Download Operating System: An In-depth Study - Knowledge Gate Website and more Study notes Computer science in PDF only on Docsity!
Knowledge Gate Website
Syllabus(Semester Exam)
Unit – I Introduction : Operating system and functions, Classification of Operating systems- Batch, Interactive, Time sharing, Real Time System, Multiprocessor Systems, Multiuser Systems, Multiprocess Systems, Multithreaded Systems, Operating System Structure- Layered structure, System Components, Operating System services, Reentrant Kernels, Monolithic and Microkernel Systems. Unit – II CPU Scheduling: Scheduling Concepts, Performance Criteria, Process States, Process Transition Diagram, Schedulers, Process Control Block (PCB), Process address space, Process identification information, Threads and their management, Scheduling Algorithms, Multiprocessor Scheduling. Deadlock: System model, Deadlock characterization, Prevention, Avoidance and detection, Recovery from deadlock. Unit – III Concurrent Processes: Process Concept, Principle of Concurrency, Producer / Consumer Problem, Mutual Exclusion, Critical Section Problem, Dekker’s solution, Peterson’s solution, Semaphores, Test and Set operation; Classical Problem in Concurrency- Dining Philosopher Problem, Sleeping Barber Problem; Inter Process Communication models and Schemes, Process generation. Unit – IV Memory Management: Basic bare machine, Resident monitor, Multiprogramming with fixed partitions, Multiprogramming with variable partitions, Protection schemes, Paging, Segmentation, Paged segmentation, Virtual memory concepts, Demand paging, Performance of demand paging, Page replacement algorithms, Thrashing, Cache memory organization, Locality of reference. Unit – V I/O Management and Disk Scheduling: I/O devices, and I/O subsystems, I/O buffering, Disk storage and disk scheduling, RAID. File System: File concept, File organization and access mechanism, File directories, and File sharing, File system implementation issues, File system protection and security.
Chapters of This Video
(Chapter-1: Introduction) - Operating system, Goal & functions, System Components, Operating System services, Classification of Operating systems- Batch, Interactive, Multiprogramming, Multiuser Systems, Time sharing, Multiprocessor Systems, Real Time System. (Chapter-2: Operating System Structure) - Layered structure, Monolithic and Microkernel Systems, Interface, System Call. Chapter-3: Process Basics) - Process Control Block (PCB), Process identification information , Process States, Process Transition Diagram, Schedulers, CPU Bound and i/o Bound, Context Switch. (Chapter-4: CPU Scheduling)- Scheduling Performance Criteria, Scheduling Algorithms. (Chapter-5: Process Synchronization)- Race Condition, Critical Section Problem, Mutual Exclusion,, Dekker’s solution, Peterson’s solution, Process Concept, Principle of Concurrency, (Chapter-6: Semaphores) - Classical Problem in Concurrency- Producer/Consumer Problem, Reader-Writer Problem, Dining Philosopher Problem, Sleeping Barber Problem, Test and Set operation. (Chapter-7: Deadlock) - System model, Deadlock characterization, Prevention, Avoidance and detection, Recovery from deadlock. (Chapter-8)- Fork Command, Multithreaded Systems, Threads and their management (Chapter-9: Memory Management)- Memory Hierarchy, Locality of reference, Multiprogramming with fixed partitions, Multiprogramming with variable partitions, Protection schemes, Paging, Segmentation, Paged segmentation. (Chapter-10: Virtual memory) - Demand paging, Performance of demand paging, Page replacement algorithms, Thrashing. Chapter-11: Disk Management)- Disk Basics, Disk storage and disk scheduling, Total Transfer time. (Chapter-12: File System)- File allocation Methods, Free-space Management, File organization and access mechanism, File directories, and File sharing, File system implementation issues, File system protection and security.
What is Operating System
2. Resource Manager/Allocator – Operating system controls and coordinates the
use of system resources among various application programs in an unbiased
fashion.
