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What is an Operating System 1.pptx OSY!2

An Operating System (OS) is system software that acts as a bridge between the user and computer hardware. It manages CPU, memory, files, devices, security, and other resources. The PPT covers the five generations of OS, from vacuum tubes to modern AI-based systems. It also explains OS functions and types such as Batch, Multiprogramming, Multitasking, Real-Time, Distributed, and Mobile OS.

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What is an Operating System? - An operating system acts as an intermediary between the user of a computer and computer hardware. In short its an interface between computer hardware and user. - An Operating System is a program that manages overall resources and operations of the computer. - The purpose of an operating system is to provide an environment in which a user can execute programs conveniently and efficiently.
Every general-purpose computer consists of hardware, an operating system(s), system programs and application programs. The hardware consists of memory, CPU, ALU, I/O devices, peripheral devices and storage devices. The system program consists of compilers, loaders, editors, OS, etc. To understand more fully the operating system’s role, we next explore operating systems from two viewpoints: that of the user and that of the system.
User View : • The user's view of the computer varies according to the interface being used • System Design for Single User • Multiple User – Mainframe or Minicomputer • Workstations connected to networks of other workstations and servers System View : • From the computer's point of view, the operating system is the program most intimately involved with the hardware. • we can view an operating system as a resource allocator • A computer system has many resources that may be required to solve a problem: CPU time, memory space, file-storage space, I/0 devices, and so on.
Goals of Operating System : • User Convenience : It should be easy to use, providing a user-friendly interface and making it simple to interact with the system. • Program Execution: It facilitates the execution of user programs, providing the necessary environment and services for them to run. • Resource Management: The OS manages and allocates the computer's resources, including the CPU, memory, disk storage, and input/output devices, to ensure fair utilization. • Security: The OS protects the system and user data from unauthorized access, ensuring the confidentiality, integrity, and availability of information.
First Generation of OS : 1940 to 1955 Technology : Vacuum tubes were the core components for logic and circuitry. Size : Computers were enormous, often filling entire rooms. Power Consumption & Heat : They consumed vast amounts of electricity and produced considerable heat, causing reliability issues. Memory : Magnetic drums were used for storing data and programs. Programming Language : Programming was done in machine language, a low-level binary code. Input/Output : Punched cards and paper tape were the primary input and output methods. Processing : Computers could only solve one problem at a time and required days to set up for a new task.
Examples: ENIAC (Electronic Numerical Integrator and Computer):A large, general-purpose computer known for its 18,000 vacuum tubes. EDVAC (Electronic Discrete Variable Automatic Computer):Designed by John von Neumann, it could store both data and instructions, improving speed. UNIVAC (Universal Automatic Computer):The first commercial computer, delivered to a business client, the U.S. Census Bureau, in 1951.
Advantages : 1.Faster than doing calculations by hand. 2.Helped in scientific and military research. 3.Could process more data than humans. 4.Gave the basic ideas for modern computers. 5.Started the development of computer science. Disadvantages : 1.Very big in size, took up a whole room. 2.Used a lot of electricity and produced heat. 3.Very costly to buy and maintain. 4.Broke down often because of vacuum tubes. 5. Slow compared to later computers.
Second Generation of OS : 1955 to 1965 Transistors over Vacuum Tubes The most significant innovation was the replacement of vacuum tubes with transistors, leading to smaller, less heat-generating, and more durable computers. Improved Speed and Efficiency Calculations became significantly faster, with processing times measured in microseconds, compared to milliseconds in the first generation. Lower Power Consumption Transistors consumed less electricity, making these computers more energy-efficient. Assembly and High-Level Languages Programming languages evolved from machine code to more user-friendly assembly languages and high -level languages like FORTRAN and COBOL. Memory and Storage Primary memory was handled by magnetic cores, while magnetic tapes and disks served as secondary storage devices. Operating Systems Batch processing and multiprogramming operating systems were introduced, increasing efficiency.
