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!!