What is a Computer System

What is a SYSTEM ?
• A system is a combination
of components working
together.

What is a COMPUTER SYSTEM ?
• A computer system is a group of
elements performing together to
process data.
INPUT

PROCESS

OUTPUT

What is a COMPUTER ?
•A
computer
is
a
programmable
electronic
device that can store, retrieve,
and process data.

Why do we USE computers ?

• For convenience
• Can process voluminous data
efficiently
• More accurate (e.g. calculations)
• Increased productivity
• Capable of routine & dangerous
tasks
• Faster, thus saves TIME

Where are computers used?

• Business industry – financial
management
• Hospitals – document management
• Educational Institutions – student
records database management

CATEGORIES OF
COMPUTER

MAINFRAME
•
started its implementation during
•
•

1940s
were number-crunching machines that
took up whole building and cost huge
sums of money.
requires highly skilled people to operate

MINICOMPUTER
•
closet-sized
•
enabled multiple simultaneous
users
to access an expanded
range of applications and did so at a
substantially reduced size,
complexity and price compared to
mainframe computers.

MICROCOMPUTER
•
fitted on a desktop
•
can be use by one person at a
time, but could run many different
types of applications

Informatics Computer Institute

The Three Major COMPONENTS:
COMPONENTS
• HARDWARE
• SOFTWARE
• PEOPLEWARE

HARDWARE
• the tangible objects used with
programs in the computer system
• refers to the physical components
of the computer system, like chips,
disk drives, monitors, keyboards,
printers, & ports.

CLASSIFICATIONS of
HARDWARE

• PERIPHERAL DEVICES
• CENTRAL
PROCESSING
UNIT
• MASS STORAGE SYSTEM

PERIPHERAL DEVICES
• Any external device attached to the central
portion of the computer.
TYPES of PERIPHERAL DEVICES
• Input – used to put data into your computer.
(e.g. keyboard & mouse)

• Output – used to display & generate
information. (e.g. monitor & printer)
• Input/Output (I/O) – used for BOTH
entering data into & extracting data from a
computer. (e.g. touch screen)

Major Components
of
Computer System

System Unit
the box that contains the
essence
of the computer
contain the computer’s brain,
its
short and long term
memory
and the wiring
that links all the
pieces together. Peripheral devices
attach to it using special connectors,
usually on the back of the box

System Unit
– provides secure mountings for
circuit boards & storage devices
– protects delicate circuitry from the
outside
– protects you from interference &
dangerous voltage

Keyboard
- the typewriter component of a
PC. It enables you to enter
letters,
numbers, and special characters
into the computer.

Mouse
- a primary input device on a modern
computer. It enables you to
interact with images on the
monitor
screen by controlling an
on-screen
icon called a cursor.

Monitor
- the computer’s primary output
device. Over the years,
monitors
have progressed from
small, black
screens with crudely formed glowing
green
or orange
characters to
large,
flat-panel
screens that
display photographic-quality images
in over 4 billion colors.

Speakers
- provide the audio output for your
system. The first PC speaker
systems often consisted of two rather
cheap speakers,
but
today’s
computer sound systems may have
up to six
speakers,
including a
subwoofer.

Internal Components of a
Personal Computer

Central Processing Unit (CPU)
•

that part of the computer that
performs calculations and controls
the other parts of the computer.
• is an integrated circuit, contains I/O
bus driver, ALU (arithmetic logic
unit), registers, & an instruction
decoder or control unit to direct the
operation of other parts.

Central Processing Unit (CPU)


• MOTHERBOARD

– is the printed circuit board in the
computer
that
holds
the
microprocessor, expansion slots,
additional processor chips, &
wires that compose the bus.

• MEMORY

– is the internal storage area in the
computer.
- Measured in megabytes (MB) for
most PCs or gigabytes (GB) for
high-end systems.

