Module 1 Lesson 4 - Components of Operating System PDF

PUP Sto. Tomas Campus Module in OPERATING SYSTEMS Prepared & Compiled by: DR. MELANI L. CASTILLO IT FACULTY Let us Pray!  Module 1 OPERATING SYSTEM CONCEPTS Module Overview This module provides an un...

PUP Sto. Tomas Campus Module in OPERATING SYSTEMS Prepared & Compiled by: DR. MELANI L. CASTILLO IT FACULTY Let us Pray!  Module 1 OPERATING SYSTEM CONCEPTS Module Overview This module provides an understanding of operating systems as an intermediary between the user of a computer and the computer hardware. The purpose of an operating system is to provide an environment in which a user can execute programs in a convenient and efficient manner. An aspect of operating systems is how they vary in accomplishing these tasks. We have mainframe operating systems that optimize utilization of the hardware. While operating system in personal computers support complex games, business application, etc. There are other functions also that the operating system does such as traffic manager, dispatcher, etc. Objectives At the end of this module, the student can be able to: Summarize the objectives and functions of modern operating systems. Determine the functions of a contemporary operating system with respect to convenience, efficiency, and ability to evolve. Compare and contrast different types of operating system. Module 1 – OPERATING SYSTEM CONCEPTS Module 1- Lesson 4: Components of Operating System  Lesson Objectives: To review the basic computer system structure. To know the different components of Operating System. To understand the Operating System Mode.  Computer System Structure Overview Computer system can be divided into four components: Hardware – provides basic computing resources CPU, memory, I/O devices Operating system Controls and coordinates use of hardware among various applications and users Application programs – define the ways in which the system resources are used to solve the computing problems of the users Word processors, compilers, web browsers, database systems, video games Users - People, machines, other computers  Computer Architecture Special busses (roads) connecting all input/output devices to motherboard.  CPU – Central Processing Unit This is the brain of your computer. It performs all of the calculations. In order to do its job, the CPU needs commands to perform, and data to work with. The instructions and data travel to and from the CPU on the system bus. The operating system provides rules for how that information gets back and forth, and how it will be used by the CPU.  RAM – Random Access Memory This is like a desk, or a workspace, where your computer temporarily stores all of the information (data) and instructions (software or program code) that it is currently using. Each RAM chip contains millions of address spaces. Each address space is the same size, and has its own unique identifying number (address). The operating system provides the rules for using these memory spaces, and controls storage and retrieval of information from RAM. Device drivers for RAM chips are included with the operating system.  Component of Operating System A component is a process, program, utility, or another part of a computer's operating system that helps to manage different areas of the computer. A system component is similar to a computer program, but is not something an end-user directly interact with when using a computer.  Components of an Operating System Kernel: Controls most operating system tasks, such as memory and process management. Shell: Manages interaction between installed software and hardware. Process Management: Involves creating, scheduling, and terminating processes. Files Management System: Manages file storage. Command Interpreter: Interprets user commands.  Operating System Mode ❖ The User Mode is concerned with the actual interface between the user and the system. ❖ It controls things like running applications and accessing files. ❖ The Kernel Mode is concerned with everything running in the background. ❖ It controls things like accessing system resources, controlling hardware functions and processing program instructions. ❖ System calls are used to change mode from User to Kernel.  Kernel Kernel is a software code that reside in central core of OS. It has complete control over system. When operation system boots, kernel is first part of OS to load in main memory. Kernel remains in main memory for entire duration of computer session. The kernel code is usually loaded in to protected area of memory. User performs it’s task in user area of memory. This memory separation is made in order to prevent user data and kernel data from interfering with each other. Kernel does not interact directly with user, but it interacts using SHELL and other programs and hardware.  Kernel cont… Kernel includes:- 1. Scheduler: It allocates the Kernel’s processing time to various processes. 2. Supervisor: It grants permission to use computer system resources to each process. 3. Interrupt handler : It handles all requests from the various hardware devices which compete for kernel services. 4. Memory manager : allocates space in memory for all users of kernel service. kernel provides services for process management, file management, I/O management, memory management. System calls are used to provide these type of services.  