Basic Computer Concept in Computer Science

8/9/2019 Basic Computer Concept in Computer Science

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Data Representation and

Digital Electronics

Data Representation

makes it possible to convert letters,

sounds, and images into electrical signals

Digital Electronics

makes it possible for a computer to

manipulate simple on and off signals

to perform complex tasks


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Digital Data

Representation

Why are computers digital ?

Digital Device works with discrete -distinct or separate -

data or digits, such as 1 and 0

Analog Device

works with continuous data

Computers are digital because computer

designers have found it to be a relatively

simple, dependable, and adaptable

technology.

A digital computer is a simpler technology

than an analog computer. Most computers use the simplest type of digital

technology, their circuits have only two

possible states.


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Digital Data

Representation

How can a computer represent numbers usingbits ?

Computers represent numeric data using the

binary number system, also called base 2

Numeric Data

the numbers that might be used in

arithmetic operations

Binary Number System

has only two (2) digits : 0 and 1

allows computers to represent virtually anynumber simply by using 0s and 1s

conveniently translates into electrical on

and off signals


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Digital Data

Representation

How can a computer represent words andletters using bits ?

Character Data

consists of letters, symbols and numerals

that will not be used in arithmetic

calculations

A digital computer uses a series of bits to

represent letters, characters, and numerals.

ASCII

pronounced as ASK ee

stands forAmerican Standard Code for

Information Interchange

requires only seven bits for each character

Extended ASCII

a superset of ASCII

uses eight bits to represent eachcharacter

provides codes for 128 additional

characters


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Digital Data

Representation

How can a computer represent words andletters using bits ?

EBCDIC pronounced as EB seh dick

stands for Extended Binary Coded Decimal

Interchange Code

an alternative 8-bit code usually used by

IBM mainframe computers

UNICODE pronounced as YOU ni code

provides codes for 65,000 characters and

makes use of 16 bits


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Digital Data

Representation

How does a computer convert sounds andpictures into codes ?

A computer must somehow digitize colors,notes, and instrument sounds into 1s and

0s, in order to work with sounds and

pictures.

Computers convert colors and sounds into

numbers, which can be represented by

bits.

A red dot on your computer screen might

be represented by 1100, a green dot by

0010.


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Digital Data

Representation

When a computer works with a series of 1s and0s, how does it know which code to use?

All of the things that computer works with isstored in files as a long series of 1s and 0s.

The computer needs to know whether to

interpret those 1s and 0s as ASCII code, binary

numbers, or the code for a picture or sound.

Most computer files contain a file header with

information on the code that was used torepresent the file data, to avoid confusion.

A computer can now tell how a files contents

were coded by reading the header information.


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Digital Electronics

How can I tell the difference between bits andbytes?

bit binary digit

can be further abbreviated as a lowercase

b

byte

composed of eight (8) bits

usually abbreviated as an uppercase B

nibble

composed of four (4) bits

a halfway between a little bit and a big

byte

Storage space is usually expressed in bytes

while transmission speeds are expressed inbits.


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Digital Electronics

How does a computer store and transport all ofthose bits ?

Bits take the form of electrical pulses that can

travel over circuits.

The circuits, chips, and mechanical

components forming a computer are designed

to work with bits.

These components are housed within thecomputers system unit.


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Digital Electronics

How do chips fit together to make a computer?

otherboard

also known as main board

the computers main circuit board

houses all essential chips and provides

connecting circuitry between them

Some chips are permanently soldered in place,

while other chips are plugged into special

sockets and connectors. The chips might be gathered together on a

separate small circuit board, which can then

be plugged into a special slot-like connector.


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Microprocessor Basics

Microprocessor

sometimes known as rocessor

an integrated circuit designed to process

instructions the most significant component of

computer and usually the most expensive

single component

executes instructions that are provided by

a computer program

Instruction Set list of instructions that a microprocessor

can perform

hardwired into the processors circuitry

comprising of basic arithmetic and logical

operations, fetching data, and clearing

registers

Memory

is the electronic that holds place for

instructions and data which the

microprocessors can reach quickly


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Todays Microprocessors

Which companies produce most of todayspopular microprocessors ?

