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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 e-mail
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.
Thanks For Your Time!!