Elc 318 prelims handout

What is a Computer?

Computer
An electronic device which manipulates and stores data
It performs mathematical and logical operations

Parts of a Computer

System
Any collection of component elements that work together to perform a task.

E-Data Processing Hardware Software Peopleware

Computer System
A complete, working computer
The computer system includes not only the computer itself (hardware), but also any software and data that are necessary to make the computer function.
Likewise, human intervention is also needed

Components of Computer System

Hardware
Tangible parts of the computer system
It includes all the physical parts such as CPU, Monitor, keyboard and etc.

Computer Hardware

Input Devices - These are devices used to enter information into a computer

Keyboard
One of the most used input devices, consisting of keys which are pressed to enter data and instructions into the computer
IBM first introduced the 83-key keyboard followed by the 84 keys and finally 101-key keyboard which was the de facto standard, until further modifications were introduced by Microsoft.

QWERTY Keyboard Layout
Originally designed by Christopher Sholes in 1867
Its name was derived from the first six characters on the top row of normal keyboard arrangement.

Keyboard

Mouse
It is used to move on and control a pointer on the computer screen, specifically in a graphical user interface (GUI) system
This is connected to the computer by wire/ wireless and is held by hand

Trackball
It is similar to the mouse
It also has a rotating ball, but the ball is on top. Instead of moving the device itself, the user moves the ball

Joystick
This gives the computer information on the direction and extent of displacement of a hand-held lever, enabling a corresponding movement in an object on the screen that is part of particular program
Usually used for games.

Light Pen
It is shaped like a pen with the telltale cable connecting it to the computer
This is used to indicate a particular location on a a computer screen and is usually utilized for programs on computer-aided design (CAD)

Scanner
This device inputs a digital image of a document or picture into a computer.
This is usually consists of a flat bed, on which an image is placed and scanned

Graphics Tablet
This is an input device in which a stylus is moved, by hand, over a flat surface
The position of the stylus is tracked so that the user can input shapes and drawings

Touch-Sensitive Screen
This is a computer monitor, which consists of a specialized screen
Users can touch particular areas or touch-points on the screen to input certain preferences or commands

Recognition Devices
These devices are mostly used by banks and commercial establishments to recognize and input large volumes of data
These include Optical Character Recognition (OCR), Optical Mark Recognition (OMR)

Voice Recognition Device
Allow you to communicate to the computer through speech and the like
The simplest example is a condenser microphone which can be used to capture sound

Processing Device - Device used to process data into information

C entral P rocessing U nit
The main part of a computer which executes instructions and controls various other functions of the computer
It consists of Arithmetic and Logic Unit (ALU), Control Unit and the Memory

Microprocessor / CPU

System Unit
It contains the central processing unit and primary memory (the electronic circuitry that enables the computer to process and store data)

System Unit

Power Input
Where your plug in the PC’s electrical power cord

Keyboard Port
Dedicated port for the keyboard

Mouse Port
Dedicated port for the mouse

USB Ports
Universal Serial Bus ports are general-purpose connectors found on newer PCs.

Serial Ports
This-9 pin connector is one of the oldest and most universal ports found in the back of the PC.

Parallel Port
Virtually as old as the serial port, the 25-pin parallel port has been updated a number of times, popular means for connecting printers

Video Port
This unique three-row, 15-pin connector is where the monitor connects to the system unit

Audio Ports
Used to connect speakers, microphones, and other audio devices

Game Port
Also known as a joystick port, this 15-pin connector can be used for both joystick and for MIDI musical devices

Modem Port
This looks like a telephone jack.
It enables your computer to communicate with other computer via telephone line.

Network Interface
It sometimes referred to as an Ethernet connector.
It connects your PC to other PCs in a Local Area Network

Proper Opening and Shutting Down of a Computer

Opening of a Computer
Check all the cables if properly connected
Plug and switch on the AVR
Switch on the Monitor
Press the Power Button of the System Unit
Wait until the desktop appears and the cursor will look like this  before opening any program

Shutting Down of a Computer
Close all the programs
Click the Start button and click Turn Off or Shut Down
A dialog box will appear, click again the Turn Off or Shut Down button
Wait until the monitor turns off or totally black screen.
Switch Off the monitor
Switch off and unplug the AVR

Internal Components of a System Unit

CPU
Central Processing Unit
The brain of the computer
AMD (Advanced Microdevices) and Intel Corporation

Random Access Memory (RAM)
The CPU’s short-term memory.
Volatile storage
Can be accessed quickly but it disappears when the power is turned off.