Intel worlds largest chipmaker and supplies a

sizeable percentage of the

microprocessors that power personal

computers

introduced the worlds first

microprocessor , the 4004, during 1971 AMD (Advanced Micro Devices)

Intels chief rival in the PC chip market

produces microprocessors that work just

like Intel's chips, but a lower price


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Todays Microprocessors

Which of the microprocessors is the best ?

Intel

Original Pentium : 1993

Pentium II : 1997

Pentium III : 1999

Pentium IV: 2000

Itanium : 2001

Celeron processors : Intels budget model

AMD

Athlon processors : Direct competitors to

Intels Pentium line

Duron processor : AMDs budget model

The microprocessor thats best for you

depends on your budget and the type of work

and play that you plan to do.


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Components of DataProcessing

Data processing is a technique of collecting,

manipulating and distributing data to achieve

certain functions

Objective: to convert raw data intoinformation that can be used in decision

making

Computer Systems

A system is a collection of objects,

procedures, or techniques that

interact in regulated manner to form

an organized whole


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Central Processing Unit (CPU)

integrates and coordinates overall

operations

composed of three (3) units:

The CPU sub-units: ALU, Control Unit andPrimary Storage


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Central Processing Unit (CPU)

Control Unit

maintains order and controls activity in the

CPU does not process or store data but it

directs the sequence of operations

interprets the instructions of a program in

storage and produces signals that act as

command circuits to execute the

instructions Arithmetic/Logic Unit (ALU)

performs arithmetic computations and

logical operations

Primary Storage Unit

holds instructions, data, and intermediate

and final results

a reusable, fast storage medium, directly

accessible by the control unit


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Input/Output Subsystem

provides the mechanism for

communications between the CPU and the

outside world input subsystem - reads data and

converts them into electronic pulses

output subsystem - reports the results ofthe processing by the CPU

Memory Subsystem

also known as the secondary storage,allows for extra data storage, exceeding

the CPUs primary storage

an efficient and compact means of sorting

large amount of data, ready for retrieval or

further processing

retrieval time is slower than the primary

storage


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I/O Components

Common I/O Peripherals

Keyboard

Mouse

Monitor

Hard disk

Printer


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I/O Components

Other I/O Devices

CD-ROM drive

Modem

Sound Card

Scanner


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Storage Components

Memory

Random Access Memory (RAM) is a type ofcomputer memory chip that allows instructions

and data to be stored, changed and retrievedby the user

Read Only Memory (ROM) is a memory chipthat allows only readout capability

Programmable Read Only Memory (PROM)enables the user to add special information to

the ROM supplied by the manufacturer as part

of the system

Virtual Memory is an imaginary memory areasupported by the software in conjunction with

the hardware


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Storage Components

Mass Storage Device

Floppy Disks

Compact Disk (CD)

Zip Disk


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Classification ofComputers

Minicomputers, Microcomputers andMainframes

Microcomputers are small desktop systems

with limited I/O devices --- usually only akeyboard for input, a floppy disk for

storage, and a monitor for output

Minicomputer is a general-purposecomputing device, either rack-mounted or

small enough to fit in a desktop

Mainframe is a very large and expensivecomputer capable of supporting hundreds,

or even thousands of users simultaneously

Desktop PCs

medium sized computers

relatively inexpensive and designed for

individual users


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Classification of PCs

Supercomputers

fastest type of computers

very expensive and are employed for

specialized applications that require heavymathematical calculations that smaller

computers may not be able to do

weather forecasting

animated graphics

fluid dynamic calculations

nuclear energy research RISC vs. CISC

Reduced Instruction Set Computer (RISC)

Complex Instruction Set Computer (CISC)


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Software, Programs and

Support Modules Software

comprises of computer programs , support

modules, and data modules that work

together in order to provide a computer

with the instructions and data necessary

for carrying out a specific type of task

Program

a set of instructions that tells a computer

how to solve a problem or carry out a task

Support Module

provides an auxiliary set of instructions

that can be used in conjunction with the

main software program

not designed to be run by the computer

user


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Software, Programs and

Support ModulesWhy does a software requires so many files?

Most software packages include at least one

executable program file, several support

modules, and one or more data modules.

It is for the programmers great deal of

flexibility and efficiency.

Most of the support modules contain generic

program instructions that can be used to work

with various programs.