Starting an Operating System(Booting) ✓ Power On Switch sends electricity to the ✓ BIOS will then look for a small sector at the very beginning of motherboard on a wire called the Voltage Good line. your primary hard disk called MBR ( Master Boot Record). ✓ If the power supply is good, then the BIOS (Basic ✓ The MBR contains a list, or map, of all of the partitions on your Input/Output System) chip takes over. computer‘s hard disk (or disks). ✓ In Real Mode, CPU is only capable of using ✓ After the MBR is found the Bootstrap Loader follows basic approximately 1 MB of memory built into the instructions for starting up the rest of the computer, including the motherboard. operating system. ✓ The BIOS will do a Power-On Self Test (POST) to ✓ In Early Kernel Initialization stage, a smaller core of the Kernel is make sure that all hardware are working. activated. ✓ This core includes the device drivers needed to use computer‘s RAM chips.  BIOS BIOS (basic input/output system) firmware was stored in a ROM/EPROM (Erasable Programmable Read-Only Memory) chip known as firmware on the PC motherboard. BIOS can be accessed during the initial phases of the boot procedure by pressing del, F2 or F10. Finally, the firmware code cycles through all storage devices and looks for a boot-loader. (usually located in first sector of a disk which is 512 bytes) If the boot-loader is found, then the firmware hands over control of the computer to it.  UEFI UEFI stands for Unified Extensible Firmware Interface. It does the same job as a BIOS, but with one basic difference: it stores all data about initialization and startup in an.efi file, instead of storing it on the firmware. This.efi file is stored on a special partition called EFI System Partition (ESP) on the hard disk. This ESP partition also contains the bootloader. UEFI was designed to overcome many limitations of the old BIOS, including: UEFI supports drive sizes upto 9 zettabytes, whereas BIOS only supports 2.2 terabytes. UEFI provides faster boot time. UEFI has discrete driver support, while BIOS has drive support stored in its ROM, so updating BIOS firmware is a bit difficult. UEFI offers security like "Secure Boot", which prevents the computer from booting from unauthorized/unsigned applications. This helps in preventing rootkits. UEFI runs in 32bit or 64bit mode, whereas BIOS runs in 16bit mode. So UEFI is able to provide a GUI (navigation with mouse) as opposed to BIOS which allows navigation only using the keyboard.  Shell Shell is a computer application software that the services of an operating system to an external user or another program. Depending on the computer's particular operation and role, its shell may have either a command line interface (C.L.I.) or a graphical user interface (G.U.I.). As suggested by the name, the shell is the outermost layer in an operating system. Shells in most operating systems are not direct interfaces to the kernel that lies beneath, even if the shell communicates with the program or user through peripheral devices directly attached to the computer system.  Command Interpreter Command interpreter provides a command-line interface. It allows the user to enter a command on the command line prompt (cmd). The command interpreter accepts and executes the commands entered by a user. For example, a shell is a command interpreter under UNIX. The commands to be executed are implemented in two ways: The command interpreter itself contains code to be executed. The command is implemented through a system file. The necessary system file is loaded into memory and executed.  End of Lesson 2 Any Questions  References: 1. Silberschatz, A., Galvin, P., and Gagne, G.(2018). “Operating ‘System Concepts”, 10th ed. John Wiley and “Sons Inc. 2. Stalling, William.(2018), “Operating Systems: Internals and Design Principles”, 9th ed. Pearson Education Enc 3. Lecture-Note -Vinod Sencha, Core Faculty(IS), RTI Jaipur  Lesson Assessment Answer the following review questions: 1.What are the major components of Operating System that are responsible for the computer system to boot? 2.What is kernel and its functions?  Lesson Assignment: Assignment#1 1. Do advance Research study3ofOperating at least Module 1 –system Lesson 3 2. Be ready for a recitation next meeting. Compare them based on the following: Features Reading & Functions Assignment : Advantages and Disadvantages http://openbookproject.net/courses/intro2ict/system/os_intro.html#:~:text=An%20operating%2 0system%20(OS)%20is,are%20run%20on%20the%20machine.&text=Almost%20all%20comp uters%20use%20an%20OS%20of%20some%20type. https://www.geeksforgeeks.org/introduction-of-operating-system-set-1/ https://www.studytonight.com/operating-system/introduction-operating-systems https://www.guru99.com/operating-system-tutorial.html https://www.tutorialspoint.com/operating_system/index.htm  References : Nutt, G. (2009), Operating Systems: A Modern Perspective, 3rd Edition, Pearson Addison-Wesley Inc, Boston , Massachusetts. Silberschatz, A., Galvin, P., and Gagne, G.(2018). ―Operating ‗System Concepts‖, 10th ed. John Wiley and ―Sons Inc. Stallings, Wiliam. (2018). ―Operating Systems: Internals and Design Principles‖ 9th ed. Pearson Education Inc. Harris, J. Archer., ―Schaum‘s Outline of Theory and Problems of Operating Systems. McGraw Hill Companies Inc., 2002 https://ssmengg.edu.in/weos/weos/upload/EStudyMaterial/Cse/6th%20sem/Operating%20system/operating%20system.pdf https://techterms.com/definition/operating_system https://www.geeksforgeeks.org/types-computer-memory-ram-rom/ https://www.tutorialspoint.com/operating_system/operating_system_tutorial.pdf https://www.geeksforgeeks.org/types-of-operating-systems/