Memory Devices
These are devices that are used for the temporary and short-term storage of data, which the compute can use during processing
These include ROM (Read Only Memory) and (RAM) Random Access Memory

Random Access Memory

Northbridge
A special helper chip that connects CPU and RAM
BUS – multiple wires used to connect two or more devices in the motherboard.
Frontside Bus – connects the CPU, Northbridge and RAM

CPU Speeds
Clock Chip – a crystal that oscillates at a certain frequency when electricity us applied to it, providing the system speed.
Each click of the clock is measured in millions or billions of cycles per second

Note:
One cycle per second is Hertz (Hz)
One million cycles per second is a megahertz (MHz)
One billion cycles per second is a gigahertz (GHz)

Processor Packages
The form factor of the chip : its shape, size and external features

Types of Processor Package

Single-Edge Cartridge (SEC)
Introduced in mid-1990s
Pentium II is an example of this package.

Pin-Grid Array (PGA)
Most commonly used package for the processor
It has tiny golden wires sticking out the underside of the CPU

Motherboard
The big printed circuit board that covers most of the bottom of the system unit.
Provide an area where all of the internal components of the PC can connect.

Expansion slots
Enable you to expand the capabilities of your system by adding extra components.
Any device that snaps into an expansion slot is an expansion card.

Three Types of Expansion Slots

1. PCI
Peripheral Component Interconnect
Expansion slot used for high-speed input/output device which uses PCI bus

2. AGP
Accelerated Graphics Port
Expansion slot used for a video card

3. ISA
Industry Standard Architecture
Used by older and/or slower devices

Hard Drive
The PC’s long-term memory; data stored there remains available for later use.

IDE
Integrated Drive Electronics
A standard that defines how the motherboard communicates with secondary storage devices.

CD-ROM Drives
Compact Disc – Read Only Memory
Design to read CDs.

CD-R
Compact Disc Recordable
Allow you to write data to them but only one time

CD-RW
Compact Disc ReWritable
Enables you to read and write repeatedly.

Floppy Drives
Read floppy discs
The first kind of storage used by PCs

Data Hierarchy
Bit = 1 or 0
1 Byte = 8 bits = 1 character
1024 Bytes = 1 Kilobyte
1024 KB = 1 Megabyte
1024 MB = 1 Gigabyte
1024 G = 1 Terabyte

Video Card
Also known as graphic adapter
Act as the interface between computer and monitor

Power Supply
Converts standard household A/C current into the D/C current needed by the PC

Sound Card
Provides the sound input and output for your PC.
Used for speakers and microphones

Network Interface Card (NIC)
To access a Local Area Network

Output Devices -Display or transfer information to the user after processing

Monitor
One of the most common output devices. It is the screen which shows the results of processing or the inputs of the user
Desktop or Personal Computers come with Cathode-Ray Tube(CRT) similar to those of televisions while Laptop computers come with a Liquid Crystal Display(LCD).

Monitor

Printer
This device provides hardcopy or a printout to the user
It takes text as inputted and then prints them on paper

Types of Printer
Dot Matrix – use small wires to press on ribbons and quite noisy
Inkjet Printer – similar to matrix printers but instead of using needles it sprays droplets of ink onto the paper to form images
Laser Printer – noise-free, as these employ light to draw text and images; uses electrostatic process

Plotter
It is a special output device which also causes printed output to be produced in a manner not too different from that used by regular printers

Speakers
Provide output for voice, sound or music and are a necessary of a multimedia system

Storage Media & Devices - Provide a permanent storage for data, information and programs for later use or retrieval

Hard Disk
Most common storage media which usually permanent part of the computer
This is where most programs and data are stored, especially the operating system for fast retrieval and execution by the user

Floppy Disk
This is removable storage device which has a smaller capacity compared to a hard disk
The standard 3.5-inch floppy disk has 1.44 MB capacity

Compact Disc (CD)
Also a removable device with a larger capacity than a floppy
It usually come in the form of CD-ROM (Compact Disc-Read Only Memory)
The common capacity of a CD-ROM is 650MB
There are also recordable and erasable CDs

Digital Video Disc (DVD)
CDs which contain a very large amount of data and are used for storing films and other data-intensive files such as computer games and applications
Usually store up to 8 GB of data