These techniques affect the process ofinstalling and uninstalling software.


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How Software WorksHow does a high-level language relate to the

microprocessors instruction set?

Machine language is the only language that can

be understood by a computers

microprocessor.

Instructions written in a high level language

must be translated into machine language

before a computer can use them.

A special type of programs called translators,

convert instructions from a high-level language

into machine language.


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How Software WorksAssuming that a VideoFactory, a video editing

program, was installed on your computer,

which is running Windows.

You click the Start button, then select

VideoFactory from the Programs menu.

The instructions for Vidfact.exe are loaded

into RAM and then sent to the microprocessor.

The VideoFactory window opens and the

graphical controls for video editing tasks

appear. The programs wait for you to select a

control by clicking it with the mouse.

The program follows its instructions and

performs a pre-specified action.

The program continues to respond to the

controls that you select until you click the

Close button, which halts execution of the

program instructions and closes the program

window.


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Operating System

What does an operating system do

A computers software acts similarly with the

chain of command in an army.

Using application software, you issue a

command.

Application software tells the operating

system what to do.

The operating system instructs the device

drivers, device drivers instruct the hardwareand the hardware actually does the work.


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Operating System

What does an operating system do

The operating system interacts withapplication software, device drivers, and

hardware to manage a computers resources.

While interacting with application software,

operating system is busy behind the scenes

with other tasks.


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Operating System

How does an operating system affect the lookand feel of application software?

An operating system typically provides userinterface tools, such as menus and toolbar

buttons, that define the look and feel for all

of its compatible software.

Apple computer released its popular Macintosh

computer in 1984, which featured a GUI

operating system and applications.

During 1992, when Windows 3.1 became

standard issue on most PCs, GUIs did catch on

in the PC market, replacing a command-line

interface that had given many people a string

aversion to computers in general.


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Operating System

Where is the operating system

The entire operating system is small enough to

be stored in ROM for typically handheld

computers and video game consoles.

For nearly all personal computers, servers,

workstations, mainframes, and

supercomputers, the operating system program

is quite large, so most of it is stored on a hard

disk.

The bootstrap program provides theinstructions needed to load the core parts

(kernel) into memory when the system boots.

Customization utilities and other parts of the

operating system are loaded into memory as

they are needed.


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Operating System

Do I ever interact directly with the OS

Launch programs

Customize the user interface

Manage Files

Configure Equipment

Get Help


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Operating System

re different operating systems needed fordifferent computing tasks ?

Single-user operating system deals with one set of input devices, those

that can be manipulated by one user at a

time

Multi-user operating system

deals with input, output, and processing

requests from many users , all at the sametime


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Operating System

re different operating systems needed fordifferent computing tasks?

Network operating system

provides communications and routing

services that allow computers to share

data, programs and peripheral devices

Multitasking operating system

provides process and memory managementservices that permit two or more programs

to run simultaneously


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Operating System

re different operating systems needed fordifferent computing tasks

Desktop operating system

designed for a personal computer, either a

desktop or notebook computer

designed to accommodate a single user,

but may also provide networking and

multitasking capabilities


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Windows, MAC OS,Linux, UNIX and DOS

Whats the best-selling operating system?


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Is Mac OS similar to Windows?

Both operating systems base their user

interfaces on the graphical model that was

originated at Xerox PARC, although Mac OS wasdeveloped several years before Windows

Mac and Windows interfaces use a mouse to

point and click various icons and menus

re UNIX and Linux the same?

UNIX, developed in 1969 at AT & Ts Bell Labs,gained a good reputation for its dependability

in multi-user environments

Linuxwas developed in 1991, based on a

version of the UNIX kernel called Minix

Linux is considered to be a popular operating

system for e-mail, web-servers and local area

networks


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Why do I keep hearing about DOS?

stands for Disk Operating System

it provides part of the operating system kernelfor Windows versions 3.1, 95, 98 and ME

users rarely interact with DOS, because it is

well hidden by the Windows graphical user

interface


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Software

Software: can be divided into:

systems software or system programs

applications software or application

programs Types of Computer Software


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Functions of anOperating System

Operating Systems

collection of system programs and routines

that reside in the computers memory

functions:

