Transcript Introduction to Computers - Jordan University of Science

COMPUTER SKILLS
CIS 100
http://www.just.edu.jo/~mqais/CIS%20100.html
1st semester 2013-2014
CH.01
INTRODUCTION TO
COMPUTERS
WHAT ARE COMPUTERS?
 Computers
are electronic devices that can follow
instructions to accept input, process the input and
then produce information. It is a machine that
manipulates data according to a set of instructions.
 Computers
are machines that perform tasks or
calculations according to a set of instructions, or
programs.

A computer is a programmable machine designed to
sequentially and automatically carry out a sequence of
arithmetic or logical operations. The particular sequence of
operations can be changed readily, allowing the computer to
solve more than one kind of problem. (Wikipedia free
encyclopedia)
‫‪HARDWARE‬‬
‫غير مطلوبة فقط للفهم‬
COMPUTERS ARE MADE OF
HARDWARE
SOFTWARE
COMPUTERS ARE MADE OF
•
Computers work through an interaction of
hardware and software.
•
Hardware refers to the parts of a computer
that you can see and touch, including the
case and everything inside it.
•
The most important piece of hardware
the central processing unit (CPU), or
microprocessor.
COMPUTERS ARE MADE OF
•
Software refers to the instructions, or
programs, that tell the hardware what to
do.
•
Ex. operating system (OS), A wordprocessing program.
HARDWARE
The parts of computer itself (tangible objects ) including :

Input devices i.e the keyboard and mouse

CPU (or Processor) and Primary memory (or
Main Memory)

Output devices

Storage devices
‫)‪Mother-Board (or Main Board‬‬
‫غير مطلوبة فقط للفهم‬
‫غير مطلوبة فقط للفهم‬
‫‪CPU‬‬
‫‪RAM‬‬
‫‪ROM‬‬
Input Devices
• Translate data from form that humans
understand to one that the computer can
work with
• Most common are keyboard and mouse
Selector Buttons

Keyboard (QWERTY keyboard, ATMs keyboard)
ATM: automatic
teller machine
EXAMPLES
OF

Mouse

Scanner
INPUT DEVICES

Optical mark recognition (Light Pin , Bar code
scanners)

Microphone

Joystick .
See Page 4 in text book
EXAMPLES OF INPUT DEVICES(2)
Point
and Draw devices
Trackball
Touchpad

Touch screen
Magnetic

stripes and smart cars.
Digital Cameras
Central Processing Unit (CPU)
• Is the portion of a computer
system that carries out the
instructions of a computer
program, and is the primary
element carrying out the functions
of the computer or other
processing device.
• The speed (clock speed) of CPU
measured by Hertz (GHz)
The CPU consists of :

Control Unit (CU)

Arithmetic and Logical Unit (ALU)

Some Registers
The Control Unit (CU) :
coordinates all activities of the
computer by:

Determining which operations to perform and in what order to
carry them out.

The CU transmits coordinating control signals to other computer
components.
The ALU :
consists of electronic circuitry to
perform:

Arithmetic operations (addition, subtraction, multiplication and
division)

Logical operations (and, or, not, …) and to make some
comparisons (less-than, equal, … etc.)
PRIMARY MEMORY

Memory (fast, expensive, short-term memory):
Enables a computer to store, at least temporarily,
data, programs, and intermediate results.

Two general parts:
RAM
2. ROM
1.
 its
a primary storage or random access memory
(RAM).
 it temporarily holds data and programs for use
during processing (volatile: information stored in
RAM is lost when the computer is turned off).
 RAM is the memory that the computer uses to
temporarily store the information as it is being
processed. The more information being processed
the more RAM the computer needs.
RAM

RAM (MAIN
consists MEMORY)
of locations or cells. Each cell has a
unique address which distinguishes it from other
cells.
Address
Memory locations
1
Memory Cell
2
3
n
MAIN MEMORY
MAIN MEMORY
ROM is part of memory

Programmed at manufacturing time

Its contents cannot be changed by users

It is a permanent store
ROM: READ ONLY MEMORY
Q: Mention some examples of ROM?
A: (PROM & EPROM )




PROM: Programmable Read Only Memory.
EPROM: Erasable Programmable Read Only
Memory
Cache Memory
Registers: not part of the main memory.
OTHER KIND OF MEMORY
Q : Registers are part of “ …… ” ?
Secondary Storage
 Stores data and programs
permanently: its retained after the
power is turned off
 Examples
• Hard Drive (Hard Disk)
Located outside the CPU, but most often
contained in the system cabinet
• Floppy Disk
• Optical Laser Discs
CD-ROM, CD-RW, and DVD
KINDS OF DISK DRIVES
Common Secondary Media
• Diskettes
– Data represented as magnetic spots on removable
flexible plastic disks
– Most common size is 3 1/2 inches, in a rigid plastic
case
– Disk drive holds the diskette, reads or retrieves
the data and writes or stores data
Common Secondary Media
• Hard drive
– Data is represented magnetically as with
diskettes
– Normally more than one rigid platter in a
sealed unit
– These disks are not removable
– Significantly more capacity and faster
operating than diskettes
Common Secondary Media
Hard drive
Common Secondary Media
 OPTICAL LASER DISCS

