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Operating System
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A collection of programs foroperating the computer.
Operating
systems perform housekeepingtasks such as input/output
between
the computer and peripherals,
and accepting and interpretinginformation from the keyboard.
Operating System
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S yS o
A p pS o
S o
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Operating Systems
Operating systems tell the computer how toperform the functions
of loading, storing, and
executing an application program and how to
transfer data.
Controls all the computer's resources and
provides the base upon which the applications
programs can be written.
Most operating systems use a Graphical UserInterface (GUI) that
provides visual cues such as
icon symbols to help users interact with and
navigate the operating system
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Computer Software
Relationships
User
Interface
Basic Input and Output Services (BIOS)
needed for a computer to boot up
User Interface Operating System
User Interface Application Programs
Computer Hardware
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Basic OS Tasks
Operating
System
Userinterface
Device management
Mem
orym
anageme
nt
Processormanagement
Applicat
ionman
agement
Operating
System
Userinterface
Device management
Mem
orym
anageme
nt
Processormanagement
Applicat
ionman
agement
Operating
System
Userinterface
Device management
Mem
orym
anageme
nt
Processormanagement
Applicat
ionman
agement
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Operating System
Functions
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OS Functions
Starting a computer
Providing User Interface
Managing Programs Managing Memory
Configuring Devices
Monitoring Performance Controlling Network
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Plug and Play
A helpful part of the operating system thatallows for the
addition of new devices
such as sound cards or scanners
The operating system detects devices asthey are plugged in and
configures the
computer automatically to allow instant
play
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Operating System Definitions
These definitions could be in other words thefeatures an OS has
to perform in an overall
computer system
Resource allocator manages andallocates resources.
Control program controls the executionof user programs and
operations of I/O devices
Kernel the one program running at alltimes (all else being
application programs).
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Resource Allocation
Resource allocation is the process ofassigning computer
resources toprograms
Two ways to share the CPU Multiprogramming
Time-sharing
Similar sounding, multiprocessing refers toa computer with more
than CPUs
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Multiprogramming
Two or more programs running at the same
time, or concurrently
The programs take turns with the processor.
They are using the CPU in the same time frame,but not in the
same instant
For example, your operating system may use
the CPU to load your email program while
Microsoft Word is saving something to disk
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Characteristics of Modern
Operating Systems New design elements were introduced
recently
In response to new hardware development
multiprocessor machines high-speed networks
faster processors and larger memory
In response to new software needs
multimedia applications
Internet and Web access
Client/Server applications
