Chapter 8: Operating Systems and Utility Programs Catherine Gifford Dan Falgares

System Software Two Types –Operating Systems Set of instructions that coordinate all activities among computer hardware resources. Most perform following functions: –Starting a computer –Managing programs –Managing memory –Internet connection –Utility Software Type of software that allows a user to perform maintenance types of tasks, usually relating to managing a computer’s devices or programs.

Operating Systems (OS) Functions –Starting a Computer Each time you boot your computer a operating system known as the kernel is used to: –Load instructions from the hard disk to the computers memory (RAM). –Manages memory and devices –Maintains the computers clock –Starts applications –Assigns computers programs such as devices, programs, data, and information.

Operating Systems User Interface: controls how you enter data and instructions, and how information is displayed on the screen. Three types of interfaces: –Command-line When a user types commands or presses special keys to enter data or instructions Difficult to use –Menu driven Menus as a means of entering commands Easier to use then command-lines. No need to learn the rules of entering commands. –Graphical Most widely used Interact with menus and visual images such as buttons and other graphical objects to enter commands. –I.e.: Back and forward button.

Managing Programs Single user single tasking –Allows one user to run one program at a time –PDAs and other small computing devices use a single user/ single tasking operating system Single user multitasking –A single user can work on two or more programs at the same time –Foreground –Background Preemptive multitasking –An advantage to preemptive multitasking would be control factors, because it controls how the computer uses its memory –Used for larger systems

Managing Programs cont. Multiuser –Enables two or more users to run programs at the same time, i.e. networks Multiprocessing –Operating system supports two or more processors running programs at the same time Fault-tolerant computer –Computer with a separate processor –Continues to operate when one of its components fail, no loss of data –i.e. airline reservation systems

Managing memory Memory management –To optimize the use of random access memory (RAM) Virtual memory –The operating system assigned a portion of storage medium, i.e. a hard disk, to function as additional RAM –Slower than RAM –Swap file The part of the hard disk used for virtual memory Paging is the technique of swapping items between memory and storage –It’s a time consuming process

Scheduling jobs Buffer –A holding zone of memory in which items are placed while waiting to be transferred from an input device or output device Spooling –Sends print jobs to a buffer instead of directly to the printer –This enables users to work on other tasks on the computer while printing Queue –Multiple print jobs lined up in a buffer

Configuring devices Driver –Short for device driver, it’s a small program that tells the operating system how to communicate with a specific device –Each device on the computer, i.e. mouse and keyboard requires its own specific driver Plug and play –Operating system automatically configures devices as you install them –Makes installation easier

Establishing an internet connection Operating systems provide a way to establish connection. –Some include a web browser and program Performance Monitor –program that assesses and reports information about various computer resources.

Controlling a network Network Operating System: –Organizes and coordinates how multiple users access and share resources on a network. Include Hardware, Software, data, and information When not on network user uses their own operating system

Utility Programs Def: –Type of system software that allows a user to perform maintenance-type tasks, usually related to managing a computer. Most operating systems include several utility programs –Utility Programs File Manager Image Viewer Uninstaller Disk Scanner Disk Defragmenter Diagnostic utility Backup Utility Screen Saver

Utility Programs File Manager –Performs tasks related to file and disk management Image Viewer –Allows users to display and copy contents of a graphic file Uninstaller –Utility that removes a program

Utility Programs Disk Scanner –Utility that detects and corrects both physical and logical problems on the hard disk and floppy disk –Removes unnecessary files Disk Defragmenter –Reorganizes the files and unused space on the hard disk, to allow programs to run faster.

Utility Programs Diagnostic Utility –Compiles technical information about your computer’s hardware, then prepares a report outlining any problems. Backup Utility –Allows users to copy or back up selected files or an entire hard disk. Screen Saver –Developed to prevent a problem called ghosting

Types Of Operating Systems Three Types –Stand-alone –Network –Embedded

Stand-Alone Def: –Complete operating system that works on a desktop computer, notebook computer, and mobile device. Examples: –DOS –Windows XP –Mac OS X –UNIX –Linux

Network Def: –Designed specifically to support a network Examples –NetWare –Windows Server 2003 –Unix –Linux –Solaris

Embedded Def: –Operating system on most PDA’s and small devices, it resides on the ROM chip. Examples –Windows CE.NET (most popular) –Windows mobile 2003 –Palm OS –Symbian OS

Stand Alone Utility Programs Anti-virus programs Personal Firewalls: –Utility program that detects and protects a personal computer from unauthorized intrusions File Compression: –Shrinks the size of a file Personal computer maintenance –Identifies and fixes operating system problems, disk problems, and has the capability of improving a computers performance.

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