHIVNEEP KAUR

2. WHAT IS FILE ?
A file is a collection of related information that is recorded on
secondary storage. Or file is a collection of logically related
entities. From user’s perspective a file is the smallest allotment
of logical secondary storage.
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3. WHAT IS FILE SYSTEM?
In computing, a file system or filesystem is used to control how data
is stored and retrieved. Without a file system, information placed in a
storage medium would be one large body of data with no way to tell
where one piece of information stops and the next begins. By
separating the data into pieces and giving each piece a name, the
information is easily isolated and identified.
Common file systems in use include the UNIX file system, UFS, the
Berkeley Fast File System, FFS, Windows systems FAT, FAT32, NTFS,
CD-ROM systems ISO 9660, and for Linux the extended file systems
ext2 and ext3
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4. DIFFERENCE BETWEEN FAT32, EXFAT, AND NTFS
FILE SYSTEM
• A file system provides a way of organizing a drive. It specifies how data is stored
on the drive and what types of information can be attached to files—filenames,
permissions, and other attributes.
• Windows supports three different file systems which are NTFS,FAT32 and exFAT.
• NTFS is the most modern file system. Windows uses NTFS for its system drive
and, by default, for most non-removable drives.
• FAT32 is an older file system that’s not as efficient as NTFS and doesn’t support
as big a feature set, but does offer greater compatibility with other operating
systems.
• exFAT is a modern replacement for FAT32 and more devices and operating
systems support it than NTFS but it’s not nearly as widespread as FAT32.
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5. NT FILE SYSTEM (NTFS)
• NTFS is the modern file system Windows likes to use by default. When you install Windows, it
formats your system drive with the NTFS file system. NTFS has file size and partition size limits
that are so theoretically huge you won’t run up against them.
• NTFS first appeared in consumer versions of Windows with Windows XP, though it originally
debuted with Windows NT.
• NTFS is packed with modern features which are not available on FAT32 and exFAT. NTFS
supports file permissions for security, a change journal that can help quickly recover errors if
your computer crashes, shadow copies for backups, encryption, disk quota limits, hard links,
and various other features.
• Compatibility : Works with all versions of Windows, but read-only with Mac by default, and may
be read-only by default with some Linux distributions.
• Limitations : No realistic file-size or partition size limits.
• Ideal Usage : Use it for your Windows system drive and other internal drives that will just be
used with Windows.
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6. FILE ALLOCATION TABLE 32 (FAT32)
• FAT32 is the oldest of the three file systems available to Windows. It was introduced
all the way back in Windows 95 to replace the older FAT16 file system used in MS-
DOS and Windows 3.
• Individual files on a FAT32 drive can’t be over 4 GB in size—that’s the maximum. A
FAT32 partition must also be less than 8 TB, which admittedly is less of a limitation
unless you’re using super-high-capacity drives.
• Modern versions of Windows can no longer be installed to a drive formatted with
FAT32; they must be installed to drives formatted with NTFS.
• Compatibility : Works with all versions of Windows, Mac, Linux, game consoles, and
practically anything with a USB port.
• Limitations : 4 GB maximum file size, 8 TB maximum partition size.
• Ideal Usage : Use it on removable drives where you need maximum compatibility
with the widest range of devices, assuming you don’t have any files 4 GB or larger in
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7. EXTENDED FILE ALLOCATION TABLE
(EXFAT)
• The exFAT file system was introduced in 2006 and was added to older
versions of Windows with updates to Windows XP and Windows Vista.
• exFAT is optimized for flash drives—designed to be a lightweight file system
like FAT32, but without the extra features and over head of NTFS and without
the limitations of FAT32.
• exFAT has very large limits on file and partition sizes., allowing you to store
files much larger than the 4 GB allowed by FAT32.
• Compatibility : Works with all versions of Windows and modern versions of
Mac OS X, but requires additional software on Linux. More devices support
exFAT than support NTFS.
• Limitations : No realistic file-size or partition-size limits.
• Ideal Usage : Use it when you need bigger file size and partition limits than
FAT32 offers and when you need more compatibility than NTFS offers.
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8. WHY WE NEED FILE SYSTEM?
A file system is the methods and data structures that an
operating system uses to keep track of files on a disk or
partition; that is, the way the files are organized on the disk. The
word is also used to refer to a partition or disk that is used to
store the files
The most important purpose of a file system is to manage user
data. This includes storing, retrieving and updating data.
Some file systems accept data for storage as a stream of bytes
which are collected and stored in a manner efficient for the
media.