Example : GM-NAA I/O was the first operating system made in 1956 by General Motors and North American Aviation for the IBM 704 computer. It used batch processing, which means it could run programs one after another automatically, without needing someone to start each one. This made the computer work faster and saved time. Computer Used : IBM 1401: Widely used for business applications, known for high-speed data processing. IBM 7094: Advanced scientific computer, popular in research and military applications. UNIVAC 1108: High-performance system for scientific and business data processing. CDC 6600: One of the first supercomputers, designed for complex scientific calculations. B5000: Innovative for its time, focused on business data processing with advanced architecture.
Advantages : 1.Smaller in size – used transistors, so not as big as first-generation computers. 2.More reliable – transistors were stronger and failed less often. 3.Used less electricity – produced less heat (but still needed cooling). 4.Faster – could process data much quicker than first-generation. 5.More accurate – gave better results with fewer mistakes. 6.Easier to move – smaller size made them easier to use in different places. Disadvantages : 1.Still needed cooling – though better than before, they could still overheat. 2.Needed maintenance – had to be checked and repaired regularly. 3.Expensive – making them was still very costly. 4.Limited use – mostly used for science and business, not for general purposes. 5.Slow input method – relied on punch cards, which were time-consuming.
Third Generation of OS : 1965 to 1971 -Used Integrated Circuits (ICs) instead of transistors. -An IC is a small chip that contains many transistors, resistors, capacitors, and the necessary connections all in one piece, making computers smaller and more efficient. -This invention, by Jack Kilby, made computers more reliable and faster. -In the previous generation, the computational time was microsecond, which was decreased to the nanosecond. -In this generation, punch cards were replaced by the mouse and keyboard. New systems introduced Remote processing – work done from a distance. Time-sharing – many users could share the computer at the same time. Multiprogramming – computer could run multiple programs together.
Examples : OS/360 : A landmark operating system for the IBM System/360, famous for its complexity and introduction of multiprogramming. Unix : A foundational operating system that emerged from this period, becoming the basis for many modern operating systems. Computers Used : IBM 360 Series,Honeywell-6000 Series,PDP (Personal Data Processor),IBM 370 Languages Used : FORTRAN(Formula Translation) COBOL(Common Business Oriented Language ) PASCAL BASIC(Beginners All-purpose Symbolic Instruction Code) ALGOL(Algorithmic Language) C
Advantages : 1.Smaller in size – ICs made computers compact and space-saving. 2.Used less electricity – more energy-efficient, produced less heat. 3.More reliable – ICs were stronger, with fewer hardware failures. 4.Easier to use – keyboards and mice replaced punch cards. 5.More storage & accurate results – could handle larger data and calculations correctly. 6.Faster & portable – smaller size and higher speed made them easier to move and more efficient. Disadvantages : 1.Still needed air-conditioning – to avoid overheating. 2.ICs were complex to make – manufacturing was difficult and costly. 3.Hard to repair – fixing or replacing ICs was complicated. 4.High setup cost – still expensive compared to modern computers. 5.Software issues – some older programs didn’t work on new systems. 6.Skilled people needed – required trained staff to operate and maintain.
Fourth Generation OS 1971 to 1980 : -Use of Very Large Scale Integrated (VLSI) circuits, which integrated thousands of transistors onto a single chip to create microprocessors. -Microprocessors used – thousands of ICs were combined into a single chip called a microprocessor. -Smaller and cheaper – computers became very compact, affordable, and fit on desks (personal computers). -More powerful – could process data much faster and handle complex tasks easily. -More reliable – fewer chances of failure compared to older generations. -Large storage – hard disks and floppy disks gave more memory for saving data. -Better user interface – used monitors, keyboards, and later graphical interfaces (like Windows). -Networking – computers could connect through LAN and later the internet. -Portable – laptops and smaller devices became possible.
Examples : Operating systems such as CP/M and Apple DOS emerged, making computing accessible to individuals and small businesses. MS-DOS became a dominant operating system for personal computers Unix were used in business and scientific applications Microsoft Windows Computer Used : DEC 10,STAR 1000,PDP 11,CRAY-1(Super Computer),CRAY-X-MP(Super Computer) Languages Used : C,C++,Pascal,COBOL,FORTRAN and SQL,dBASE,FoxPro
Fifth Generation OS 1980 onwards 1.Based on Artificial Intelligence (AI) – designed to think and make decisions like humans. 2.Very fast – use advanced processors and supercomputing power. 3.Natural language processing – can understand human language (speech recognition, translation, chatbots). 4.Machine learning – computers can learn from data and improve themselves. 5.Robotics – used in robots to perform human-like tasks. 6.Advanced connectivity – internet, cloud computing, and IoT (Internet of Things). 7.Portable devices – smartphones, tablets, and modern laptops. 8.User-friendly interfaces – touchscreens, voice assistants (like Siri, Alexa, Google Assistant,Gemini).
