Chapter 8 Operating Systems and Utility Programs Serena Oldhouser

System Software  System software consists of the programs that control or maintain the operations of the computer and its devices.  Serves as an interface between user, application software, and computer hardware.

Two Types of System Software  Operating Systems  Set of programs containing instructions that coordinate all the activities among computer hardware resources.  Stored on hard drive  Utility Programs  Performs maintenance tasks

Operating System  Different sizes of computer use different operating systems  Operating system is sometimes called the platform

Functions of an Operating System  Starting the Computer  Recovery Disk  User Interface  Managing Programs  Managing Memory  Scheduling Jobs  Configuring Devices  Establishing an Internet Connection  Monitoring Performance  Administering Security

Starting the Computer  Called Booting  Cold boot- Turning on a computer that has been powered off completely  Warm boot- Restarting a computer that already is powered on  Kernel-Core of an operating system  Manages memory  Starts applications  Assigns the computers resources  Memory resident-Remains in memory while computer is running

Recovery Disk  Special disk used to start the computer when the hard disk becomes damaged and can not boot by itself  Also called a boot disk  Contains a few system files that will start the computer

Command-Line Interface  A user types commands or presses special keys on the keyboard to enter data and instructions  Uses sets of commands called the command language.  Used by advanced users  Difficult to use because they require exact spelling, grammar, and punctuation  Gives more control over setting details

Menu-Driven Interface  Provides menus as a means of entering commands  Easier to learn

Graphical User Interface  Interact with menus and visual images such as icons, buttons, and other graphical objects to issue commands  Used by most users today  Many incorporate features similar to those of a Web browser.

User Interface  Controls how you enter data and instructions and how information is displayed on the screen.  Three types of user interfaces  Command-line  Menu-driven  Graphical

Managing Programs  Single user/single tasking operating system  Allows one user to run only one program at a time  Single user/multitasking operating system  Allows one user to run two or more programs at a time  Only one program can be in the foreground at a time, others are in the background

Managing Programs  Multi-user  Enables two or more users to run programs simultaneously  Multiprocessing  Supports two or more processors running programs at the same time  Fault-tolerant computer  Continues to operate when one of its components fails  Duplicate components such as processors, memory, and disk drives.  Used by Airlines, communications networks & ATM’s

Managing Memory  Necessary to optimize the use of RAM  May run out of RAM when using multiple programs  Virtual memory allocates a portion of a storage medium to function as additional RAM  Slower then RAM

Scheduling Jobs  Operating system determines the order in which jobs are processed  Include receiving data from an input device, processing instruction, sending information to an output device, & transferring items from storage to memory and from memory to storage

Configuring Devices  Driver  Small program that tells the operating system how to communicate with a specific device  Loads each time you boot the computer  Needed by the mouse, keyboard, monitor, printer, card reader, scanner, etc.

Establishing an Internet Connection  Some systems include a web browser and program

Monitoring Performance  Program that assesses and reports information about various computer resources and devices  Used to monitor  Processor  Disks  Memory  Network usage  Used to identify problems and resolve problems

Administering Security  Assign User ID’s or User Name  Use Passwords  Prevents unauthorized users from accessing computer resources  Records successful and unsuccessful logon attempts

Operating System Utility Programs  Utility Program  Allows a user to perform maintenance-type tasks

Utility Programs  File manager  Formats and copies disks  Displays list of files on a storage medium  Checks the amount of free space  Image Viewer  Displays and copies the contents of a graphics file  Allows the user to see the image without opening Paint or another image editing program

Utility Programs  Uninstaller  Removes programs along with any associated files  Disk Scanner  Detects and corrects physical and logical problems on the hard disk or floppy disk  Searches for and removes unnecessary files

Utility Programs  Disk Defragmenter  Reorganizes the files and unused space on a computer’s hard disk  Allows the operating system to access data more quickly and programs to run faster  Reorganizes files so that they are stored in contiguous sectors  Diagnostic Utility  Complies technical information about the computer’s hardware and certain system software programs and then prepares a report outlining any identified problems  Suggests courses of action to resolve problems found

Utility Programs  Backup Utility  Allows users to copy selected fields or an entire hard disk onto another disk or tape  Many compress the size of files to use less storage space  Screen Saver  Displays a moving image if there is no keyboard or mouse activity for a specified period of time

Types of Operating Systems  Device –Dependant  Runs only on a specific type of computer  Proprietary software  Privately owned and limited to a specific vendor or computer model  Device-Independent  Run on computers provided by a variety of manufacturers  Allows you to retain existing application software and data files even if you change computer models or vendors

Three Categories of Operating Systems  Stand-alone  DOS, Windows, Mac OS X, OS/2 Warp Client, Unix, Linux  Network  Netware, Windows server, OS/2 Warp Server for e- business, UNIX, Linux, Solaris  Embedded  Windows CD. NET, Pocket PC 2002, Palm OS, Symbian OS

Three Categories of Operating Systems  Stand-Alone  Complete operating system that works on a desktop computer, laptop, or mobile computing device  Sometimes called, Client operating systems  Network Operating System  Designed specifically to support a network  Resides on a server  Work with Client operating systems

Three Categories of Operating Systems  Embedded Operating Systems  Used in most PDA’s  Resides on a ROM chip

Stand-Alone Utility Programs  Antivirus Programs  Protects a computer from being infected by a virus or worm or removes any that are found  Personal Firewalls  Detects and Protects a personal computer from unauthorized intrusions.  Monitor all transmissions to and from a computer

Stand-Alone Utility Programs  File Compression  Shrinks the size of a file  Takes up less disk space then the original file  Personal Computer Maintenance  Identifies and fixes operating system problems  Detects and repairs disk problems