Operating Systems and Utility Programs By Humphrey Kumwembe

OBJECTIVES After completing this lesson, you should be able to: Describe the two types of system software Describe the functions of an Operating System. Understand the startup process on a personal computer. Describe the term user interface. Summarize the features for stand-alone, server and embedded operating system. Explain the purpose of several utility programs.

SYSTEM SOFTWARE System software consists of the programs that control or maintain the operations of the computer and its devices. Serves as the interface between the user, the application software, and the computer’s hardware. System Software is divided into two types: OPERATING SYSTEM(OS) DRIVERS UTILITY PROGRAMS

OPERATING SYSTEM(OS) Set of programs that coordinates all activities among computer hardware resources. Resides on optical disc or flash memory or Hard disk(Desktop computers) or ROM chip(Mobile and handheld devices). Sometimes called platform. An application software requires a platform to run. Some applications run on multiple platforms and these are Cross-platform programs.

OS FUNCTIONS Starting up and Shutting down a Computer The process of starting or restarting a computer is called Booting. There is: Cold booting: Starting of computer when is powered off completely. Warm booting: Uses the operating system to restart the computer. (Done after installing updates or new software) The kernel and frequently used operating system instructions are loaded each time a computer is booting. Kernel: Core of the OS: Manages memory and devices. Starts programs. Maintains computer’s clock. Assign computer resources(Devices, programs, data etc.)

OS FUNCTIONS Boot process is done in 7 steps: When you turn on the computer, the power supply sends an electrical signal to devices located in the system unit The processor chip resets itself and looks for the ROM chip that contains the BIOS (basic input/output system), which is firmware that holds the startup instructions. The BIOS executes the power-on self test (POST) to make sure hardware is connected properly and operating correctly. The POST results are compared with data in a CMOS chip on the motherboard. The CMOS chip stores information about; Memory amount Disk drive types Keyboard and monitor. Current date and time. If the POST completes successfully, the BIOS searches for specific operating system files called system files.

OS FUNCTIONS Once located, the boot drive (the drive from which your personal computer starts), loads the system files from storage (the hard disk – usually drive C) into memory (RAM) and executes them. Next, the kernel of the operating system loads into memory and takes control of the computer. The operating system loads configuration information. The registry consists of several file that contain the system configuration information that are constantly accessed by the OS i.e. Hardware and software devices installed and individual user preferences.  Shutdown options: Powering off the computer: This is total shutdown where all processes are completely killed. Sleep mode: Keeps session(Programs and documents) in Memory(RAM), turns off all unneeded functions and place computer in low-power state. If power is removed, all unsaved content is lost. Hibernate: Saves any open documents and programs to a hard disk before removing power from the computer

OS FUNCTIONS

OS FUNCTIONS Providing User Interface(UI) Is the space where interaction between humans and machines occurs. Controls how you enter data and instructions and how information displays on the screen. Two types: Graphical User Interface(GUI): A graphical user interface (GUI) allows you to use menus and visual images such as icons, buttons, and other graphical objects to issue commands. Command-line Interface:

Graphical user Interface

Command-Line Interface

OS FUNCTIONS Managing Programs Some operating systems support a single user and only one running program at a time. Others support thousands of users running multiple programs. How programs are managed affects productivity. A single user/single tasking: Operating system allows only one user to run one program at a time i.e. Dos OS A single user/multitasking: Operating system allows a single user to work on two or more applications that reside in memory at the same time. A program may run in foreground(Active) or background(Not in use). A multi-user: Operating system enables two or more users to run a program simultaneously. i.e. Server OS. A multiprocessing: Operating system supports two or more processors running programs at the same time. Multiprocessing involves the coordinated processing of programs by more than one processor. Multiprocessing increases a computer’s processing speed.

OS FUNCTIONS Managing memory The purpose of memory management is to optimize use of random access memory (RAM). OS allocates or assigns items to memory area while they are being processed. Monitors the contents of memory. OS releases the contents from memory when no longer required. If programs a lot of memory space, OS uses virtual memory to solve the problem. With virtual memory (VM), the operating system optimizes memory by allocating a portion of a storage medium, usually the hard disk, to function as additional RAM.

OS FUNCTIONS Coordinating tasks. Scheduling jobs (operations the processor manages) involves determining the order in which jobs are processed. Configuring devices. A device driver is a small program that tells the operating system how to communicate with a device. Most OS and Devices support Plug-and-Play. Plug and Play means the operating system automatically configures new devices as you install them. Monitoring performance. OS monitors the performance of the system. Monitoring performance helps to identify and solve system problems. A performance monitor is a program that assesses and reports information about various system resources and devices

OS FUNCTIONS Provide file management and other utilities OS provide users with capabilities to manage files. Uses File Manager to: format and copy disks; List the files on a storage medium; Check the amount of used and unused space on a storage medium; Organize, copy, delete, move, and sort files; Create shortcuts (icons on the desktop that run a program when clicked). Administering security. Administering security involves establishing user accounts on a network. Each account typically requires a user name and password to log on, or access, the network.

OS TYPES The three basic categories of OS: Stand-Alone OS: A stand-alone operating system is a complete operating system that works on a desktop or notebook or mobile computer. Some stand-alone OS have networking capabilities allowing them to in conjunction with server OS(Client OS). Examples include Windows 8, Windows 7, Vista, Windows XP, Linux, Mac OS X, Unix, DOS(Disk Operating System) Windows 3.1. Server OS: OS designed to support a network. Client computers rely on server resources. Resource may include data, services, memory etc. Examples include Windows server 2008, Linux, Unix, Windows Server 2003. Embedded OS: OS on mobile devices and many consumer electronics. Resides on ROM Chip. Examples include Windows Embedded CE, Google Android, Palm OS, iPhone OS, BlackBerry.

UTILITY PROGRAMS Programs that perform specific tasks related to managing a computer, its devices, or its programs. Include: File Manager: A utility that performs functions related to file management i.e. Listing of files on Storage medium, copying, deleting, moving and sorting files. Search Utility: A program that attempts to locate a file on your computer based on criteria you specify. Criteria may be word or words in a file. Disk Defragmenter: A utility that reorganizes files and unused space on a computer’s hard disk so data can be accessed more quickly and programs can run faster Back up and Restore: A backup utility allows users to copy, or back up, selected files or an entire hard disk to another storage medium i.e. another hard disk, flash disk. Restore utility reverses the process and returns backed up files to their original form. Backup utilities work with and restore utilities Personal firewall: A utility that detects and protects a personal computer from unauthorized intrusions. Personal firewalls constantly monitor all transmissions to and from a computer.

UTILITY PROGRAMS Spyware and Adware removers: Spyware is a program placed on a computer without the user’s knowledge that secretly collects information about the user, often related to Web browsing habits. Adware is a program that displays an online advertisement in a banner or pop-up window on Web pages, e-mail, or other Internet services. Sometimes, spyware is hidden in adware. A spyware and Adware remover is a program that detects ad removes spyware and adware File compression: Shrinks the size of a file.