Advantages : 1.Very fast and powerful. 2.Can think and learn using AI. 3.Easy to use – supports voice, image, and touch input. 4.Smaller and portable – smartphones, tablets, etc. 5.Can handle large data (Big Data, Cloud) easily. 6.Useful in almost every field – medicine, education, space, business, research. Disadvantages : 1.Very expensive to make and maintain. 2.High power consumption for supercomputers. 3.Unemployment risk – many jobs replaced by AI and automation. 4.Security risks – hacking, cybercrime, and misuse of AI. 5.Over-dependence on technology – people may lose creativity and problem-solving skills. 6.Ethical issues – fear of machines becoming too powerful or misused.
Examples : Android,Microsoft Windows,iOS,macOS,Linux,ChromeOS Languages Used : Python,JavaScript,Java,C++,C#,GO,Rust,Swift,Kotlin,PHP,SQL Computer Used : Personal Computer,Laptops,Tablets,Smartphones
Functions of Operating System :
Functions of Operating System : • Process Management • The OS runs many programs at the same time. • It decides which program will use the CPU and when. • Memory Management • The OS gives memory (RAM) to programs when they need it. • It takes it back when the program is finished. • File Management • The OS stores files on hard disks, pen drives, etc. • It helps us create, open, save, delete, and organize files. • Device Management • The OS controls devices like keyboard, mouse, printer, etc. • It makes sure input and output devices work properly. • Security • The OS protects the computer from unauthorized users. • It uses passwords, permissions, and other safety features.
• User Interface • The OS gives us a way to interact with the computer. • It may be Command Line (typing commands) or Graphical (icons, windows, menus). • Networking • The OS helps computers connect and share data over a network or internet. • Error Handling • The OS finds and fixes errors (like printer not working or file missing). • Resource Management • The OS makes sure CPU, memory, and storage are used efficiently.
Types of Operating System : • Batch Operating System • Time Shared Operating System • Multitasking Operating System • Multiprogramming Operating System • Real Time Embedded System • Distributed Operating System • Mobile Os
Batch Processing Operating System : • Batch processing was very popular and used to complete tasks on mainframe computers. • Users did not interact directly with the computer. • Each user prepared their job using an offline device like punch cards. • Jobs with similar needs were grouped together into batches. • The computer operator collected jobs from programmers, sorted them,and submitted them in batches. • A job is a single unit made up of a data, control instructions, and programs.
Working of Batch Processing Operating System
Advantages : Reduces execution time : • Jobs are grouped and processed together, so overall execution time is shorter compared to running them one by one. Shared among multiple users : • Many users can submit jobs to the system, and the OS handles them fairly by grouping and scheduling them. Error handling is effective : • If one job has an error, it doesn’t stop the execution of other jobs in the batch. Errors are reported after the batch is complete. Jobs can be divided into smaller parts : • Large jobs can be broken down and processed in pieces, which speeds up execution. Automatic job execution : • Once one job is finished, the next job is automatically taken up by the CPU, reducing idle time. Better CPU utilization • Since jobs are queued and executed in sequence, the CPU remains busy and is used more effectively.
Disadvantages : Job failure causes delay : • If a job fails, it has to be rescheduled, which may take a lot of time and slow down other jobs. No direct interaction with users • Once jobs are submitted, users cannot change, update, or interact with them during execution. No job priority • All jobs are executed in the order they arrive (First Come, First Serve). Important or urgent jobs cannot jump ahead. Starvation problem • Some jobs may be delayed for a very long time if batches are very large or other jobs keep arriving. CPU idle time • While jobs are being loaded or unloaded, the CPU may sit idle, which lowers efficiency. No real-time processing • Batch OS cannot handle tasks that require instant results (like medical monitoring or flight control).
