Operating Systems PDF

OPERATING SYSTEM Link: https://www.youtube.com/watch?v=p3q5zWCw8J4 What is an Operating System and what are its main functions? Benefits of Operating Systems Drawbacks of Operating Systems The operating system is a very important systems software. It is a program that manages all the resource...

OPERATING SYSTEM Link: https://www.youtube.com/watch?v=p3q5zWCw8J4 What is an Operating System and what are its main functions? Benefits of Operating Systems Drawbacks of Operating Systems The operating system is a very important systems software. It is a program that manages all the resources of the computer system. It is a software component of the computer system that is responsible for the management and coordination of activities and the sharing of the resources of the computer. It is a program that acts as an intermediary between the user of the computer and the computer hardware. An operating system (OS) is a component of system software that controls computer hardware and software whilst also offering common functions to programs Despite the fact that application code is normally executed directly by the hardware and frequently communicates with an OS function or is disrupted by it, the OS serves as a bridge between programs and computer hardware for hardware functions such as input and output and memory utilization. The main purpose of the operating system (OS) is to provide an environment within the hardware so that users can execute their programs smoothly without mishaps or glitches. It also serves as a platform where other programs can run. The environment created by the operating system should provide efficiency of the hardware component and convenience of the user. for the user for the system the user-friendly operating system provides ease The operating system sustains the efficiency and accessibility. in the management and use of the computer system and its resources. It acts a host and provides a stable and consistent way for applications to deal with the hardware, and It also ensures that the different applications hide the complexities without having to know all the running at the same time do not interfere with details of the hardware (abstraction). each other. As an important figure, the operating system acts as a receptionist, a dispatcher, a security guard, a manager,a traffic officer,and an accountant (Schneider &Gersting, 2016) as a receptionist as a dispatcher It handles the user interface. it provides services for managing the queue of As the computer is booted, the first point of programs scheduled for processing and activation. contact will be the operating system. It is considered the welcoming committee which assists the user all throughout his/her contact with the hardware. as a security guard as a traffic enforser It controls the access to the system and files. it directs the passage of data through the CPU and It prohibits unauthorized users access to the guides the CPU when to look in memory, when to system. read or write on the data storage, when to display It also prevents user from accidentally or on screen the data or provide a hard copy using the intentionally interfering with each other. printer. as a manager as a accountant It handles the efficient allocation of resources. A resource is any object that can be allocated it monitors the users who logs-on to the system, within the system. what kinds of resources are utilized by each user, It performs the following tasks: and what resources are requested by each user. Monitors resources continuously In other words, it keeps track of how a file has been Enforces policies and decides which gets what, accessed, who accessed it, what file, and when it how much and when was accessed. Allocates the resources De-allocates the resources Operating Systems (OS) are essential for managing computer hardware and software resources but have drawbacks. Here are a few common ones: Some Operating Systems, like macOS and Windows, can be expensive to purchase and maintain. Programming and managing an OS can be complex, requiring specialised knowledge and skills. If the central OS fails, it can impact the entire system, leading to downtime and potential data loss. Operating Systems can be targets for malware and Cyber-attacks, requiring constant updates and security patches. Not all hardware and software are compatible with every OS, which can limit functionality and require additional resources to manage. Some Operating Systems can be resource-intensive, requiring significant memory and processing power. 1ST GENERATION 1940's Serial Processing began the Evolution of Operating Systems. It marked the start of the development of electronic computing systems as alternatives to mechanical computers. Programmers operated the machine themselves There is no Operating System in this generation, the computer system is given instructions that must be carried out immediately. Limitations Inefficiency Time-consuming 2ND GENERATION 1950's - 1960's Batch Operating System A type of system developed for the earliest computers that used punched cards or paper tapes as input and is entered in “batches”. Efficiency of the system was measured in throughput and turn-around. Advantages: Disdvantages: Resource Optimization Lack of Interactivity Workload Management Limited Adaptability Automation Reduced Responsiveness 2ND GENERATION 1955 - 1965 Batch Operating System System/360 Operating System DEC's TOPS-10 JOB SUBMISSION jOB sCHEDULING Developed by Digital Equipment OUTPUT jOB EXECUTION Corporation (DEC) for the PDP-10 mainframe computer in the late 1960s, Introduced in the 1960s, IBM's TOPS-10 was another influential batch System/360 was one of the earliest and processing system. most influential batch operating systems. 