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FINAL PRESENTATION
OPERATING SYSTEM
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Nabeela Yaqoob
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Taimoor Muneeb Huzaifa Ubaid
File System File Concept Memory Mapped Thrashing
File
Table Of Content
File System 01
File Concept
02
Memory Mapped File 03
Thrashing 04
File System
File system is a module of OS
Manages Data
Permanent Data Storage
EXAMPLES
Windows - NTFS
Docs - FAT
UNIX - FS
LINUX - Extended File System
Functionality
Data is stored in disk
Data is divided into blocks
Blocks are divided into sectors randomly
File system manage this mapping
Data can be store easily
Data can be fetched easily
Disk contain platters-surfaces-tracks
Project Stage
FOLDER/ FILE
USER FILE DIRECTORY SYSTEM
Create Stored Managed by
File concept
The operating system can provide a logical
view of the information stored in the disks, this
logical unit is known as a file. The information
stored in files is not lost during power failures.
A file helps to write data on the computer. It is
a sequence of bits, bytes, or records, the
structure of which is defined by the owner and
depends on the type of the file.
Different types of files are:
Executable file Source file Text file Image file
In an executable file, he source file has A text file is a An image file is a
the binary code that is subroutines and sequence of sequence of visual
loaded in the memory functions that are characters. information, for
for execution is compiled later. example, vector art.
stored. It is stored in
an exe type file.
Different types of files Extensions
File Attributes
Some of the common file attributes are:
1. Only the user can edit the name they have assigned to a file.
2. A unique number tag is given to every file. It cannot be read by the
user and is used by the file system to identify the file.
3. The time, date, and user identification are maintained to access the
information about which date the file was created, edited, or last
accessed.
4. The type of the file is easily identified.
5. The size of the file in bits, bytes, or Kilobytes.
6. Access control can be defined by the user, as to who can access the
files to read, write, edit or delete the information stored in them.
Memory mapped files
Memory-mapped files (MMFs) are a mechanism that allows
applications to map a file's contents into the virtual memory space of
a process. This technique provides a way to manipulate file data as if
it were part of the process's own address space, enabling efficient
file I/O operations and inter-process communication (IPC).
Basic Mechanism of
Memory Mapped
1. A page-sized portion of the file is read from the file system into a
physical page.
2. Manipulating the files through the use of memory rather than
incurring the overhead of using the read() and write() system calls
not only simplifies but also speeds up file access and usage.
3. Multiple processes may be allowed to map a single file
simultaneously to allow sharing of data.
4. If any of the processes write data in the virtual memory, then the
modified data will be visible to all the processes that map the
same section of the file.
Memory Mapping
Thrashing
Thrashing in os is a phenomenon that occurs in computer operating
systems when the system spends an excessive amount of time
swapping data between physical memory (RAM) and virtual memory
(disk storage) due to high memory demand and low available
resources. It can result in severe performance degradation, as the
system spends more time swapping data than executing programs.
Symptoms and How
to Detect it?
High Disk Activity: When the system is Thrashing in os, the disk activity
increases significantly as the system tries to swap data between physical
memory and virtual memory. This can be observed by monitoring disk
usage using system monitoring tools.
Slow Response Time: When the system is Thrashing in os, its response
time slows significantly as the CPU spends most of its time swapping
data between physical and virtual memory. This can be observed by
measuring the response time of system processes and applications.
High CPU Utilization: When the system is Thrashing in os, the CPU
utilization increases significantly as it spends most of its time swapping
data between physical and virtual memory. This can be observed by
monitoring CPU usage using system monitoring tools.
Thank You!
