Understanding Computers - Introduction to Computers

What is a computer?
A computer is a programmable, electronic device
that accepts data, performs operations on that
data, presents the results, and stores the data or
results as needed

What does a computer do?
A computer can perform four general operations:
Input (entering data into a computer)
Processing (performing operations on the data)
Output (presenting the results)
Storage (saving data, programs, or output)

Data vs. Information
Data: almost any kind of fact or set of facts
Information Processing: the conversion of data into
information
Information: processed data into a meaningful form
Data
• Raw,
unorganized,
unprocessed
facts
Information
Processing
Information
• Data that has
been processed
into a
meaningful form

What is hardware?
Hardware is the
physical part of
a computer, that
you can touch
Examples:
 Keyboard
 Mouse
 Monitor
 Printer
 Scanner
 speaker

What is software?
Software refers to the programs or instructions
used to tell the computer hardware what to do

Types of software: 1. System Software
 The programs that
allow a computer
to operate are
collectively
referred to as
system software.
 Examples:
 Windows, Mac
 LINUX, UNIX
 Android, Symbian

Types of software: 2. Application Software
 Application software
consists of programs
designed to allow
people to perform
specific task
 Examples:
 Microsoft Office
(Word, Excel,
PowerPoint, Access)
 Adobe Photoshop,
Acrobat
 Internet explorer

Types of Users
 Computer Users (End Users) -- People who use
computers to perform tasks or obtain information
 Programmers – Computer Professionals who write, test,
and maintain computer programs
 System Analysts – Computer Professionals who analyze
and design computer systems to solve business problems
 Operations Personnel – Computer Professionals who are
responsible for the day-to-day computer operations

Types of computers: 1. Embedded Computers
 A tiny computer
embedded into a
product and
designed to perform
specific tasks or
functions
 Examples:
 Washing machine
 Microwave
 Televisions
 Cars

Types of computers: 2. Mobile Devices
 A very small
communication device
with built-in
computing or internet
capability
 Examples:
 Smart phones
 Smart watches
 Handheld gaming devices
 Portable digital media
players

Types of computers: 3. Personal Computers
 A computer
designed to be used
by one person at a
time
Examples:
 Desktop Computers
 Portable Computers
(Notebook/Laptop,
Tablet, Netbook,
Ultra-mobile
PC/Handheld
Computer)

Types of computers: 4. Midrange
Server/Computer
 A medium-sized
computer used to
host programs and
data for a small
network
Example:
 Medical or dental
offices
 School computer lab
 Home & small
business servers

Types of computers: 5. Mainframe Computer
 A powerful
computer used by
many large
organizations to
manage large
amounts of
centralized data and
programs
Examples:
 Hospitals
 Universities
 Banks
 Government offices

Types of computers: 6. Supercomputer
 The most
powerful and
most expensive
computer for
complex
computations and
processing
Examples:
 Space Missions
and Satellite
Controls
 Weather
forecasting
 Oil exploration
 Scientific research

Basic types of data
 Multimedia
 Integration of multiple forms of media
 Computer information represented through audio, video,
animation, in addition to, text, image
Data
Text Number Image Audio Video

Digital data representation
 Bit (Binary digit) -- the
smallest unit of data
that can be stored in a
computer (0 or 1)
 Byte -- a group of 8 bits
 Bit Pattern -- a string of
bits, example,
10011101110110001
Data Unit Conversion
1 KB (Kilobyte) ≈ 1 thousand bytes
1 MB (Megabyte) ≈ 1 million bytes
1 GB (Gigabyte) ≈ 1 billion bytes
1 TB (Terabyte) ≈ 1 trillion bytes
1 PB (Petabyte) ≈ 1000 terabytes
1 0 1 0 1 1 0 0
Byte
Bit

Coding Standards for Text-based Data (Characters)
 ASCII (American Standard Code for Information Interchange)
 uses 7-bit code to represent each character
 Each 7-bit code can represent up to 128 characters
(27 unique combinations)
 Extended ASCII
 EBCDIC (Extended Binary Coded Decimal Information Code)
 Unicode
 Universal international coding standard to represent
text-based data in any language
 uses (8-bit to 32-bit) code to represent each
character
 ISO (International Organization for Standardization)

