4 Operating System.pdf

Review Computer is made of hardware and software....

Review Computer is made of hardware and software. Hardware are physical components: – System unit, input and output devices and storage devices. This topic is introduction to software Software System Software Software also called a program, is a series of related instructions, System software consist of the program that controls or maintain the organized for a common purpose, that tells the computer what task(s) to operations of the computer and its devices. perform and how to perform them. Serves as interface between user, the application software and the Categories: computer’s hardware. – System software Types of System software: – Application software – Operating system – Utility programs. Operating System Utility program Operating system is a set of programs that coordinates all the activities Type of program that allows user to perform maintenance type tasks among computer or mobile device hardware. usually related to managing a computer, its devices or its programs. OS manages computer hardware resources and provides common It consist of tools and applications that do specific task to improve services for computer program. performance, security and functionality of a computer. It provides a means for users to communicate with the computer and other software. Microsoft Windows, Mac OS and Linux. Operating system functions Operating system functions (Cont.) Most Operating System provides similar functions. establishing internet connection – Starting and Shutting down a computer. monitoring performance – User interface providing file management and other utilities – managing programs updating software automatically – managing memory controlling a network – coordinating tasks administering security – configuring devices – monitoring performance Starting a computer Start Up process A computer or mobile device is turned on by pressing the power button. 1) power supply or battery sends electrical current to circuitry in computer Also known as boot. or mobile device. 2) the electric charge resets processor chip and finds firmware that If the devices is ON, for some reason we need to restart (reboot) contains start-up instructions. 3) check various components to see if they are working properly. 4) loads the operating system kernel and frequently used instructions into memory from a storage media. 5) the operating system in memory takes control of the computer or mobile devices and load system configuration information. Display user interface on the screen and runs any start-up applications. Kernel Shutting Down Kernel is the core of an operating system. User shut down to reduce energy cost, security reason or to clear It manages memory and devices, maintains internal clock, runs program memory. and assign resources such as devices, programs, apps data and Option are shutting down, sleep mode or hibernate mode. information. Both resume to where work was left. Kernel is memory resident, it remains in memory while the computer or Hibernate uses less power than sleep mode used if system will not be mobile device is running. used for extended period of time. Other part of OS is nonresident, they remain in storage until they are needed. User interface Memory management OS provides User Interface (UI) for user to interact with operating To optimize the used of a computer or device’s internal memory. system. This involve the managing of primary memory. User interface control how user enter data and display information on Keeps track of which process is using the main memory screen, It also keep track of available memory Two types of UI: – Graphical User Interface It decides which process get main memory and how much to allocate. – Command-line interface Deallocate process that are finished or terminated. Managing programs Configure Devices Operating system can single tasking or multitasking. A device driver is a program that assist OS to communicate with specific single tasking runs one program at a time device. multitasking runs more than one program concurrently. Each device require its own specific driver. – Foreground program is active programs Device driver loaded when computer starts. – Background running but not in use Monitoring Performance Establish Internet Connection Performance monitor is a program that assess and reports information OS provide tools to establish internet connection, about various computer resources and devices. For wired and wireless connections. Processor, drives , network and memory usage. Connection configuration can be automatic or manual. Helps user to identify problem with resources. Updating Operating system May include automatic update feature. Update provides new feature or correction to program. For operating system, enhancing security, modify driver, fixing errors, improve functionality or expanding features. Free packs are free updates, for registered or activated software Types of operating system Types of operating system Many of the first OS were device dependent and proprietary. Backward compatible- new version of operating system usually Device dependent program is one that runs only on a specific type of recognize and work with application written on earlier version of the computer or mobile devices. Operating system. Proprietary software is privately owned and linted to specific vendor or A new application may not be backward compatible. computer or device model. An application may not upward compatible either. Device-independent program runs on computers and mobile device The three basic categories of OS are provided by a variety of manufacturer. – desktop, server and mobile Desktop Operating System Server OS Desktop operating system also called stand-alone operating system. Server operating system is a multi-user operating system that organizes It works on desktop, laptops and some tablets. and coordinates how multiple users access and share resources on a network. Desktop operating system is also called client operating system because they work in conjunction with server operating system. Designed specifically to support all sizes of network. Client operating system can operate with or without a network. Can handle high numbers of transactions, and support large scale messaging and communications Example, Windows, macOS, UNIX, Linux and Chrome OS Server OS have enhanced security and backup capabilities. Server OS Mobile Operating System May support virtualization, sharing or pooling computing resources, Mobile operating system is designed for mobile devices and consumer such as servers or storage devices. electronics, resides in ROM. A server OS can separate a physical server into several virtual servers. Mobile OS include: Each virtual server then can perform independent, separate functions – calendar and contact management, text messing, email, touch screen, accelerometer, digital camera, media player, speech Example: Window Server, macOS server, UNIX and LINUX recognition, GPS navigation, a variety of third-party apps, a browser and wireless connectivity. Example: Android, iOS and Windows (mobile edition). Utility program Utility program (or utility) is a type of system software that allows a user to perform maintenance type tasks, like managing computer, devices and programs. Most Operating System comes with the utility program. Utility Program File manager Search Tool A tool that performs functions to file management. Tool to locate a file, contact, calendar event, app or other items stored Folder is a named location on storage that contains files. on computer or mobile device Functions are: Items a searched based on certain criteria – Display files on storage medium It can look through documents, photos, music, calendars, contacts or – Organize files in folders internet. – Copy, rename, delete, move or sort files Uses an index to locate items quickly. Uninstaller Disk cleanup A tool that removes a program and any associate entries in the system Tool to search unnecessary files and remove them from computer and files. mobile device. When a program is installed, OS records the information it uses to run Files such as: downloaded program files, temporary internet files, the software in the file system. deleted files and unused program files. Uninstaller deletes files and folder, as well as program entries from In mobile device, it can be duplicate files or photos or large unneeded system file. files Disk Defragmenter Screen Saver Tool that reorganizes files and unused spaces on hard disk.. Causes a display’s screen to show moving image or blank screen if no To access data quicker and program runs faster. keyboard or mouse activity occurs for specified time. OS stores data in first available space in hard disk space in continuous It was used to prevent damage to monitor. order. Now, it is used to prevent viewing of desktop content. Content of file may be scattered (fragmented), making file access is Screen saver is exited by press key on keyboard, or by moving or slow. clinking mouse. Defragmenter tries to rearrange data in continuous order. File Compression Tool PC Maintenance A tool to shrink the size of files that uses less storage space. Identifies and fixes operating system problem Groups multiple files or folder into one compresses file. Detects and repair drive problems and include capability to improve Compressed file is called zipped file performance Uncompress or unzip to restore files and folder to original form Contiguously monitor computer while in use to identify and repair problem before they occur. Backup and restore Power management A tool that allow copy or backup selected files of entire storage medium To monitor laptop or mobile device battery usage. content to another storage location. Shows apps power consumption. Most tools compress files to save storage space. Estimates remaining usage time. Restore tool uncompress the files into original form. Enable power saving mode Summary Common OS features: start and shut down computer, user interface, manage programs, memory, coordinate task, configure device, monitoring performance, update OS, file and disk management tools, Types of OS: desktop, server and mobile. Utility tools includes file, disk and system management tools.