Examples : Payroll Processing Systems : • Salaries for thousands of employees are calculated in one batch (all at once) at the end of the month. Banking Systems : • End-of-day processing of transactions (like updating balances, interest calculation, or report generation) is done in batches. Billing Systems : • Utility companies (electricity, water, telephone) generate customer bills in batches at the end of the billing cycle.
Multiprogramming Operating System : • Multiprogramming means running many programs at the same time on one computer. • If one program is waiting for input/output (like keyboard, disk, printer), the CPU works on another program. • This makes sure the CPU is never idle and always busy. • The operating system keeps several programs in memory and switches between them. • Each running program is called a task, process, or job. • It helps to use computer resources better and finish more work in less time. • The main purpose is to manage memory, files, and input/output devices properly.The OS makes sure all programs share resources smoothly.
Advantages : Higher CPU utilization: The CPU is kept busy by switching between multiple jobs, which prevents it from sitting idle. This is the main goal of multiprogramming. Increased throughput: By running multiple jobs concurrently, more work can be completed in a given amount of time. Reduced response time: Shorter jobs get a chance to run and finish quickly, which reduces their wait time. Efficient resource utilization: System resources, like I/O devices, are used more effectively since they can be allocated to different jobs.
Disadvantages : Increased complexity: The operating system is more complex because it must manage multiple jobs, handle memory allocation, and perform CPU scheduling. CPU scheduling: A sophisticated scheduling algorithm is required to decide which job to run next. Memory management: Main memory must be carefully managed to hold multiple programs at once, which can be challenging. Potential for long wait times: If there are many short jobs, a long-running job might have to wait for a long time before it gets its turn to run.
Example : • Examples of multiprogramming operating systems you use today, such as Windows, macOS, and Linux. • These operating systems are built on the principles of multiprogramming to allow you to run multiple applications at once.
Multitasking/Time Sharing Operating System : • A multitasking operating system is one that allows a computer to execute multiple tasks or run multiple programs at the same time. • The OS uses the round robin scheduling method where each task is given a fixed time slice called a time quantum. • After the time quantum ends, the OS switches (context switching) to the next task in the queue. • The OS manages CPU, memory, storage, and input/output devices.It ensures that every process gets the resources it needs without clashing with others. • The CPU executes one task at a time but switches so fast that it appears as if all programs are running simultaneously.
Advantages : • Can execute multiple applications simultaneously without slowing down the system. • Uses time-sharing (each process gets a small time slot), so processes don’t have to wait long for CPU time. • Prevents starvation of processes, as every task gets a fair chance. • Effectively manages I/O devices, RAM, hard disks, CPUs, and other resources. • Allows users to run multiple programs at the same time (e.g., games, browser, MS Word). • Provides well-defined memory management, preventing unwanted apps from wasting RAM.
Disadvantages : • Requires more memory (RAM) and processing power compared to single-tasking systems. • Frequent context switching creates overhead and may slow down system performance. • Running too many tasks at once can make the system lag, crash, or overheat the CPU. • If the processor is not powerful enough, the system may become slow while multitasking. • Overloaded RAM or insufficient memory can cause performance issues.
Example : 1. Windows (e.g., Windows 10, 11) 2. Linux (e.g., Ubuntu, Fedora, Red Hat) 3. macOS (Apple) 4. Android (Mobile OS) 5. iOS (Apple Mobile OS)
Real Time Embedded System : • A Real-Time System is a computer system that must complete specific tasks within a fixed time limit; if tasks are delayed, the system may fail. • An Embedded System is a mix of hardware and software built for a specific task, unlike general-purpose computers. Example: washing machine controller, car engine control. • Some embedded systems work independently, while others work as part of a larger system. They usually require little or no human intervention. • When an embedded system is designed to handle real-time tasks (tasks that must finish within a deadline), it is called a Real-Time Embedded System.
Types of Real-Time Embedded Systems : Hard Real-Time Embedded System : • Must always meet deadlines. • Very strict and accurate in design. • Used in critical applications where delays can cause failure. • Example: Pacemakers, flight control systems, car airbags. Soft Real-Time Embedded System : • Deadlines are important, but small delays are allowed. • Simpler in design, but less accurate than hard systems. • Example: Video streaming, online games, multimedia players.