Schedule input and output operations

Schedule work of jobs according to

priority

Communicate with the human operator

Handle interruptions and monitor

system status

Log the jobs that are finished and

currently being executed

Control system access and data

security functions

Facilitate in locating and debugging

errors Handle multiprogramming, so that

several programs can run at the same

time


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Functions of anOperating System

Operating Systems

stored in a secondary storage device known

as a system residence device

in the early days when magnetic tape

drives are still used as storage devices,

operating systems that are stored in

magnetic tapes are called Tape OperatingSystems

if the operating system is stored in a

magnetic disk it is called a Disk OperatingSystem (DOS)


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Structure of anOperating System


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Programs that Make Upan Operating System

Control Programs - manage the overallsystem operations and perform tasks such

as scheduling, input/output handling,monitoring of system status and

communication with the programmer

Supervisor Program

Input/Output Control System

Service Programs - are subprograms orroutines that are frequently used by the

programmer

Language Translator Programs

Librarian Programs

Utility Programs

Diagnostic Programs


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Survey of an OperatingSystem

MS-DOS

The Windows Family of Operating

Systems Windows 1.0, 2.0, 3.1 and 3.11

Windows NT and Windows 2000

Windows 95, 98, ME and XP

UNIX and Linux


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Microsoft Windows is being used on over 80percent of the worlds personal computers.

Windows has evolved through several versions,

since its introduction.


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Windows 95, Windows 98, Windows ME andWindows XP provide basic networking

capabilities, making them appropriate for

small networks in homes and businesses.

Windows NT, Windows 2000, and Windows XP

Professional are typically classified as server

operating systems.


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Is Mac OS similar to Windows?

Both operating systems base their user

interfaces on the graphical model that wasoriginated at Xerox PARC.

Both Mac and Windows interfaces use a mouse

to point and click various icons and menus.

Both also provide basic networking

capabilities.

Though the selection is not as vast as thecollection of Windows, a collection of software

is available for computers that run Mac OS.


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UNIX gained a good reputation for itsdependability in multi-user environments.

Many versions of UNIX became available for

mainframes and microcomputers.

Linux is distributed under the terms of a

General Public License (GPL), allowing

everyone to make copies for their own use, togive others, or to sell.


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Linux shares several technical features withUNIX.

Linux is considered to be a popular operating

system for e-mail , web-servers and local area

networks.

Linux has been gaining popularity as a desktop

operating system.


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Why do I keep hearing about DOS?

DOS was the first operating system and its

cryptic command-line user interface left anindelible impression.

The remnants of DOS still linger in the world of

personal computers, because it provides part

of the operating system kernel for Windows

versions 3.1, 95, 98 and ME.

Users rarely interact with DOS, because it iswell hidden by the Windows graphical user

interface.

DOS is nothing more than footnotes in the

history of the computer industry.


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Application Software

An Overview of Application Software

Word Processing

a term used in manipulating text or wordsin a file

Basic features: insert text

delete text

cut and paste

copy

page size and margins

search and replace

word wrap Print

Advanced features: file management

font specifications

footnotes and cross-references

graphics

headers, footers, and page numbering layout

merges

spell checker

tables of contents and indexes

thesaurus

windows

WYSIWYG


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Microsoft Word


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Spreadsheet

computer programs especially designed to

display information graphically and allow

files and data to be manipulated easily an electronic ledger sheet on which data

are entered

MS Excel Spreadsheet Program


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Database Management

application software packages that

computerize the everyday task of

recording, processing, filing, andmanipulation of information in the

database

Database : a collection of informationorganized in such a way that a computer

program can quickly select desired pieces

of information (or data); like an electronic

filing system

Basic features:

To add or delete information within a file

To search a file for some information based

on some criteria

To update information from within a file

To sort information into some order

To generate a printout or reports


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Graphics Software Packages

designed to allow the user to display

images on a computer monitor or to print

the images on a printer Examples of graphic applications:

paint programs

illustration/design programs

presentation graphics software

animation software

CAD software

desktop publishing


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Installation Basics

Installation Process

Copy files from distribution disks to

specified folders on the hard disk.

If the files have been distributed in acompressed format, uncompress them.

Analyze the computers resources, such as

processor speed, RAM capacity, and hard

disk capacity.

To select appropriate device drivers,

analyze hardware components andperipheral devices.

