Transcript Working with Images - Faculty of Computer Science and

COMPUTER SOFTWARE
EDIT Module 1: Introduction to
Information Technology
Think of a computer as a robot.
What do you want it to do?
We Want a Computer To:
1. Read input data from source documents or
secondary storage.
2. Process the data.
3. Display the results.
4. Print the results.
5. Store the results.
6. Transmit the results.
7. Protect itself and the data.
8. Keep track of things that it is doing to restart.
9. Count things to reflect performance.
10. Do multiple things at the same time.
For the computer to be able to
perform all these requires the
user to instruct the computer
software to control the machine
Why is this topic important
Hardware is the engine and software is the
gas that makes it run.
 To understand software concepts is to
understand how real work gets done on
computer-based systems within a business.
 To understand software is to appreciate the
specific details that must be addressed for a
new computer-based application to be
implemented.

Important Topics

Major categories of software.

The importance of operating systems and related
systems software.

The increasing importance of application
packages.

Challenges to implement application packages.

The evolution of programming languages and the
reason for so many languages.
Computer Software
The detailed instructions that control
the operation of a computer system.




Provide tools to people.
Intermediary between people and data.
Manage the computer resources.
Selecting appropriate software for an
enterprise is a key management decision.
Overview of Computer Software
Computer
Software
System
Software
Application
Software
GeneralPurpose
Programs
ApplicationSpecific
Programs
System
Management
Programs
System
Development
Programs
Trends in Computer Software
First
Generation
Second
Generation
Third
Fourth
Generation Generation
Fifth
Generation
Trend: Toward Easy-to-Use Multipurpose Network-Enabled Application
Packages for Productivity and Collaboration
User-Written
Programs
Machine
Languages
Packaged
Programs
Symbolic
Languages
Operating
Systems
High-Level
Languages
DBMS
FourthGeneration
Languages
Microcomputer
Packages
Natural &
Object-Oriented
Languages
Multipurpose
Graphic- Interface
Network-enabled
Expert-Assisted
Packages
Trend: Toward Visual or Conversational Programming Languages and
Tools
Application Software:
End User Applications
1) General Purpose Application Programs

Software Suites – Microsoft Office
– Word Processing - Word / Works / Claris
– Spreadsheet – Excel / FoxPro / Lotus
– Database Managers - Access / Dbase/Sybase



Web Browsers – Internet Explorer / Netscape
Electronic Mail – MS Outlook / Express /
Eudora
Presentation Graphics – Power Point / Flash
Application Software:
End User Applications
2) Application-Specific Programs

Application Software Packages support
managerial and operational uses:
–
–
–
–
Accounting
Transaction Processing
Customer Relationship Management
Electronic Commerce
System Software:
Computer System Management
1) System Management Programs
• Operating System
- Resource Management
- File Management
- Task Management
• Network Management Programs
• Database Management Systems
• System Utilities
System Software:
Computer System Management
2) System Development Programs
• Programming Language
- BASIC / C++ / COBOL / JAVA/TURBO-PASCAL
• Programming Translators
- Assemblers – translates assembler language
- Compilers – translates high level language [translate
the program (source code) into machine code (object code), then
execute the object code.]
Programming Languages
Machine Languages High Level Languages Markup Languages
Use binary coded
Use brief statements
Use embedded
instructions
control codes
1001 1001
<H1>First heading</H>
Compute X = Y + Z
<!ELEMENT Product
1100 1101
(#Item | manuf)>
Assembler Languages Fourth Generation
Object-Oriented
Use symbolic coded Languages
Languages
Use natural statements Define objects that
instructions
LOD Y
ADD Z
SUM THE FOLLOWING
NUMBERS
contain data and actions
Document.write
(“Hi There”)
In short:


– Five basic functions:
»
»
»
»
»
Software
– Application vs. System

Application Software
– General purpose
applications for end
users

System Software
– Manage hardware,
software, network, data
resources
Operating Systems

