The kernel manages processes, memory, and I/O. It has two levels - user level and kernel level. Processes interact with the kernel through system calls. A process contains text, data, stack, and a U area. The kernel uses process tables, region tables, and context switches to manage multiple simultaneous processes. The file system contains boot blocks, super blocks, inode lists, and data blocks to organize files on disk. Processes can create new processes using the fork system call.
A presentation on layered software architecture that goes through logical layering and physical layering, the difference between those two and a practical example.
Apresentação do trabalho da Disciplina de Paradigmas de Linguagens de Programação do ILES/ULBRA - 3º Período - 2011/1 - Grupo: Guilherme Abdala e Tibor. Tema: Linguagem Plankalkül.
A presentation on layered software architecture that goes through logical layering and physical layering, the difference between those two and a practical example.
Apresentação do trabalho da Disciplina de Paradigmas de Linguagens de Programação do ILES/ULBRA - 3º Período - 2011/1 - Grupo: Guilherme Abdala e Tibor. Tema: Linguagem Plankalkül.
Topic: I/O Buffering in Operting System
Discussion Points:
-Why we need buffering?
-Problems in buffering
-Types of I/O Devices
-Types of Buffer
-Types of approaches to buffering
-Which type of buffer is used with which type of I/O device and how?
Deadlock is a very important topic in operating system. In this presentation slide, try to relate deadlock with real life scenario and find out some solution with two main algorithm- Safety and Banker's Algorithm.
Evaluation of morden computer & system attributes in ACAPankaj Kumar Jain
Elements of Modern Computers, Architectural
Evolution in computer architecture ,System Attributes to Performance,Clock Rate and CPI,MIPS Rate,Throughput Rate,Implicit Parallelism,Explicit Parallelism, State of computing,
INTRODUCTIONTO OPERATING SYSTEM
What is an Operating System?
Mainframe Systems
Desktop Systems
Multiprocessor Systems
Distributed Systems
Clustered System
Real -Time Systems
Handheld Systems
Computing Environments
In this presentation, I am explaining about Threads, types of threads, its advantages and disadvantages, difference between Process and Threads, multithreading and its type.
"Like the ppt if you liked the ppt"
LinkedIn - https://in.linkedin.com/in/prakharmaurya
It consists of CPU scheduling algorithms, examples, scheduling problems, realtime scheduling algorithms and issues. Multiprocessing and multicore scheduling.
What is a Kernel? : Introduction And Architecturepec2013
An Assembly car that has all stuffs except exteriors.This assembly is responsible for the movement of car and various other functions but we cannot travel in it as it has no seats or exteriors.
This assembly is analogous to kernel. Without it operating system is nothing. More formally, we can also call kernel a type of micro OS that handles all the very important functions.
While the main OS contains various other functions and kernel in the same way the car has shafts and tyres for rotations.
Topic: I/O Buffering in Operting System
Discussion Points:
-Why we need buffering?
-Problems in buffering
-Types of I/O Devices
-Types of Buffer
-Types of approaches to buffering
-Which type of buffer is used with which type of I/O device and how?
Deadlock is a very important topic in operating system. In this presentation slide, try to relate deadlock with real life scenario and find out some solution with two main algorithm- Safety and Banker's Algorithm.
Evaluation of morden computer & system attributes in ACAPankaj Kumar Jain
Elements of Modern Computers, Architectural
Evolution in computer architecture ,System Attributes to Performance,Clock Rate and CPI,MIPS Rate,Throughput Rate,Implicit Parallelism,Explicit Parallelism, State of computing,
INTRODUCTIONTO OPERATING SYSTEM
What is an Operating System?
Mainframe Systems
Desktop Systems
Multiprocessor Systems
Distributed Systems
Clustered System
Real -Time Systems
Handheld Systems
Computing Environments
In this presentation, I am explaining about Threads, types of threads, its advantages and disadvantages, difference between Process and Threads, multithreading and its type.
"Like the ppt if you liked the ppt"
LinkedIn - https://in.linkedin.com/in/prakharmaurya
It consists of CPU scheduling algorithms, examples, scheduling problems, realtime scheduling algorithms and issues. Multiprocessing and multicore scheduling.
What is a Kernel? : Introduction And Architecturepec2013
An Assembly car that has all stuffs except exteriors.This assembly is responsible for the movement of car and various other functions but we cannot travel in it as it has no seats or exteriors.
This assembly is analogous to kernel. Without it operating system is nothing. More formally, we can also call kernel a type of micro OS that handles all the very important functions.
While the main OS contains various other functions and kernel in the same way the car has shafts and tyres for rotations.
Overview of the Linux Kernel, based on "Anatomy of the Linux Kernel" by M. Tim Jones, (IBM Developerworks) http://www.ibm.com/developerworks/linux/library/l-linux-kernel/
The kernel is the central module of an operating system (OS). It is the part of the operating system that loads first, and it remains in main memory. Because it stays in memory, it is important for the kernel to be as small as possible while still providing all the essential services required by other parts of the operating system and applications. The the kernel code is usually loaded into a protected area of memory to prevent it from being overwritten by programs or other parts of the operating system.
Typically, the kernel is responsible for memory management, process and task management, and disk management. The kernel connects the system hardware to the application software. Every operating system has a kernel.
in this presentation we cover Intro to Unix OS, its features and it management system like Process Management , file management and memory management system and its comparison with windows.
This presentation covers the understanding of system calls for various resource management and covers system calls for file management in details. The understanding of using system calls helps to start with working with device driver programming on Unix/Linux OS.