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9. FILE TYPES/ATTRIBUTES:
ATTRIBUTES TYPES OPERATIONS
Name Doc Create
Type Exe Open
Size Jpg Read
Creation Data Xis Write
Author C Append
Last Modified Java Truncate
protection class Delete
Close
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10. FILE TYPE USUAL EXTENSION FUNCTION
Executable exe, com, bin
Read to run
machine language
program
Object obj, o
Compiled,
machine language
not linked
Source Code
C, java, pas, asm,
a
Source code in
various languages
Batch bat, sh
Commands to the
command
interpreter
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11. Text txt, doc
Textual data,
documents
Word
Processor
wp, tex, rrf,
doc
Various word
processor
formats
Archive arc, zip, tar
Related files
grouped into
one
compressed
file
Multimedia
mpeg, mov,
rm
For
containing
audio/video
information
FILE TYPE USUAL EXTENSION FUNCTION
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12. FILE DIRECTORIES
Collection of files is a file directory. The directory contains
information about the files, including attributes, location and
ownership. Much of this information, especially that is concerned
with storage, is managed by the operating system. The directory
is itself a file, accessible by various file management routines
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14. INFORMATION CONTAINED IN A DEVICE
DIRECTORY ARE:
• Name
• Type
• Address
• Current length
• Maximum length
• Date last accessed
• Date last updated
• Owner id
• Protection information
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15. OPERATION PERFORMED ON DIRECTORY
ARE:
• Search for a file
• Create a file
• Delete a file
• List a directory
• Rename a file
• Traverse the file system
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16. ADVANTAGES OF MAINTAINING
DIRECTORIES ARE:
• Efficiency: A file can be located more quickly.
• Naming: It becomes convenient for users as two users can have
same name for different files or may have different name for
same file.
• Grouping: Logical grouping of files can be done by properties
e.g. all java programs, all games etc.
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17. SINGLE-LEVEL DIRECTORY
• In this a single directory is maintained for all the users.
• Naming problem: Users cannot have same name for two files.
• Grouping problem: Users cannot group files according to their
need
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19. TWO-LEVEL DIRECTORY:
• In this separate directories for each user is maintained.
• Path name:Due to two levels there is a path name for every file
to locate that file.
• Now,we can have same file name for different user.
• Searching is efficient in this method.
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21. TREE-STRUCTURED DIRECTORY :
Directory is maintained in the form of a tree. Searching is
efficient and also there is grouping capability. We have absolute
or relative path name for a file.
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23. FILE ALLOCATION METHODS
1. Continuous Allocation: A single continuous set of blocks is allocated
to a file at the time of file creation. Thus, this is a pre-allocation
strategy, using variable size portions. The file allocation table needs just
a single entry for each file, showing the starting block and the length of
the file. This method is best from the point of view of the individual
sequential file. Multiple blocks can be read in at a time to improve I/O
performance for sequential processing. It is also easy to retrieve a single
block. For example, if a file starts at block b, and the ith block of the file
is wanted, its location on secondary storage is simply b+i-1.
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24. 2. Linked Allocation(Non-contiguous allocation) : Allocation is on
an individual block basis. Each block contains a pointer to the
next block in the chain. Again the file table needs just a single
entry for each file, showing the starting block and the length of
the file. Although pre-allocation is possible, it is more common
simply to allocate blocks as needed. Any free block can be added
to the chain. The blocks need not be continuous. Increase in file
size is always possible if free disk block is available. There is no
external fragmentation because only one block at a time is
needed but there can be internal fragmentation but it exists only
in the last disk block of file.
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25. FILE SHARING:
• File sharing is the practice of sharing or offering access to digital information or
resources, including documents, multimedia (audio/video), graphics, computer programs,
images and e-books. It is the private or public distribution of data or resources in a
network with different levels of sharing privileges.
File sharing can be done using several methods. The most common techniques for file
storage, distribution and transmission include the following:
• Removable storage devices
• Centralized file hosting server installations on networks
• World Wide Web-oriented hyperlinked documents
• Distributed peer-to-peer networks
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26. PHYSICAL FILE
•
1. Occupies the portion of memory. It contains the original data.
2. A physical file contains one record format
3.Can exist even without LF
4. If there is a logical file for a PF, the PF can’t be deleted until and unless
we delete the LF.
5.CRTPF command is used to create such object
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27. LOGICAL FILE
•
1. Does not occupy any memory space. Does not contain any data. It loads
itself at run time as per the defined access path.
2. A logical file can contain up to 32 record formats.
3. Can’t exist without PF
4. If there is a logical file for a PF, the LF can be deleted without deleting
the PF.
5.CRTLF command is used to create such type object
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28. THANK YOU FOR LISTENING.
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