User interface
Resource Management
File Management
Task Management
Utilities for support
services
Programming
Languages
– Five major levels:
»
»
»
»
»
Machine language
Assembler language
High-level language
Fourth-Generation
Object-Oriented
Systems Software

Definition:
– All programs related to coordinating
computer operations

Components
– Operating System
– Utility programs
– Program language translators
Operating System
Hidden Software


Definition – provides access to all resources
Kernel
– Manages the operating system
– Memory resident
– Loads set of programs that lies between applications
software and the hardware
– Fundamental software that controls non-resident portions of
the OS as needed

Booting – Loads the kernel into memory
Operating System
A software program that acts as an intermediary
between a user of a computer and the computer
hardware.
Exist because it is a reasonable way to solve the
problem of creating a usable computer by better
managing the computer resources.
The basis for standardization of application
software. (the platform)
Functions of an Operating System
User
Interface
Resource
Management
Use of
hardware
resources
Task
Management
Managing the
accomplishment
of tasks
File (Data)
Management
Utilities
and Other
Functions
Managing
Data and
Program Files
Sort, Merge,
Performance,
etc.
Functions of OS

Manage the computer’s resources
–
–
–
–
CPU
Memory
Disk drives
Printers

Establish a user interface

Execute and provide services for applications
software

Carries out all input and output operation
Operating System Functions
Multiprogramming - executing two or more
programs concurrently using the same computer.
Multiprocessing - executing two or more
instructions simultaneously in a single computer by
using multiple central processing units.
Graphical User Interface (GUI) - part of the
operating system that uses graphic icons to issue
commands and make selections.
User Interface

Facilitates communication between the user and
the operating system

Two forms
– Command line
» Text-based
» Key commands
» Examples: MS-DOS, Unix
– Graphical user interface (GUI)
» Visual images
» Menus
» Examples: Windows, Mac OS, Linux
Popular Operating Systems
• DOS

UNIX
• Windows .X

Linux

OS/2

Mac OS

IBM MVS, VM
• Windows NT
OS is Hidden

User interested in application
software to make the PC
useful

Application software is
platform specific

User must be aware of the
type of OS

User should be aware of the
functions of OS
What is the platform of your
system?
A common question posed to a
system vendor, manufacturer or even
the organization utilizing the
system…..
Platform

Definition:
Computer hardware and operating
system software that dictate what other
software can run

E.g. Wintel
Intel-based PC running on
Microsoft Windows
Types of OS
Command line
Single user PC
Network Operating System (NOS)
Command-line: MS-DOS

Command-line interface

Prompt – system is waiting for you to do
something

Key a command

Not user-friendly
Single-user PC:
Microsoft Windows

Graphical user
interface

Eases access to
the OS

Most new
computers come
with Windows
already installed
Network Operating System
NOS


Designed to permit computers on a network
to share resources
Examples
– Windows 2000 Server
– Novell Net Ware

Provides
– Data security
– Troubleshooting
– Administrative control
NOS Functions


Split between client and server computers
Server
– File management

Client
– Requests to the server
– Messaging
– Has own local OS

Makes the resources appear as if they are
local to the client’s computer
Early Days of Windows OS
Operating environment for MS-DOS
Shell – layer added between users
and DOS
Windows Today

Home/consumer market
– Windows 95
– Windows 98
– Windows Millennium Edition (ME)

Corporate market
– Windows NT
– Windows 2000


Windows XP
Pocket computers and Internet appliances
– Windows CE
What are the prominent features
of Windows?
Prominent feature of
Windows: GUI

On-screen pictures
– Icons
– Menus
» Pull down
» Pop up
– Click to activate a
command or function



Fast
Easy
Intuitive
Windows 95 and 98



Self-contained OS
DOS commands still available
Start programs by
– Start button
– Double clicking the icon




Task bar permits movement between open
programs
Long file names up to 255 characters
Plug and play
Object linking and embedding (OLE)
Windows 98 Additions

Internet / intranet browsing

Support for DVD and additional
multimedia components

Support for large hard drives

TV viewer and broadcast ability

Wizards / Help Assistant
Improved Windows Features
Backup
 Interfaces with other software
 Networking features
 Security
 Dr. Watson