CD ROM & DVD’s

Data is represented as pits and lands

Some kinds are read only (CD-ROM) and some Kinds are rewritable (CDRW)

Significantly more capacity and faster operating than diskettes
DVD: Digital Video Disk
Common Secondary Media
Disk size
Amount of storage
Approximate printed
8.5 x 11 inch pages
5.25 low density
360 Kb
180 pages
3.5 low density
720 Kb
360 pages
5.25 high density
1.2 Mb
600 pages
3.5 high density
1.44 Mb
720 pages
CD
700 MB
a small library
DVD
8.5 GB
a feature length movie
Common Secondary Media

tapes

Panasonic's LS120 3.5 inch diskettes

Iomega's Zip & Jazz disks

VCR tape (Video Cassette Recorder )

Flash USB disks

MMC (Multi Media Card )

SD
CPU
Output Devices
Pieces of equipment that translate the
processed information from the CPU into a
form that humans can understand.

Monitors

Printers

Dot matrix printers

Ink jet printers

Laser printers

OUTPUT
Sound
BlastersDEVICES
(Sound Card By Creative Lab)

Controlling other devices
Software
• A collection of computer programs and
related data that provide the
instructions for telling a computer what
to do and how to do it.
TYPES OF SOFTWARE
1- System software: helps run the computer
hardware and computer system.
2- Application software: allows end users to
accomplish one or more specific (not
directly computer development related)
tasks.
3- Programming software : usually provides
tools to assist a programmer in writing
computer programs, and software using
different programming languages in a
more convenient way.
SYSTEM SOFTWARE
The most important
System Software
is the
Operating System
Examples of operating systems:
Windows XP (GUI: graphical user interface )
DOS (Command base),
Apple,
UNIX
System Software
• The software that controls everything
that happens in a computer.
• Background software, manages the
computer’s internal resources
Resources examples : CPU, RAM , I/O devices, …
All hardware and software are under the control of the operating
system.
Among other things,
the operating system:
1.
Determines how valuable RAM is allotted to programs.
2.
Performs tasks related to file management.
3.
Sets priorities for handling tasks.
4.
Manages the flow of instructions, data and information
to and from the processor (CPU).
Examples of Microcomputer
Operating System Software
• DOS - original standard for IBM
compatibles
• Windows - a graphical operating
environment
 Windows VISTA, XP, millennium,
2000, 98, and 95
Continue …
Examples of Microcomputer
Operating System Software Cont.
• Windows NT - for powerful workstations &
networks
• OS/2 - competitor to Windows 2000
• Macintosh Operating System
• Unix - originally for minicomputers, now used
on microcomputers and Internet servers
Question: List some examples of operating systems ?
Application Software
Packaged
Custom
• Packaged - “off the shelf”, pre-written
programs ( General purpose)
• Custom - written for an organization’s
specific purpose (Special purpose)
Application Software – Basic Tools
• Word processors– example: Microsoft
word
• Spreadsheets-- example: Microsoft
Excel
• Database managers-- example:
Microsoft Access
• Graphics-- example: Photoshop
Spreadsheets: Computer software that allows the user to enter
columns and rows of numbers in a accounting book like format.
Bit (Binary Digit)(takes two values: 1 or 0)
 Byte = 8 bits

KB (Kilo-byte) = 1024 bytes
 MB (mega-byte) = 1024 KB
 GB (giga-byte) = 1024 MB
UNITS OF MEASUREMENTS
 TB (Tera-byte) = 1024 GB

Remark: 1024=210
FOUR KINDS OF COMPUTERS
1.
Microcomputers
3. Mainframe computers
2. Minicomputers
4. Supercomputers
Comparison between the previous kinds of computers may
made based on :









Price
Processing Speed
Storage Capacity
Powerful
Single-user or Multi-user
Supporting hundreds (or thousands) of users simultaneously
Computer Size
Companies size
…etc.
Microcomputer
=>Personal
Computer => PC

Personal Computer (PC): A small, single-user computer based on a
microprocessor.
MICROCOMPUTERS
DESKTOP COMPUTER

Small enough for a desktop, but not easily
portable

Personal computers (PC’s) run general purpose
software and are employed by a wide spectrum of
users
PORTABLE COMPUTERS

Easily transported from one place to another
PORTABLE COMPUTERS
• Four categories
1. Laptops
2. Notebooks
3. Sub-notebooks
4. Personal Digital
Assistants (PDA)
Q: list all portable
computer categories?
PDA
MINICOMPUTERS
A
multi-user computer capable of supporting up
to hundreds of users simultaneously.
 Desk-sized
 More
processing speed and storage capacity
than microcomputers
 General data processing needs at small
companies
 Larger companies use them for specific
purposes
‫غير مطلوبة “‪“OMITTED‬‬
MAINFRAME COMPUTERS
A
powerful multi-user computer
capable of supporting many hundreds
or thousands of users
simultaneously.
 Larger machines with special wiring
and environmental controls
 Faster processing and greater storage
than minicomputers
 Typical machine in large organizations
‫غير مطلوبة “‪“OMITTED‬‬
SUPERCOMPUTERS

An extremely fast computer that can perform hundreds of millions of
instructions per second.