Types of images: 1. Bitmap Graphic
 made of a grid or matrix of small dots (pixels; picture
elements)
 The color at each pixel is represented by binary
code/number
0 00 0 0 0 0 0
0 0
0 00 0 0 0 0 0
0 11 1 1 1 1 0
0 011 1 1 1 1
11 1 1 1 1
For monochrome (Black
& White) graphic image

Types of images: 2. Vector Graphic
 made of lines, curves and shapes
 based on vectors (paths) that lead through locations
(control points or nodes)
 all lines, curves, or shapes are represented by mathematical
formulas

Audio
The procedure to convert analog sound to digital sound
1) analog signal is sampled
2) samples are quantized
3) The quantized values are coded into binary patterns

Video
 A collection of frames (images) that are projected in sequence
dynamically
 Each image data is converted to a set of bit patterns and stored

Numerical data representation
 Decimal number system – based on 10 symbols (0, 1, 2, 3, 4, 5, 6, 7, 8, 9)
 Binary number system – based 2 symbols (0, 1)
 Octal number system – based on 8 symbols (0, 1, 2, 3, 4, 5, 6, 7)
Each octal number is represented in binary form as 3-bit pattern
 Hexadecimal number -- based on 16 symbols (0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B,
C, D, E, F)
Each hexadecimal number is represented in binary form as 4-bit pattern
0 1 2 3 4 5 6 7
000 001 010 011 100 101 110 111
0 1 2 3 4 5 6 7 8 9 A B C D E F
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111

Conversion: Decimal to Binary
Decimal (25)10 = binary (11001)2
2512631
101 1 0
Procedure: Divide the decimal number by 2 and write down remainders successively

Conversion: Decimal to Binary
Decimal (35)10 = binary (100011)2
35178421
1101 0 0
Procedure: Divide the decimal number by 2 and write down remainders successively

Conversion: Binary to Decimal
Binary (11001)2 = Decimal (25)10
16 8 0 0 1 25
16 8 4 2 1
1 1 0 0 1
Procedure: Multiply the binary number by multiple of 2 respectively and add all

Conversion: Binary to Decimal
Binary (100011)2 = Decimal (35)10
32 0 0 0 2 1 35
32 16 8 4 2 1
1 0 0 0 1 1
Procedure: Multiply the binary number by multiple of 2 respectively and add all

Motherboard– main electronic circuit board inside system unit that
contains computer chips and other connected components
Central Processing Unit (CPU)/Processor– chip located on
motherboard of computer that performs processing for the computer
o Multi-core CPU– CPU that contains processing components or core
of more than one processor in a single CPU
o Dual-core CPU– CPU that contains two separate processing cores
o Quad-core CPU– CPU that contains four separate processing cores

Bus– electronic path
on motherboard along
which data is transferred
Example:
Memory bus, Front-side
bus, PCI and PCI Express
bus, USB bus,
FireWire/IEEE 1394 bus

Port– the exterior
of the computer to which
A device may be attached
using a
connector
Example:
Monitor port, Network
port,
Modem port, USB port,
FireWire(IEEE 1394)
port,
Keyboard port, SCSI
(Small Computer
System Interface) port,
MIDI port, Audio port, etc.

Volatile memory (Primary Storage)
Memory refers to chip-based storage
RAM (Random Access Memory) – This main-memory integrated-
chip of computer provides temporary location to hold data and
programs. Generally, it is volatile (the memory content is erased
when the computer is powered down), except nonvolatile-RAM
SRAM (Static Random Access Memory) – This volatile memory
is faster but expensive. It uses electronic flip – flop gates (a
gate with two states: 0 and 1) to hold data. It doesn’t need
memory refreshing.
DRAM (Dynamic Random Access Memory)– This volatile
memory is slower but inexpensive. It uses electronic capacitors
(charged or discharged states as 1 or 0) to hold data. It needs
constant memory refreshing.
Cache Memory– group of fast memory circuitry located on or near
CPU to help speed up processing
Register– high-speed memory built into CPU that temporarily
stores data during processing

ROM (Read Only Memory) --
nonvolatile memory chip that
permanently stores data or
programs in general.
PROM (Programmable
Read Only Memory) –
nonvolatile memory
chip that can be
programmed/written
only once (one-time).
EPROM (Erasable
Programmable Read Only
Memory) – nonvolatile
memory chip that can be
erased and
reprogrammed/rewritten
many times.
Non-volatile memory