MEMORY
• RANDOMACCESS
MEMORY (RAM)
– also considered as
the main memory
– can BOTH write and
read into it
– is volatile; thus,
dependent on
electricity to maintain
its contents.

• READ-ONLY
MEMORY (ROM)
– is the type of
memory which
permits you to read
data only.
– thus, cannot be
written to
– e.g. contains
instructions for
starting up PC


MEMORY TYPES
SDRAM

SDRAM , which is short for Synchronous
DRAM is a type of DRAM that runs in
synchronization with the memory bus.

MEMORY TYPES
DDR RAM
DDR RAM, which stands for Double Data
Rate, which is a type of SDRAM and
appeared first on the market around 2001
but didn’t catch on until about 2001 when
the mainstream motherboards started
supporting it.

• CO-PROCESSORS
– is an integrated circuit which holds
additional computer processing units
which handle specific tasks in
conjunction with the CPU.
– e.g. MATH CO-PROCESSOR,
GRAPHICS CO-PROCESSOR,
COMPRESSION CO-PROCESSOR

• EXPANSION SLOTS
– are portals that allow new signals to
enter the computer & directly read
its circuitry.
– any device that snaps into an
expansion slot is known generically
as an expansion card.
– e.g. VIDEO ADAPTERS, JOYSTICK
ADAPTERS, etc.

• BASIC INPUT/OUTPUT SYSTEM
(BIOS)
– set of programs used by the
operating system & application
programs to activate hardware.

• BASIC INPUT/OUTPUT SYSTEM
(BIOS)

• POWER SUPPLY
– aims at regulation, maintaining the
voltage as close as possible to the ideal
that’s desired by the circuits inside your
PC.

- As it operates, the power supply of your
PC attempts to make the direct current
that’s supplied to your computer as pure
as possible, as close to the ideal DC
power as produced by batteries.

• POWER SUPPLY


• PORTS
– enables the flow of information, into and out of a
computer.

MASS STORAGE SYSTEMS
• FLOPPY DISKS
– is the premier data exchange medium for
computers & most popular back up
system.
DISK
5¼”
3½”

CAPACITY
160KB, 180KB, 320KB, 360KB,
1.2MB
720KB, 1.44MB, 2.88MB

• FLOPPY DISKS


• HARD DISKS
– is the principal mass storage system in
most computers
– holds all of your programs & data/files
– no other peripheral device can approach
the usefulness of hard disks in terms of
speed, capacity, & straightforward user
installation.


• HARD DISKS


• TAPE

– magnetically coated strip of plastic
on which data can be encoded.
– similar to music cassette tapes

• OPTICAL STORAGE
– promises unique mixture of
performance, removable cartridges, &
high capacities.
Two Basic Optical-Based Storage
CD-ROM CompactSystem
Disc – Read-Only Memory
WORM

Write Once Read Many

SOFTWARE
•
•
•
•

is a computer program
pure information
may be downloaded using phone lines
may be temporarily stored in a physical medium
(e.g. diskette, hard disk, etc.)

Classification of Software:
SYSTEM SOFTWARE
APPLICATION SOFTWARE
PROGRAMMING LANGUAGES

SYSTEM SOFTWARE
• controls the application processing and
hardware resources such as memory, disk
space, & peripheral devices.
Categor
Examples
y
Operating DOS, OS/2, Windows 95 & 98,
System
Windows NT, UNIX, Novell
Norton, PC Tools, Anti-Virus, Editor,
Utilities
Disk Scanner, Debugger

APPLICATION SOFTWARE
• created to assist users with a specific task
• some of the popular applications:
–
–
–
–

perform word processing
manipulate spreadsheets
manage database
communicate with other computers