The most powerful of the four categories

Used by very large organizations, particularly for very math-intensive
types of tasks
SUPERCOMPUTERS
Characteristics of Computers
1- Store a large amount of data and
information for a long period of time.
2- process data and information in high
accuracy level .
3- Speed in processing data information.
4- Sharing of information / network.
Understanding the difference between Data,
Information and Knowledge:
Data
Computer
Information
Knowledge
 Data: is the name given to basic facts such as
names and numbers.
 Information: is data that has been converted
into a more useful or intelligible form.
 Knowledge: arrangement of information and
classifying information of the same type or
the same topic.
e.
g.
-2 4 0 -3 10
(data)
||
sort
\ /
-3 -2 0 4 10 (information)
Data
• Document files
• Worksheet files
• Database files
INFORMATIO
N
Information: the result of processing data.

Information:

Must serve a useful purpose

Must be of an acceptable level of accuracy

Must be available at the right time

Must be relevant to the enterprise, person, … etc.
KNOWLEDGE

Putting a number of information with the same type or same topic would be
a knowledge.
Processing data produces
information, and processing
information produces
knowledge.
COMPUTER VIRUSES
A
computer virus
are small software programs
that are designed to spread from one computer to
another and to interfere with computer operation.
A virus might corrupt or delete data on your
computer, use your e-mail program to spread itself
COMPUTER
to other
computers, orVIRUSES
even erase everything on
your hard disk.

Win32/Conficker

INF/Autorun

Win32/PSW.OnLineGames

n32/Agent
EXAMPLES OF VIRUSES
VIRUSES AND VIRUS PROTECTION

A virus program

Infects programs, documents, databases and
more …

It is man-made

It can hide and reproduce

It can lay dormant (inactive) and then activate
Anti-virus programs can help
TYPES OF COMPUTER VIRUSES
 Macro
Viruses
 Network
Viruses
•Trojan Horses
 Logic
Bombs
Companion Viruses
 Boot
Sector Viruses
Multipartite Viruses
TYPES OF COMPUTER VIRUSES

Macro Viruses
A macro virus, often scripted into common application
programs such as Word or Excel, is spread by infecting
documents.

Network Viruses
rapidly spreads through a Local Network Area (LAN), and
sometimes throughout the internet.
•Trojan Horses
The Trojan virus once on your computer, doesn't reproduce,
but instead makes your computer susceptible to malicious
intruders by allowing them to access and read your files.
Making this type of virus extremely dangerous to your
computer's security and your personal privacy.
TYPES OF COMPUTER VIRUSES

Logic Bombs
a piece of code that are inputted into a software
system. When a certain and specific condition is met,
such as clicking on an internet browser or opening a
particular file, the logic bomb virus is set off.

Companion Viruses
takes advantage of MS-DOS. This virus creates a new
file with typically the .COM extensions, but sometimes
the .EXD extension as well.
TYPES OF COMPUTER VIRUSES

Boot Sector Viruses
generally hide in the boot sector, either in the
bootable disk or the hard drive. Unlike most viruses, this
virus does not harm the files in the hard disk, but harm
the hard disk itself.

Multipartite Viruses
spreaded through infected media and usually hides in
the memory. Gradually, the virus moves to the boot
sector of the hard drive and infects executable files on
the hard drive and later across the computer system.
SOURCES OF COMPUTER
VIRUSES

Three primary sources

The Internet


Diskettes


Via downloads and exchanges
Exchanging disks
Computer networks

Can spread from one network to another

Lack of storage capability

Decrease in the speed of executing programs


HOW
DO
YOU
KNOW
Halting the system
IF YOU HAVE A VIRUS?
Unexpected error messages
VIRUS PROTECTION
• The software package distributed with new
PCs always includes an antiviral program.
The best way to cope with viruses is to
recognize their existence and use an
antiviral, or antivirus program.
Some tips that will help minimize your
vulnerability to viruses:
1.
2.
3.
4.
5.
6.
Delete e-mails from unknown or suspicious,
untrustworthy (unreliable) sources, especially those
with files attached to an e-mail.
Never open a file attached to an e-mail unless you
know what it is, even if it appears to come from a
friend.
Download files from the Internet only from legitimate
and reputable sources.
Update your antivirus software at least every two weeks
as over 200 viruses are discovered each month.
Backup your files periodically
Traditionally virus protection has been at the PC or
client level. However, this may change as companies
look to network and Internet service providers for more
services.