Look for any system files and players, such

as Windows Media Player or Internet

Explorer, which are required to run the

program, but not supplied on the

distribution disks.

Update necessary system files, like WindowRegistry and the Windows Program menu,

with information about the new software.


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Installation Basics

re all of the files for the software provided onthe distribution disk

Application software programs share some

common files, through the use of Windows and

other operating systems.

Because these files should already exist on

your computer, the shared files are not

typically provided on the distribution disks for

the new software program.

The installation process attempts you tolocate these files, and will notify you if any of

them are missing.


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Installing from aDistribution Disk to CD

Video Capture Software Installation Process

Insert the distribution disk, CD, or DVD.

Read the license agreement, if one is

presented on the screen.

You will be prompted to select between full

and custom installation. Choose the

installation option that best meets your needs.

Follow the instructions provided by the setup

program to specify a folder to hold the new

software program. If the software includes multiple distribution

disks, insert each one in the specified drive

when the setup program tells you to do so.

When the setup is complete, begin the

program that you just installed to make sure it

works.


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Installing DownloadedSoftware

Compressed file types for downloaded software

Manual download and install

Downloaded files with a .zip extensionmust be located on the hard disk.

Must use a program such as WinZip to

unzip it.

To acknowledge the license agreement,

the setup program must be executed.

Specify the folder for the software files,

and complete the installation.

Self-installing executable file

Follow the setup program prompts to

acknowledge the license agreement.

his self-installing executable file

automatically unzips itself and starts the

setup program.

Specify the folder for the software files,

and complete the installation.


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Installing DownloadedSoftware

Compressed file types for downloaded software

Self- executing zip file

These files automatically unzip thesoftwares files but do not automaticallystart the setup program.

To unzip the files for the new software,

the executable file must be started.

Start the setup program manually and

follow its prompts to complete theinstallation


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Uninstalling Software

You can remove software, with some

operating systems, such as DOS by simply

deleting its files.

With Windows and Mac OS, uninstall routine isprovided to delete the softwares files from

various directories on the computers hard

disk.

You can normally find the uninstall routine

with Windows software, on the same menu as

the program.

In Windows, the Add/Remove Programs icon

can be found in the Control Panel, accessible

from the Start menu.


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Software Copyrights

Copyright

a form of legal protection that grants the

author of an original work an exclusive

right to copy, distribute, sell and edit thatwork, except under special circumstances

described by copyright laws

Exceptions

The purchaser

can make a backup or extra copy of the

software in case the original copy becomeserased or damaged

is allowed to copy and distribute parts of a

software program for use in critical

reviews and teaching

has the right to copy software from a

distribution disk or Web site to a

computers hard disk in order to install it


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Software Licenses

License Agreement

a legal contract that defines the ways in

which a computer program may be used

can be found on the outside of thepackage, on a separate card inside the

package, on the CD packaging, or in one of

the program files

Techniques to validate software license

shrink-wrap licenses installation agreements


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Software Licenses

Questions to be Considered When Reading a

Software License Agreement

When does the license go into effect ? Can I sell the software ?

Can I rent the software ?

Am I buying the software or licensing it ?

Can I loan the software to a friend ?

Does the software publisher provide a

warranty ?

Under what circumstances can I make

copies ?


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Software Licenses

Public Domain Software

may be freely copied, distributed and even

resold

not protected by copyright because thecopyright has expired, or the author has

placed the program in the public domain,

making it available without restriction

Commercial Software

usually sold in computer stores or at Websites

adheres closely to the limitations provided

by copyright law

it might give you permission to install the

software on a computer at work and at

home, but you have to use only one of

them at a time


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Software Licenses

Freeware

a copyrighted software that is available for

free

does not allow you to modify it or sell it,but it allows you to use the software, copy

it and give it away

utility programs, some games and device

drivers

Shareware

a copyrighted software marketed under atry before you buy policy, allowing you

to use the software for a trial period

usually permits you to copy and distribute

it to others

provide a low-cost marketing and

distribution channel


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Software Licenses

Open Source Software

may be sold or distributed free of charge

uncompiled program instructions are

available to programmers who want toalter and improve the software

Linux, FreeBSD

Basic Computer Concept in Computer Science

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