Hardware Connection - These are the connectors that physically connect and link the components and devices so that they can interact and exchange data

BUS
This is a group of wires composing a system interconnections that allow communication between the different devices
It is the electrical pathway through which the computer processor communicates

Circuit Boards
These are arrangements of electrical components through which signals or current can pass through

Serial Connection
This type of connection which involves a slow transfer of information from the computer to an external component such as mouse or printer

Parallel Connection
Uses multiple sets of wires but is limited in terms of distance covered
It also connects components such as printers or scanners to the computer

Types of Software

System Software
The kind of software that controls and takes care of the working computer and overall functioning of the system.
The best example of system software is the operating system
Ex. Windows XP, Windows ME, Windows XP, Linux, Unix, Apple’s OS

Application Software
Software that generally suited to perform a particular task or function
Ex. Word Processor, Spreadsheet, Computer Games, Desktop Publishing Software and Graphics Program

Types of Production of Software

Commercial Software
These are created and marketed by big software companies
Usually made by a team of experts and computer professionals and are sold for quite a big price
Ex. Microsoft Windows OS, MS Office

Shareware
Because of the high cost of software, many individual programmers made shareware
Shareware, however is not really shared but is lent or allowed to be tested for a time before a fee is requested

Freeware
Given for free or allowed to be downloaded from the Internet.
Programmers who create freeware do it as a service to users who cannot afford programs

Output Device
It displays data once it has been processed.
The most common output devices are the computer display screen and printer

Secondary Storage Device
It allows data to be permanently stored so that it can be used at a later time.
Common secondary storage devices include floppy disk drives, hard disk drives, and CD-ROM drives

Note:
Input, output and secondary storage devices are also sometimes referred to as peripheral devices

Software
It is a set of instructions that tells the computer hardware what to do.
It is also known as program
Examples: MS Word, Excel, & PowerPoint

Peopleware
They are mainly responsible for the development and use of the system
No computer would run without the help of people

How the Computer Works?

Electronic vs. Electric

Computer
It is an electronic device
An electronic device uses very small electric current at very low voltage levels to represent and store state information

Electronic Device
Generally, at 0 volt the state is off and at 5 volts the state is on.
Power dissipation for computers, particularly portable such as laptops and palmtops is kept low.

Electric Appliance
It uses raw power to operate and function and not to store or represent data
Air-conditioning units, refrigerators, electric fans, and the like all use powerline voltage levels of 110 or 220 volts.

Does it mean that computers do not require powerline electricity?

The answer is NO.
Computers use the 110- or 220-volt electricity for their power supply and internally convert this to the appropriate voltage levels.

Let us see how an on or an off is used to represent data.

Data Hierarchy

Bit
Smallest unit of data
Represented by 0 or 1

Nibble
It consists of four bits

Byte
It consists of 8 bits or 1 character
Character – smallest meaningful unit of data

Kilobyte (KB)
It consists of 1024 bytes

Megabyte (MB)
It consists of 1024 KB

Gigabyte (GB)
It consists of 1024 MB

Terabyte (TB)
It consists of 1024 GB

Petabyte (PB)
It consists of 1024 TB

Exabyte (EB)
It consists of 1024 PB

Proper Care of Computers

Here are some ways:
Place your computer in a dry, clean and cool place
Do not eat or drink while working on your computer

Here are some ways:
Clean your computer regularly. Use dry cloth and a wax specially made for computers.
Cover your computer when not in use so that dust will not gather on it.

continuation…
When you are using a computer, handle its parts with care.
Do not hit your computer when there is something wrong with it. Call somebody who is technically knowledgeable in fixing the problem.

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Run the shutdown program before turning off ,your computer. Failure to do so many results in data loss.
Clean your mouse regularly so that you will not have difficult rolling it over a mouse pad.

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Protect the data stored in your storage media. Place your disks and CD-ROM in a protective case. Don’t bend your disks or put them near magnets. Magnets will damage the data stored in your disks.

Computer Problems and Issues

Software Breakdown

Things to do when Software Breakdown occurs
Turn the computer off and then on again (cold booting), then run the program again

Things to do when Software Breakdown occurs
If the program continues to encounter difficulties, try reinstalling it.
If the problem continues, contact your software vendor or dealer and try replacing the software.

Note:
This problem may occurs due to other problems such as a hard disk loaded with too many programs, viruses or just simple incompatibility with the hardware.