Advantages : • Fast Response : Does tasks quickly and on time. • Reliable : Works correctly and consistently. • Efficient : Uses less power and hardware. • Automatic : Can control things without humans. • Small & Cheap : Compact design saves space and cost. Disadvantages : • Hard to Design: Needs careful planning to work correctly. • Expensive to Make : Special hardware and testing cost more. • Not Flexible : Made for one task, hard to change. • Hard to Debug : Finding and fixing problems is tricky. • Hardware Dependent : If hardware fails or is slow, system can fail.
Distributed Operation System : • A distributed operating system connects many separate computers so they can work together like one big computer. • Each computer has its own processor (CPU) and memory, but they can talk to each other using networks like LAN, WAN, or other high-speed connections. • Tasks are shared among the computers, so each one does part of the work. This makes processing faster and more efficient. • The computers in the system are called nodes, sites, or processors, and they can be different in size, speed, or purpose. • It allows users to share resources like files, printers, and storage devices across the network easily. • For users, the whole system looks like one single computer, even though the work is happening on many computers at the same time.
Advantages : • Resource Sharing : Computers can share disks, CPUs, printers, and other devices, making resources available to everyone in the network. • Data Safety : Data is copied at multiple locations, so if one computer fails, data is still safe on another. • System Reliability : If one computer crashes, the rest of the system keeps working. • Faster Communication : Data can move quickly between computers in the network. • Accessible Anywhere : Resources can be used from both local and remote computers. • Faster Processing : Tasks are shared among computers, so work gets done more quickly. • Fault Tolerance : Even if one computer fails, the system continues to function.
Disadvantages : Complex Scheduling : Deciding which computer does what job can be difficult and may waste some resources. Security Issues : Protecting all computers and connections is harder. Complicated Databases : Managing data is more complex than in a single computer system. Difficult Software : The system software is complicated and not easy to understand. Communication Delays : As more computers are added, sending data takes longer. High Cost : Distributed systems are expensive to set up and maintain. Monitoring Problems : Keeping track of all computers and resources in large systems is challenging.
Example : • Amoeba OS • Plan 9 from Bell Labs • Mach OS • Windows Server with Distributed File System (DFS) • UNIX Distributed Systems
Mobile Operating System : • A mobile operating system (Mobile OS) is system software for smartphones, tablets, and wearable devices. • Manages the device’s basic functions like processing and memory. • Runs applications on the device. • Controls memory and resources to ensure smooth performance. • Connects the device to networks like Wi-Fi, cellular, and Bluetooth. • Provides an easy-to-use interface for users. • Acts as a bridge between the hardware and apps, making the device functional and user- friendly.
Key Features of Mobile OS : User Interface (UI) : Provides a touch-friendly interface, allowing users to interact using taps, swipes, pinches, and gestures. Multitasking : Lets multiple apps run at the same time and allows users to switch between them smoothly. Connectivity : Supports Wi-Fi, cellular networks, Bluetooth, NFC, and other connections, enabling devices to communicate with networks and other devices. App Management : Offers an app store or marketplace where users can browse, download, install, update, and remove apps. Memory and Resource Management : Efficiently manages CPU, RAM, storage, and battery, ensuring smooth performance without quickly draining power. Security and Permissions : Protects the device from malware and unauthorized access and lets users control app permissions for camera, location, storage, etc.
Advantages : Easy to Use : Mobile systems are simple and designed so that anyone can use them without much difficulty. Lots of Apps : You can install many apps to do different things like shopping, chatting, gaming, or learning. Stay Connected : They support Wi-Fi, Bluetooth, mobile data, and other options to keep you connected anytime, anywhere. Regular Updates : They get frequent updates for new features, better performance, and security fixes.
Disadvantages : Short Battery Life : Mobile devices still struggle with battery draining quickly if used heavily. Security Issues : Phones can be attacked by viruses, malware, or fake websites, which may steal your data. Different Versions Problem : Especially in Android, many devices have different versions, so apps don’t always work the same everywhere. Less Powerful than Computers : Mobiles have less storage, memory, and processing power than desktops, so heavy apps may run slowly.