Lecture 3 - Operating System PDF

IT Maintenance & Support Lecture 3 By Nawroz F.lawa 2024-2025 Operating System  Outlines  Introduction  Operating System  History of Operating System  Functions of Operating System  Types of Operating System  Some P...

IT Maintenance & Support Lecture 3 By Nawroz F.lawa 2024-2025 Operating System  Outlines  Introduction  Operating System  History of Operating System  Functions of Operating System  Types of Operating System  Some Popular Operating Systems 3  Introduction Operating System  An Operating System (OS) is a software that acts as an interface between computer hardware components and the user.  Every computer system must have at least one operating system to run other programs.  Applications like Browsers, MS Office, Notepad, Games, etc., need some environment to run and perform its tasks.  The OS helps you to communicate with the computer without knowing how to speak the computer's language.  It is not possible for the user to use any computer or mobile device without having an operating system. 4  Operating System  An operating system (OS) is the program that, after being initially loaded into the computer by a boot program, , manages all of the other application programs in a computer.  The application programs make use of the operating system by making requests for services through a defined application program interface (API).  Users can interact directly with the operating system through a user interface.  These requests/commands further executed through hardwares with the help of kernel. 5  History of Operating System  The first computer, Z1, was made in 1936 – 1938. Unfortunately, this computer ran without an operating system.  Twenty years later, the first-ever operating system was made in 1956 i.e Batch OS.  In the 1960s, bell labs started working on building UNIX, the first multitasking operating system.  In 1977 the apple series came into existence. Apple Dos 3.3 was the first disk operating system.  In 1981, Microsoft built the first operating system called DOS by purchasing 86 – DOS software from a Seattle company.  The most famous Microsoft windows came into existence in 1985 when MS- DOS was paired with GUI, a graphics environment. 6 Functions of Operating System 7  Functions of Operating System  Resource Management: When parallel accessing happens in the OS means when multiple users are accessing the system the OS works as Resource Manager, Its responsibility is to provide hardware to the user. It decreases the load in the system. 8  Functions of Operating System  Process Management: It includes various tasks like scheduling and termination of the process. It also provides mechanisms for synchronization and communication among processes. It is done with the help of CPU Scheduling algorithms. 9  Functions of Operating System  Storage Management: The file system mechanism used for the management of the storage. All the data stored in various tracks of Hard disks that are all managed by the storage manager. Systems have several levels of storage which includes primary storage, secondary storage, and cache storage. Instructions and data must be stored in primary storage or cache so that a running program can reference it. 10  Functions of Operating System  Memory Management: Refers to the management of primary memory. The operating system has to keep track of how much memory has been used and by whom. It has to decide which process needs memory space and how much. OS also has to allocate and deallocate the memory space. 11  Functions of Operating System  File System Management :  Organize and manage files stored in computer  Format and copy disks  List files for users to view  Check available and used space on disk  Copy, rename, delete, move and order  Find lost files, restore corrupted files and backup 12  Functions of Operating System  Security/Privacy Management  Privacy is also provided by the Operating system by means of passwords so that unauthorized applications can’t access programs or data.  Register all programs  Authenticate all users  Maintain basic security  Maintain and recover functional errors  Error messages  Provide fundamental information of processes 13  Functions of Operating System  Device driver  Protocol between operating system and hardware  Aid operating system core to control hardware, provide hardware status, and complete the actual I/O operations  Every device should bear with a specific device driver  After adding hardware or re-installing operating system, all device drivers should be re-installed  Without appropriate driver, the hardware could not operate  Modern operating systems already bundled a device driver database  After hardware installation (maybe after reboot), OS will install the driver automatically  If appropriate driver is found, it will be installed  If not found, require manually install the proper driver  To fully utilize function and characteristics of hardware, you should use drivers originated from manufacturer 14 Functions of Operating System 15  Functions of Operating System  User Interface  The user interface accepts commands to execute programs and use resources and services provided by the operating system. It is of Two types:  CLI (Command Line Interface):Unix, Linux  GUI (Graphical User Interface): Windows, Macintosh (MacOS) 16 Types of Operating System 17  Types of Operating System Batch Operating System:  In Batch OS similar types of jobs were batched together and executed in time. People were used to having a single computer which was called a mainframe.  Access is given to more than one person; they submit their respective jobs to the system for the execution.  The system put all of the jobs in a queue on the basis of first come first serve and then executes the jobs one by one. The users collect their respective output when all the jobs get executed.  It contained a small set of programs called the resident monitor that always resided in one part of the main memory. The remaining part is used for servicing jobs.  Advantage: it eliminates CPU time between two jobs.  Disadvantage: Suffer from Starvation 18  Types of Operating System Multi Programming Operating System  Multiprogramming refers to a technique used in operating systems to maximize the use of computer resources.  The idea behind multiprogramming is to allow multiple basic programs to run on a single processor simultaneously partitioning by the processor’s time and memory resources between them.  In a multiprogramming system, the operating system loads several programs into memory simultaneously and then switches between them in a way that gives the illusion of simultaneous execution.  Multiprogramming is the ability for more than one user to use the computer at a time using a single CPU. 19  Types of Operating System Multi Tasking Operating System  Multitasking means concurrent execution of multiple processes by one user on the same computer utilizing multiple CPUs.  Multitasking operating system uses time-sharing to switch between tasks or processes in a way that gives the illusion of parallel execution.  Unlike multiprogramming, where multiple programs are loaded into memory simultaneously, in Multitasking, a single program is loaded into memory and divided into multiple tasks or threads that can be executed concurrently. 20  Types of Operating System Network Operating System  Network Operating System includes software and associated protocols to communicate with other computers via a network  allow sharing of various files, applications, printers, security, and other networking functions over a small network of computers like LAN or any other private network.  In the network OS, all the users are aware of the configurations of every other user within the network Advantages: 1. New technologies and hardware can easily upgrade the systems. 2. Security of the system is managed over servers. 3. The centralized servers are stable. Disadvantages: 1. Server costs are high. 2. Regular updates and maintenance are required. 21  Types of Operating System Distributed Operating System  A distributed operating system (DOS) is an essential type of operating system. Distributed systems use many central processors to serve multiple real-time applications and users. As a result, data processing jobs are distributed between the processors.  It connects multiple computers via a single communication channel. Furthermore, each of these systems has its own processor and memory. Additionally, these CPUs communicate via high-speed buses or telephone 22  Popular Operating Systems  Microsoft Windows  Mac OS(Macintosh)  Android OS  iOS  Linux  Ubuntu  Chrome OS 23 Thank s! You can find me at [email protected] https://sites.google.com/kti.edu.iq/nawroz-fadhil/ about 2 4