Storage systems
Floppy Disk -- low-capacity, removable disk made of flexible
plastic
Hard Drive – are used
to store programs and
data
Magnetic Hard
Drive/Disk –
contains metal
hard disks that
are tracked with
magnetic spots
representing 0s
and 1s
Solid State Drive
(SSD) – uses flash
memory technology
to store data and
programs
Hybrid Hard drive – a
combination of
magnetic hard drive
and solid-state drive
(contains flash
memory together with
magnetic hard disks)

Optical Disc – thin circular
disc that stores and reads data
using laser beam (optically)
CD (Compact Disc) – low capacity
(typically 650 MB) optical disc that
uses infrared laser for data
storage
DVD (Digital Versatile Disc) –
medium capacity (typical 4.7 GB to
8.5 GB) optical disc that uses red
laser for data storage
BD (Blue-ray Disc) – high-capacity
(typically 25 GB to 50 GB) disc
that uses blue-violet laser for data
storage

CD-ROM, DVD-ROM, and BD-ROM
discs
These discs are read-only optical
discs that come prerecorded and
user can not write
CD-R, DVD-R, DVD+R, and BD-R
discs
These discs are recordable optical
discs (write-once discs) but can
not be erased afterward
CD-RW, DVD-RW, DVD+RW, and
BD-RE discs
These discs are rewritable optical
discs that can be written to,
erased, and overwritten many
times

Flash Memory
-- a chip-based storage medium that
stores data using electrons
(electrical charge trapped or not,
i.e., 0 or 1) within flash memory cell
 Flash Memory Cards – small,
rectangular flash memory medium
containing chips, such as a
Compact Flash (CF) or Secure
Digital (SD) card
 USB Flash Drive (Universal Serial
Bus Drive) -- small storage
device that plugs into USB port
and contains flash memory media

Input Devices
Keyboard -- input device containing
numerous keys that can be used to input
letters, numbers, and other symbols
Mouse -- common pointing device that user
slides along a flat surface to move pointer
Electronic pen -- input device that is used
to write electronically on the display screen
Scanner -- input device that reads printed
text and graphics and transfers them to a
computer in digital form
Examples: Flatbed Scanner, Handheld
Scanner, Integrated Scanner
Touch Screen– display device that is
touched with finger to issue commands

Readers – input devices that read different types of
codes and marks as well as individual’s biometric
characteristics
1. Barcode Reader-- an input device that reads barcode
(optical code)
5. RFID(Radio Frequency Identification) Reader—
device used to read RFID tags (tiny chip with radio
antenna to be identified using RFID technology)
2. OMR(Optical Mark Readers)– an input device to
input data from special forms to score or tally exams,
questionnaires, ballots, etc.)
3. OCR(Optical Character Recognition) Reader– used
to recognize scanned text characters (from monthly
bills for credit cards or utilities companies, etc.) and
convert into electronic form as text
4. MICR(Magnetic Ink Character Recognition) Reader–
used to read and add magnetic-inked MICR characters
primarily during bank check/cheque processing
6. Biometric Reader— device used to input biometric
data, such as fingerprint, voice, face

Output Devices
 Display device— an output
device that contains a viewing
screen
 Monitor-- display device
for desktop computer
 Display Screen– display
device built into a
notebook computer,
netbook, UMPC etc.
 Flat-panel display– slim
type of display device that
uses electronically charged
chemicals or gases

Display Device Characteristics
Color vs. Monochrome Display Devices– display devices form images by lighting up the proper
configurations of pixels (the dots or the smallest colorable areas on a display device); picture
elements
Color Display Device-- each pixel can display a
combination of three colors (red, green, and
blue)
Monochrome Display Device-- Each pixel can only
be one of two colors (Black or White)
CRT Monitors vs. Flat-Panel Displays
CRT Monitor Display -- uses cathode-ray tube
technology (electron gun projects an electron
beam at a screen coated with red, green, and
blue phosphor dots)
Flat-Panel Display-- uses electronically charged
chemicals or gases filled in between thin panes of
glass or other transparent material