Application Software
Category

Examples

Word processor

Word, WordStar, WordPerfect, Ami-Pro

Spreadsheet

Lotus 123, Excel, Quattro

Database Mgt. System

Dbase, FoxPro, FoxBASE, Access,
Paradox

Graphics

Harvard, AutoCAD, 3D Studio, Corel

Desktop Publisher

PageMaker, Ventura, Publisher

Games

Chess master, DOOM, Basketball

Educational

MathCAD

Accounting Package

ACCPAC, DAC-Easy


PROGRAMMING
LANGUAGES
• is nothing more than a list of instructions
used to compose a step-by-step algorithm,
the computer program.
• a recipe for a microprocessor or the step-bystep instructions in a how-to manual.
• representation of the instructions in humanrecognizable form


PEOPLEWARE
Category
Technician

Examples of IT Careers
Computer Technician

Encoder

Data Encoder

Programmer

Database Programmer, System
Programmer, Application
Programmer, Game Programmer

Analyst

Programmer Analyst, System Analyst

Administrator

Database Administrator, Network
Administrator

Manager

EDP/MIS/ITS Manager, Project
manager

PC Start-up Sequence
• When you turn on your PC, it starts
itself automatically. All modern
computers can boot themselves. They
are built to run a permanently installed
programs as the very first thing when
“waking up”. That program usually is
designed to load an operating system,
but first it can do a number of useful
tests.

PC START-UP SEQUENCE
• POST (Power On Self Test)
– is the first program executed when a PC is
turned on or reset

• MS-DOS
• WINDOWS XP
–
–
–
–

Windows-based components start to load
an automatic process with Windows XP
device drivers & OS components loaded
Windows desktop is then initialized

BOOT & REBOOT
PROCEDURE
• BOOT
– the process of turning the power on for
your PC to start up.

• WARM REBOOT
Ctrl

Alt

Del

• COLD REBOOT
– turn off your PC, wait for at least 5 seconds
before turning it on again.

INTRODUCTION TO


COMPUTER NETWORK
• is an arrangement in which two or
more computers are connected so that
they can share data or peripheral
devices, or both.
• can contain a few or up to hundreds of
nodes (computer units).

Reasons to Networking
• Peripheral Sharing
– multiple users can access same printer, modem,
scanner, etc.

• File Sharing
– files can be shared among different types of
computers.

• Security
– sensitive data can be kept centrally and
accessed only by users with the proper
authority.

LAN, MAN, & WAN
• Local Area Network (LAN)
• It is a local area network is a data
communications network
spanning a limited geographical
area, a few miles at most.


A LAN is made up of the
following:
• FILE SERVER
• A powerful computer with a large
hard disk and a lot of memory. Its job
is to store the network’s programs and
data files, to handle requests for
peripheral sharing, to respond to
requests from users and to generally
mediate network traffic and
operations.

following:
• WORKSTATIONS or CLIENTS
• Computers of lesser capacity that are
depend on the file server.
• NETWORK INTERFACE CARDS
• To connect the PC to the cables.
• CABLE
• To connect the computers.

following:
• NETWORK SOFTWARE
• To connect the user and the network.
• OPERATING SYSTEM SOFTWARE
• To service user’s needs for resources
like files and printers.


LAN, MAN, & WAN
• Metropolitan Area Network (MAN)
• Once a network spans more than a
few miles or campus environment, or
such as city.
• Wide Area Network (WAN)
• Brings companies into the sphere of
networking by connecting computers
in the entire enterprise, which may
span over several cities, states and
countries.

E-MAIL & E-MAIL ADDRESS
• E-MAIL (Electronic Mail)
– is a method used to send & receive messages over a
network
– use an e-mail program to compose & send a message,
& it is sent to a remote mailbox, where it can be
retrieved and read by the addressee.
• E-MAIL ADDRESS
– is the location where email messages can be sent to a
user.
– consists of a username & an internet address,
separated by an @ sign.
– e.g. jparas@informatics.edu.ph

INTERNET
• is called the network of networks
• largest collection of interconnected
computer networks in the world
• connected through an ISP
(Internet Service Provider)

What is a Computer System

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