2ND GENERATION 1955 - 1965 Batch Operating System Payroll Processing Billing and Invoicing Banking Transactions 2ND GENERATION 1955 - 1965 Single User Operating System An operating system controlled by one user at a time who dealt with one set of input devices. Advantages: Disadvantages: Personalization Limited Collaboration Ease of Use Resource Underutilization Resource Allocation Scalability Challenge 2ND GENERATION 1955 - 1965 single user operating system Palm OS MS-DOS (Microsoft Disk Operating System) MS-DOS was one of the most popular Palm OS was designed for ease of use single-user operating systems in the with a touchscreen-based graphical 1980s and early 1990s. It was user interface. It was provided with a command-line based and used in IBM suite of basic applications for personal PCs and compatibles. information management. 2ND GENERATION 1955 - 1965 single user operating system gaming consoles HOME PCs 3RD GENERATION 1965 - 1985 Multiuser Operating System ·Allowed a single computer – often mainframe– to deal with simultaneous input, output, and processing request from many users. Permits several users to access a single system running to a single operating system. Advantages: Disdvantages: Resource Sharing Complexity Cost Efficiency Security Risks Centralized Management Performance Variation 3RD GENERATION 1965 - 1985 Multiuser Operating System UNix operating Linux operating window server system system 3RD GENERATION 1965 - 1985 Multiuser Operating System Enterprise Educational Networks Institutions 3RD GENERATION 1965 - 1985 Multi- programming Operating Systems The operating system that allows multiple software processes to run simultaneously. Also called multi-tasking operating system which can either be cooperative multitasking or preemptive multitasking. Advantages: Disdvantages: Enhanced Throughput Contention for Resources Resource Optimization Complex Resource Management Time Sharing Potential Deadlocks 3RD GENERATION 1965 - 1985 Multi- programming Operating Systems Database Management Web Servers Video Editing 3RD GENERATION 1965 - 1985 Time Sharing Operating System A system that allows each user to interact directly with the operating system via commands entered from a keyboard. Provides immediate feedback to the user and response time can be measured in minutes or seconds Advantages: Disdvantages: Interactive Computing System Overload Resource Utilization Fairness Challenges Cost Efficiency Security Concerns 3RD GENERATION 1965 - 1985 Time Sharing Operating System Cloud Web Hosting Academic Computing Services Environments 4TH GENERATION 1985 Real Time Operating System (RTOS) This specialized system operates with split-second precision, catering to time-sensitive tasks that require impeccable timing, such as industrial automation or medical equipment control. Advantages: Disdvantages: Precision Timing Complexity Critical Applications Resource Allocation Deterministic Behavior Limited Flexibility 4TH GENERATION 1985 Real Time Operating System (RTOS) Industrial Medical Aerospace and Automation Equipment Defense 4TH GENERATION 1985 Network Operating System (NOS) It facilitates the sharing of resources and collaboration among devices, yet the intricate dance of network connectivity can introduce occasional communication hiccups. Also known as Server Operating Systems, Distributed Operating System or Loosely Coupled System Advantages: Disdvantages: Resource Sharing Network Dependency Fault Tolerance Complexity Collaborative Computing Security Concerns 4TH GENERATION 1985 Network Operating System (NOS) Content Distributed Grid Computing Delivery Databases Networks (CDNs) 5TH GENERATION Multi-Processing System An OS that will manage systems containing hundreds or even thousands of processors The Multi-Processing System emerges as a powerhouse when the demand for computational prowess peaks. Advantages: Disdvantages: Enhanced Performance Synchronization Complexity Resource Utilization Programming Challenges Parallelism Scalability 5TH GENERATION Multi-Processing System Financial Scientific Video Rendering Modeling Simulations MICROSOFT OFFICE Linux ·Windows collectively describes any or all of several ·A Unix-like operating systems built around the Linux Kernel generations of Microsoft (MS) operating system (OS) products written by Linus Torvalds. developed by Microsoft Corporation usually categorized as 16 ·Developed as an open sourceand free software. bit OS environment, hybrid 16/32 bit OS, 32 bit OS environment, and 64 bit OS. Solaris MacOs ·A Unix-Based operating system introduced by Sun ·Graphical user interface based operating systems developed Microsystems by Apple