Audio Output
-- includes voice, music, and other audible sounds
Types of audio output devices:
-- Computer Speaker-- output device connected
to computers that provide audio output
-- Headphone– personal audio output device used
by an individual to hear sound
-- Headset– headphone with a built-in microphone
Flat-Panel Display Technologies
-- Liquid Crystal Display (LCD) – uses charged
liquid crystals located between two sheets of
glass or plastic
-- Organic Light Emitting Diode (OLED) Display–
uses emissive organic material to display brighter
and sharper images
-- Plasma Display– uses layered technology (a
layer of gas between two plates of glass) to
display images
-- Data Projector– display device that projects all
computer output to a wall or projection screen

Printer– output device that produces output on paper
Printer Characteristics– technology used, size, speed, print quality, etc.
Printing Technology– Printers produce images through either impact or
nonimpact technologies
Impact Printer– have a print
mechanism that actually strikes
the paper to transfer ink to the
paper
Example: dot-matrix printer
Nonimpact Printer– have a print
mechanism that does not strike/touch
the paper to transfer ink to paper
Example: Laser printer, ink-jet printer
Color vs. Black & White Printers
─ Color printer uses black, blue,
red, yellow ink to print a
document
─ often used in homes
─ expensive and slow speed
─ Black & White printer uses
black ink to print a document
─ Mostly used in business or
office places
─ Less expensive and faster speed

Personal vs. Network Printers
o Personal printer is
designed to connect
directly to a
computer
o can not be shared
o Network printer is
designed to connect
directly to a home
or office network
o can be shared over
a network
Print Resolution (dpi)– the number of dots (of
liquid ink or toner powder flecks) per inch
Print Speed (ppm)– measured in pages per
minute

Laser printer– output device that uses
laser beam (to charge drum locations) and
toner powder to print on paper
Ink-jet Printer– output device that sprays
droplets of ink to produce images on paper
Photo Printer– output device designed for
printing digital photographs
Barcode Printer– output device that print
custom barcodes on price tags, shipping
labels etc.
Portable Printer– small lightweight printer
designed to be used while on the go
Plotter/Wide-Format Printer– used to print
large documents, such as charts, drawings,
maps, blueprints, posters, banners etc.
3D Printer– output device designed to print
three-dimensional objects, such as product
prototypes etc.

Algorithm-- a step by step procedure for solving a problem
Flowchart– diagram that
represents steps of an algorithm,
workflow or process sequentially
Example: adding two numbers; A,
B
Pseudo Code– informal
description of an algorithm
in plain English
Example: adding two
numbers; X, Y
Begin
input X
input Y
Sum = X + Y
print Sum
End

Computer
Languages
Machine
Language--
binary-based
language for
representing
computer
programs that
the computer
can execute
directly
Assembly Language– a low-
level programming language
in which each statement
produces exactly one
machine instruction
Assembler-- a program for
converting Assembly
language code into Machine
code
High-level Language– more
understandable and portable
language in which each
statement accomplish
substantial tasks
Compiler– a program for
converting High-level
language code into low-level
code or binary form

What is computer network?
collection of computers and other hardware devices
that are connected together to share hardware,
software, and data, as well as to communicate
electronically with one another

Internet
Internet benefits
 Web Browsing
 E-mail
 Chatting and Entertainment
 Communication & business
 Information sharing
 the largest computer network in the world

Types of networks: 1. Local Area Network
 A network that connects devices located in a
small geographical area, such as within a
building

Types of networks: 2. Metropolitan Area
Network
 A network designed to service a metropolitan area

Types of networks: 3. Wide Area
Network (WAN)
 A network that connects devices located in a large
geographical area

Operating System
 The main component of system software that
enables the computer to manage its activities and
the resources under its control, run application
programs, and interface with the user

Function/Benefits of operating system
 Interfacing with Users
 Booting the Computer
 Configuring Devices
 Managing and Monitoring Resources and Jobs
 File Management
 Security

Differences among Operating Systems
Graphical User Interface vs. Command Line
Graphical user interface
(GUI)– graphics-based
interface that allows a user to
communicate instructions to
the computer easily
Command line interface-- user
interface that requires the
user to communicate
instructions to the computer
via typed commands

Differences among Operating Systems
Types of Operating Systems
Personal operating system-- a
type of operating system
designed to be installed on a
single personal computer
Server operating system-- a
type of operating system
designed to be installed on a
network server

Understanding Computers - Introduction to Computers

Understanding Computers - Introduction to Computers

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Understanding Computers - Introduction to Computers