Windows
Helps reduce the cost of owning and
maintaining a PC
Windows ME
Millennium Edition
Multimedia support -- Windows Media Player 7

Jukebox
– Record music CDs as digital files

Windows Movie Maker
– Basic video editing

Windows Image Acquisition
– Scanner and digital camera
Windows ME
Millennium Edition

Reliability Features
– System File Protection
– AutoUpdate
– System Restore


Help Center
Home Network Support
– Wizard for connecting multiple computers and
peripherals
– Multiple users can share a single Internet
connection
Windows NT
New Technology



Engineered for stability
Strong security
Versions
– NT Workstation
– NT Server

Drawbacks
– Lacks support for older Windows and MS-DOS
software and hardware
– Complex to learn and use
– Requires more memory and processing power
Windows 2000




Stability features
Security features
Uses simple approach to hardware setup
from Windows 98
Versions
– Windows 2000 Professional for individual users
– Windows 2000 for network servers

Was intended for both the corporate and
home use, replacing Win NT and Win 98
Windows 2000

Complex

Heavy demand for computer resources

Improvements over windows NT
–
–
–
–
–
Maintains user preferences
Self-healing applications software
Supports Windows 98 file structure
Uses plug and play
Provides improved support for laptops
Windows XP

Extends Windows ME and provides a
more stable environment

Two categories
– Network server
» 3 versions based upon network complexity
– Desktop computer
» 2 versions


Professional Client
Personal Client
Windows CE
Consumer Electronics
Where used

Embedded systems
–
–
–
–
–
–
–


Industrial controllers
Robots
Office equipment
Cameras
Telephones
Home entertainment devices
Automobile navigation systems
Pocket PC
Internet appliance market
Windows CE
Consumer Electronics
Subset of Windows

Less memory

Smaller screens

Little or no file storage

Provides Internet connectivity
Mac OS

First
commercially
successful GUI
(1984)

Served as a
model to other
GUI systems
UNIX

Supports
– Multi-user
– Time-sharing
Character-based system
 Command-line interface
 Runs on various processors and many
types of computers
 Primary OS used on Internet servers

LINUX


UNIX-like OS
Open-source software
–
–
–
–

Download it free
Make changes
Distribute copies
Restriction – any changes must be freely
available to the public
PC Setup
– PC comes with Windows installed
– Install LINUX in a dual-boot configuration
LINUX

Advantages over Windows
– Extremely stable
– Internet support
– Reinstallation is simpler

Disadvantage
– Scarcity of applications
Large Computers
Used by many people at once
 OS works “behind the scenes” so users
can share resources (hardware &
software)
 OS must control

– Who gets access to resources
– What keeps the programs from different
users from getting mixed up with one
another
Sharing Memory

Program must be in memory to be
executed

Problems
– Programs compete for space
– May have a very large program
– Memory space for each program must not
overlap
Memory Management

The process of providing separate
memory space to programs

Memory Protection keeps one
program from interfering with another
Sharing Storage

Several users need to access the same
disk pack
– One wants to write
– Another wants to read

OS keeps track of the I/O requests

OS processes I/O requests in order
received
Utility Programs




Come with System Software
Handle special needs
Perform secondary chores
Do not need to be memory resident
Functions of Utility programs





File manager – provide access to lists of stored files
Backup and Restore – make duplicate copies of
important files and return the copy to the hard drive if
needed
File compression – reduces the amount of disk
space required by a file
Disk defragmenter – reorganize files so they are
stored contiguously on disk providing for faster
access
Device drivers – convert operating system
instructions into commands that are known to a
specific device
Are all operating systems the same?

Features and functions.

Advantages and benefits.
From Personal Computers to Mainframes?
Summary
Operating systems are the foundation of a
computer operation.
Operating systems benefits include better resource
utilization, better system performance, gains in costeffectiveness and better overall management of the
entire system.
Without operating systems with advanced features
and functions, computing would still be in its very
early stages.