Transcript Operating System

Type of Software
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There are two main types of software
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They are
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System software
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Application software
Application Software (Word, Excel)
System Software (OS)
Hardware
System Software
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System software is computer software designed to
operate the computer hardware and to provide a
platform for running application software
System software also provides services to computer
users and application programs
Examples of system software are: operating system,
device driver and utility programs
Operating System
Printer Driver
Hard Disk Analyzer
Operating System Function I
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Provide user interface (text interface and/or graphical
user interface)
Execute application (automate the process to run a
program, loading program into main memory, transfer
control to CPU, etc)
Manage CPU time (allocate CPU time to different
processes to achieve multitasking)
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Multitasking refers to the ability to run two or more
tasks at the same time
Memory management (allocate memory to different
processes so as to maximize system performance)
Operating System Function II
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Manage I/O (peripheral) devices such as
keyboard, mouse, monitor, network interface
card, etc
Provide system accounting service (logging,
CPU and /or disk usage)
Provide system security (by using user name
and password)
Application Program
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Application program is designed to solve a
particular kind of problem
Examples of application program:
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Word processor (Word)
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Spreadsheet (Excel)
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Graphic Editor (Photoshop)
Software (Rights)
• Software can be classified according to the
rights that come with the software
• There are 4 main types of software in this
category:
– Proprietary software
– Shareware
– Freeware
– Open source software
Proprietary Software
• Proprietary software is computer software that
gives the legal right to use the software to
customer under restrict conditions.
• Conditions include:
– Re-distribution is not allowed
– Re-sell is not allowed
– Modification is not allowed, etc
– Example:
Shareware
• Share is similar to proprietary software except that it
can be downloaded from the internet with a trial period
• During the trial period, customers can use the software
for free
• Customer should (must?) pay for the software if he/she
wants to continue to use the software after the trial
period
• Examples:
Winzip (Utility)
Window Media Player (Application)
Freeware
• Freeware is completely free of charge
• It can be downloaded from the Internet
• However, users are only given the right to use
the software, users are not allowed to modify
and/or resell the software
• Example:
AntiVirus Utility
Open Source Software
• Open Source Software gives all rights to users
• Users can get the source code which can be
used to modify the software
• Users can re-distribute open source software (or
even re-sell it!)
• Example:
Office Suite
Graphic Editor
Mode of Operation
• Mode of operation refers to how computer system
reacts to input data
• Batch Processing vs Real-time Processing
• When data are accumulated and processed only at a
certain time (say once a week or once a month), this
type of processing is called batch processing
• Example application:
Electricity Bill,
Credit Card Bill, etc
Real-time Processing
• In real-time processing, data must be
processing within a very short period of time
• Example application:
Ticker Booking
(Air ticket,
Cinema ticket,
etc)
Interactive Processing
• Interactive processing refers to the processing
of data that requires feed back from users
• Example:
ATM (automatic teller
machine)
-It works interactively
(real-time!)
-Question:
Are all real-time
processes must be
interactive?