Honest Reviews of Tim Han LMA Course Program.pptxtimhan337
Personal development courses are widely available today, with each one promising life-changing outcomes. Tim Han’s Life Mastery Achievers (LMA) Course has drawn a lot of interest. In addition to offering my frank assessment of Success Insider’s LMA Course, this piece examines the course’s effects via a variety of Tim Han LMA course reviews and Success Insider comments.
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
Acetabularia Information For Class 9 .docxvaibhavrinwa19
Acetabularia acetabulum is a single-celled green alga that in its vegetative state is morphologically differentiated into a basal rhizoid and an axially elongated stalk, which bears whorls of branching hairs. The single diploid nucleus resides in the rhizoid.
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
Biological screening of herbal drugs: Introduction and Need for
Phyto-Pharmacological Screening, New Strategies for evaluating
Natural Products, In vitro evaluation techniques for Antioxidants, Antimicrobial and Anticancer drugs. In vivo evaluation techniques
for Anti-inflammatory, Antiulcer, Anticancer, Wound healing, Antidiabetic, Hepatoprotective, Cardio protective, Diuretics and
Antifertility, Toxicity studies as per OECD guidelines
1. Introduction to Kernel
Topics
– Kernel Architecture
– File System
– Process
Reference:
The Design of the UNIX Operating System
by Maurice J. Bach
2. kernel Architecture (UNIX)
Library
hardware
File Subsystem
character block
Hardware control
Buffer Cache
system call interface
Device driver
Inter process
communication
Scheduler
Memory
Managemen
t
Process Control
Subsystem
User program
User level
kernel level
User level
kernel level
3. File System
• A file system is consists of a sequence of logical blocks
(512/1024 byte etc.)
• A file system has the following structure:
Boot Block Super Block Inode List Data Blocks
4. File System: Boot Block
• The beginning of the file system
• Contains bootstrap code to load the operating
system
• Initialize the operating system
• Typically occupies the first sector of the disk
5. File System: Super Block
• Describes the state of a file system
• Describes the size of the file system
– How many files it can store
• Where to find free space on the file system
• Other information
6. File System: Inode List
• Inodes are used to access disk files.
• Inodes maps the disk files
• For each file there is an inode entry in the inode
list block
• Inode list also keeps track of directory structure
7. File System: Data Block
• Starts at the end of the inode list
• Contains disk files
• An allocated data block can belong to one and
only one file in the file system
8. Processes(1)
• A process is the execution of a program
• A process is consists of text (machine code), data and stack
• Many process can run simultaneously as kernel schedules
them for execution
• Several processes may be instances of one program
• A process reads and writes its data and stack sections, but it
cannot read or write the data and stack of other processes
• A process communicates with other processes and the rest
of the world via system calls
9. Processes(2)
• Kernel has a process table that keeps tract of all
active processes
• Each entry in the process table contains pointers to
the text, data, stack and the U Area of a process.
• All processes in UNIX system, except the very first
process (process 0) which is created by the system
boot code, are created by the fork system call
10. Kernel Support for Process
Text
Stack
DataFile Descriptor Table
Per Process Region Table
Kernel Process
Table
Kernel Region
TableA Process
U Area
11. Process: Region Table
• Region table entries describes the attributes of
the region, such as whether it contains text or
data, whether it is shared or private
• The extra level from the per process region table
to kernel region table allows independent
processes to share regions.
12. Process: U Area
• U Area is the extension of process table entry.
• Fields of process table entry:
– State field
– User ID (UID)
• Fields of U Area
– Pointer to process table entry
– File descriptors of all open files
– Current directory and current root
– I/O parameters
– Process and file size limit
• Kernel can directly access fields of the U Area of the
executing process but not of the U Area of other processes
13. Process Context
• The context of a process is its state:
– Text, data( variable), register
– Process region table, U Area,
– User stack and kernel stack
• When executing a process, the system is said to
be executing in the context of the process.
14. Context Switch
• When the kernel decides that it should execute
another process, it does a context switch, so that
the system executes in the context of the other
process
• When doing a context switch, the kernel saves
enough information so that it can later switch
back to the first process and resume its
execution.
15. Mode of Process Execution(1)
• The UNIX process runs in two modes:
– User mode
• Can access its own instructions and data, but not kernel
instruction and data
– Kernel mode
• Can access kernel and user instructions and data
• When a process executes a system call, the
execution mode of the process changes from
user mode to kernel mode
16. Mode of Process Execution(2)
• When moving from user to kernel mode, the
kernel saves enough information so that it can
later return to user mode and continue execution
from where it left off.
• Mode change is not a context switch, just
change in mode.
17. Process States
Process states are:
– The process is running in user mode
– The process is running in kernel mode
– The process is not executing, but it is ready to run as
soon as the scheduler chooses it
– The process is sleeping
• Such as waiting for I/O to complete
18. Process State Transition(1)
2
4
1
3asleep
user running
kernel running
ready to run
system call
or interrupt
Interrupt return
schedule processsleep
wakeup
return
context switch
permissible
19. Process State Transition(2)
• The kernel allows a context switch only when a
process moves from the state kernel running to
the state asleep
• Process running in kernel mode cannot be
preempted by other processes.
20. Fork System Call(1)
• When a process is created by fork, it contains
duplicate copies of the text, data and stack
segments of its parent
• Also it has a File Descriptor Table (FDT) that
contains references to the same opened files as
its parent, such that they both share the same
file pointer to each opened file
21. Fork System Call(2)
U Area
U Area
stack
data
text
stack
data
Kernel File
Table
Kernel Region
Table
Parent
Child
Region
table
Region
table