Hard Disk Crash

Hard Disk Crash
One of the worst experiences for a new user
When you turn on the computer and nothing happens
You find out that all the contents of your hard disk are totally erased without recovering any file

Things to do when Hard Disk Crash occurs
Have your hard disk checked if there is hope for recovering any important data or file

Things to do when Hard Disk Crash occurs
Have your hard disk reformatted and programs you want to reinstalled
The next time you use your computer, have a BACKUP of all your important files in another storage media.

Virus Attacks

Virus Attacks
Hard disk may crash caused by viruses
Computer may behave in an unpredictable manner
The software or programs may breakdown

Let us understand what a virus IS NOT
A virus is not a germ, bacteria or organic virus
A virus is not a malfunction of any devices or computer part.

What, then is a VIRUS?
It is a program that copy itself, and then transfer from one computer to another without users knowing it.

What, then is a VIRUS?
The program cannot be seen like an ordinary file. It is hidden within executable files or data
It is made to either express something through screen, or to infect and erase data

Things to do to in Virus Attacks
Always BACKUP your important data
Install an anti-virus program on your computer.

Things to do to in Virus Attacks
NEVER share floppy disk and other storage media with other computer users. Also don’t use pirated software.
Don’t open or access unknown files or attachment in the Internet as these be affected by a virus

Safety Precautions for Working on a Computer

#1
Make notes as you work so that you can go back step-by-step to check your work later if necessary

#2
When unpacking hardware or software, remove the packing tape and cellophane from the work area as soon as possible

#3
Keep components away from your hair and clothing

#4
Keep screws and spacers orderly and in one place, such as a cup or tray

#5
Do not stack boards on top of each other, you could remove a chip accidentally.

#6
When handling motherboards and expansion cards do not touch the chips on the boards

#7
Hold expansion cards by the edges. Do not touch any soldered components on a card, and do not touch chips or edge connectors unless it is absolutely necessary. Do not touch a chip with a magnetized screwdriver.

#8
Do not use a graphite pencil to change DIP switch settings, because graphite is a conductor of electricity and the graphite can lodge in the switch.

#9
Always turn off a computer before moving it. A computer’s hard drive always spin while it is on, unless it has a sleep mode.

#10
Always turn off a computer before moving it. A computer’s hard drive always spin while it is on, unless it has a sleep mode.

#11
To protect disks, keep them away from magnetic fields, heat and extreme cold. Do not open the shuttle window or touch the disk’s surface.

#12
The power supply and the monitor can hold a dangerous level of electricity even after you turn them off and disconnect from a power source.

Protecting Against Electrostatic Discharge

ElectroStatic Discharge (ESD)
Commonly known as static electricity
An electrical charge that can build up on the surface of insulating materials, such as clothing or plastic.
This is why touching a metal doorknob after you cross a carpet in your stocking feet can result in a very noticeable shock.

Why worry about ESD?
A charge of much less than 3000 volts can damage electronic components .
Walking across carpet can generate 1,500 to 30,000 volts of static electricity.
Just picking up a common plastic bag can generate over 1,000 volts and often much more.

How to prevent ESD?
Ground Bracelet or Antistatic Wrist Strap
Ground Mat
Static Shielding Bag

Manual Way to prevent ESD
As you work on a computer, make a point of touching the metal frame or power supply box before you touch any other part.
Touch it again every time you move around, this will at least equalize the amount of static electricity stored up and waiting to move in you and in the PC.

Lab Activities

Handling PC Connections
Identify the types of ports and connections
You need a computer with standard peripherals attached including a mouse, keyboard and monitor.

Opening a System Unit
You need:
PC
A Phillips screwdriver
Preferably an antistatic wrist strap
Identify the internal parts of the System Unit

Handling Expansion Cards
You need:
A PC running Windows
A Phillips screwdriver
A straight-slot screwdriver
An Antistatic wrist strap
A three-prong parts retriever

Identifying the Type of CPU in Your PC
A working PC running Windows
Paper and Pencil
Screwdrivers
An antistatic wrist strap
You need to know the manufacturer, model, speed and package.

Five ways to identify the type of the CPU
System Information
My Computer Properties
Physical Connection
Reboot
CPU-Z (Application Program) can be downloaded at www.cpuid.com

Elc 318 prelims handout

by Jeph Pedrigal

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Elc 318 prelims handout Presentation Transcript