Inc. for their Macintosh line of computer systems. ·Developed originally as a proprietary software but now ·Compatible with both PowerPC and Intel Processors. considered a mixed closed source / open source. Its open sourced software is OpenSolaris  It controls when processes start, stop, and work together. The OS manages allocating and deallocating memory space to processes. processor management memory management functions of I/o operating systems Allocates the I/o channels to communicate with specific device manager Operating systems ensure that all accepting commands to and/or access to system resources is receive data from devices which in security secure. turn interfaces with the OS and software application file management The OS handles data storage, retrieval, and organization on storage devices.  Given that the operating system is responsible for processor management, memory management, security, file management, and I/O management, how might a failure in one of these components affect the overall functionality and security of a computer system? Central processing unit Where program are run or executed. kernel’s job Takes responsibility for deciding at any time which of the running programs may be allocated the processor. Memory Where program instructions and data are stored. Both should be inside the memory in order to be processed by the CPU. Programs usually require more memory than what is available. kernel’s job Chooses on which part of the memory each process can be used, and decides on what to do when there is no enough memory available. devices Devices used to be able to interact with the application program kernel’s job Grants request of users to perform I/O using the appropriate device and offer convenient methods for using these I/O devices. Files Data stored on disks or other storage devices using files. These files are structured in a specific ways to allow faster access. kernel’s job Kernel should be able to access specificfile systems by translating commandssubmitted by user. Keeps track of storage resources.  H O The operating system must ensure the A T PR RD E C correct operation of the computer W TI system. A ON RE N C RY O TE O TI O M P R ME The appropriate mechanism that makes a OPERATING functional operating system which will ensure smooth operation should include SYSTEM N Hardware Protection O TI TE O I/O Protection O I/ C CPU Protection PR Memory Protection PR C C O P U TI TE O N HARDWARE PROTECTION Dual Mode of Operation: User Mode: H O A T When a computer application is running PR RD E C W TI Some examples are word application, PowerPoint, reading a PDF file A ON RE N C RY O and browsing the internet. TE O TI O M P R ME OPERATING Monitor Mode SYSTEM When an interrupt occurs, the operating system gains control of the N O computer. TI TE O O I/ C PR PR C EC O P U TI T O N  H O A T PR I/O PROTECTION RD E C W TI A ON RE N C RY O To protect user program from disturbing normal operation like issuing TE O TI O M P R ME illegal I/O instructions, the operating system must define all I/O OPERATING instructions to be privileged instructions. SYSTEM N O TI TE O O I/ C PR PR C EC O P U TI T O N  MEMORY PROTECTION To protect user programs from one another and also protect it from the operating system, one possible way H O A T PR is to separate each program’s memory space by RD E C W TI providing a range of legal addresses it can access. A ON RE N C RY O TE O TI O M P R ME OPERATING SYSTEM N O TI TE O O I/ C PR PR C C O P U TI TE O N  H O A T PR RD E C W TI A ON RE N C RY O CPU PROTECTION TE O TI O M P R ME To prevent a user program from getting stuck in an OPERATING infinite loop, and never returning control to the SYSTEM N operating system, a timer should be set to interrupt the O TI TE O O I/ C hardware at specific time interval. PR PR C C O P U TI TE O N A process is an instance of a program in execution. It needs certain resources such as CPU time, memory, files and I/O devices. It also needs to request for all the resources needed. As the request is granted by the operating system, these resources are used and then released when the process ends. A program may contain many processes which may be sequentially executed. The program by itself is not considered a process becauseit is a passive entityfound in a file on a disk  Process State Description The process is being created. It has New not yet started execution. The process is loaded into memory Ready and waiting to be assigned to a CPU for execution. The process is currently being Running executed on the CPU. The process is waiting for an external event, such as I/O Waiting (Blocked) completion or a resource becoming available. The process has completed Terminated (Exit) execution or was terminated. Resources are cleaned up. AlmaBetter. (n.d.). Types of operating system. AlmaBetter. https://www.almabetter.com/bytes/articles/types-of-operating- system#%223.%20Multi-Processing%20System%22 Great Learning. (n.d.). What is an operating system? Great Learning. https://www.mygreatlearning.com/blog/what-is- operating-system/ Albano, G. M. (n.d.). Advanced Operating Systems (2021st ed.). O. Padallan, Jocelyn (2023). Introductory guide to operating systems. Arcler Press