What is Operating System
3. Platform - OS provides platform on which other application programs can be
installed, provides the environment within which programs are executed.
Goals and Functions of operating system
- Goals are the ultimate destination, but we follow functions to implement goals. सबका साथ सबका विकास
Goals of operating system
1. Primary goals (Convenience / user friendly)
2. Secondary goals (Efficiency (Using resources in efficient manner) /
Reliability / maintainability)
Major Components of operating system
1. Kernel
- Central Component : Manages the system's resources and communication between hardware and software.
2. Process Management
- Process Scheduler : Determines the execution of processes.
- Process Control Block (PCB) : Contains process details such as process ID, priority, status, etc.
- Concurrency Control : Manages simultaneous execution.
3. Memory Management
- Physical Memory Management : Manages RAM allocation.
- Virtual Memory Management : Simulates additional memory using disk space.
- Memory Allocation : Assigns memory to different processes.
4. File System Management
- File Handling : Manages the creation, deletion, and access of files and directories.
- File Control Block : Stores file attributes and control information.
- Disk Scheduling : Organizes the order of reading or writing to disk.
5. Device Management
- Device Drivers : Interface between the hardware and the operating system.
- I/O Controllers : Manage data transfer to and from peripheral devices.
6. Security and Access Control
- Authentication : Verifies user credentials.
- Authorization : Controls access permissions to files and directories.
- Encryption : Ensures data confidentiality and integrity.
7. User Interface
- Command Line Interface (CLI) : Text-based user interaction.
- Graphical User Interface (GUI): Visual, user-friendly interaction with the OS.
8. Networking
- Network Protocols : Rules for communication between devices on a network.
- Network Interface : Manages connection between the computer and the network.
Batch Operating System
4. To speed up the processing job with similar types (for e.g. FORTRAN jobs, COBOL jobs etc. )
were batched together and were run through the processor as a group (batch).
5. In some system grouping is done by the operator while in some systems it is performed by the
'Batch Monitor' resided in the low end of main memory)
6. Then jobs (as a deck of punched cards) are bundled into batches with similar requirement.
Spooling
Simultaneous peripheral operations online
1. In a computer system input-output devices, such as printers are very slow relative to the
performance of the rest of the system.
2. Spooling is a process in which data is temporarily held in memory or other volatile storage to
be used by a device or a program.
4. Ever had your mouse or keyboard freeze briefly? We often click around to test if
it's working. When it unfreezes, all those stored clicks execute rapidly due to the
device's spool.
Multiprogramming Operating System
- Multiple Jobs : Keeps several jobs in main
memory simultaneously, allowing more
efficient utilization of the CPU.
- Job Execution : The OS picks and begins to
execute one of the jobs in memory.
- Waiting Jobs : Eventually, a job may need
to wait for a task, such as an I/O operation,
to complete.
Processor वकसी के विए wait नहीीं करेगा
- Advantages:
- High CPU Utilization: Enhances processing efficiency.
- Less Waiting Time: Minimizes idle time.
- Multi-Task Handling: Manages concurrent tasks effectively.
- Shared CPU Time: Increases system efficiency.
- Disadvantages:
- Complex Scheduling: Difficult to program.
- Complex Memory Management: Intricate handling of memory is required.
Multitasking Operating system/time sharing/Multiprogramming with Round Robin/ Fair Share
- Time sharing (or multitasking) is a logical extension of multiprogramming, it allows many users to share the computer simultaneously. the CPU executes multiple jobs (May belong to different user) by switching among them, but the switches occur so frequently that, each user is given the impression that the entire computer system is dedicated to his/her use, even though it is being shared among many users.
- In the modern operating systems, we are able to play MP3 music, edit documents in Microsoft Word, surf the Google Chrome all running at the same time. (by context switching, the illusion of parallelism is achieved)
- For multitasking to take place, firstly there should be multiprogramming i.e. presence of multiple programs ready for execution. And secondly the concept of time sharing.
