HEALTH INFO (WEEK 2) : INTRODUCTION TO COMPUTERS

COMPUTER

An electronic device, operating under the control of instructions stored in its own memory that can accept data (input), process the data according to specified rules, produce information (output), and store the information for future use

FUNCTIONALITIES OF A COMPUTER

● Take data as input

● Stores the data/instructions in its memory and use them when required

● Processes the data and converts it into useful information

● Generates the output

● Controls all the above four steps

PARTS OF THE COMPUTER SYSTEM

Hardware

Software

Data

User

HARDWARE

● The computer equipment

● Computer hardware is the collection of physical elements “tangible objects” that constitutes a computer system

● The actual machinery, wires, transistors, and circuit

● Mechanical devices in the computer

● Anything that can be touched

● Includes printers, monitors disk drives, etc.

SOFTWARE

● Programs which tell the computer what to do

● Instructions and data

● Also called a program

● Thousands of programs exist

DATA

● Pieces of information

● Computer organize and present data

USER

● People operating the computer

● Most important part

● Tell the computer what to do

INFORMATION PROCESSING CYCLE (Steps followed to process data:)

1. Input Unit

2. Central Processing Unit

3. Primary Memory Unit

4. Secondary Storage Unit

5. Output Unit

INPUT DEVICES

● Any peripheral (piece of computer hardware equipment to provide data and control signals to an information processing system such as a computer or other information appliance

● Translate data from a form that humans understand to one that the computer can work with.

● Most common are keyboard and mouse

MOST COMMONLY USED KEYBOARD? HOW MANY KEYS?

Qwerty Keyboard / 104 keys

CENTRAL PROCESSING UNIT (CPU)

● Known as microprocessor or processor

● It is responsible for all functions and processes

THREE MAIN PARTS OF THE CPU:

• ALU (Arithmetic Logic Unit

• Control Unit (CU)

  • Registers

ALU (Arithmetic Logic Unit)

● Executes all arithmetic and logical operations

● Arithmetic calculations like as addition, subtraction, multiplication, and division

● Logical operations like compare numbers, letters, or special characters

CONTROL UNIT (CU)

● Controls and coordinates computer components

● Read the code for the next instruction to be executed

● Increment the program counter so it points to the net instructions

● Read whatever data the instruction requires from cells in memory

● Provide the necessary data to an ALU or register

● If the instruction requires and ALU or specialized hardware to complete, instruct the hardware perform the requested operation

REGISTERS

Store the data that is to be executed next, “very fast storage area”

ROM

RAM

TWO TYPES OF PRIMARY MEMORY

RAM (RANDOM ACCESS MEMORY)

• a memory scheme within the computer system responsible for storing data on a temporary basis, so that it can be promptly accessed by the processor as and when needed.

• considered "random access" because you can access any memory cell directly if you know the row and column that intersect at that cell

ROM(READ ONLY MEMORY)

● a permanent form of storage.

● stays active regardless of whether power supply to it is turned on or off.

● devices do not allow data stored on them to be modified

1. Hard Disk

2. Optical Disk

3. Flash Memory

MAIN EXAMPLES OF THE SECONDARY MEMORY

SECONDARY MEMORY

Stores data and programs permanently

HARD DISK

● Called a "disk drive," "hard drive," or "hard disk drive” (HDD) ● Store and provides relatively quick access to large amounts of data

● Stores data on an electromagnetically charged surface or set of surfaces

OPTICAL DISK

An optical disk drive (ODD) is a disk drive that uses laser light to store data

• CD (Compact Disk)

• DVD (Digital Video Disk)

• Blu-ray Disc

THREE TYPES OF OPTICAL MEDIA:

CD (COMPACT DISC)

cans store up to 700 MB

DVD (DIGITAL VIDEO DISK)

can store up to 8.4 GB

BLU-RAY DISC

can store up to 50 GB

FLASH MEMORY

● A storage module made of flash memory chips.

● Flash disks have no mechanical platters or access arms, but the term "disk" is used because the data are accessed as if they were on a hard drive.

● The disk storage structure is emulated.

OUTPUT UNIT

● An output device is any piece of computer hardware equipment used to communicate the results of data processing carried out by an information processing system (such as a computer)

● Converts the electronically generated information into human-readable form

SOFTWARE

Software is a generic term for organized collections of computer data and instructions

1. System Software

2. Application Software

TWO MAJOR CATEGORIES OF SOFTWARE:

SYSTEM SOFTWARE

● Known as Operating System

● Is responsible for controlling, integrating, and managing the individual hardware components of a computer system

APPICATION SOFTWARE

is used to accomplish specific tasks other than just running the computer system

COMPUTERS CAN BE CLASSIFIED BY SIZE AND POWER TO:

1. Personal Computers

2. Workstation

3. Minicomputer

4. Mainframe

5. Super Computer

PERSONAL COMPUTER

A small, single user computer based on a microprocessor. In addition to the microprocessor, a personal computer has a keyboard for entering data, a monitor for displaying information, and a storage device for saving data.

WORKSTATION

A powerful, single-user computer. A workstation is like a personal computer, but it has a more powerful microprocessor and a higher-quality monitor.

MINI COMPUTER

Multi-user computer capable of supporting from 10 to hundreds of users simultaneously.

MAINFRAME

Powerful multi-user computer capable of supporting many hundreds or thousands of users simultaneously

SUPERCOMPUTER

An extremely fast computer that can perform hundreds of millions of instructions per second.

● Price

● Processing Speed

● Storage Capacity

● Powerful

● Single-user or Multi-user

● Computer Size

● Companies Size

COMPARE BETWEEN THE PREVIOUS TYPE OF COMPUTER BASED ON

• Laptop Computer

• Netbook Computer

• Mobiles Devices

• Tablet Computers

• Smartphones

TYPES OF DIFFERENT DEVICES/COMPUTER:

1. Speed

2. Reliability & Consistency

3. Accuracy

4. Storage

5. Communications

WHY IS A COMPUTER SO POWERFUL?

1. Speed

2. Accuracy

3. Diligence

4. Storage Capacity

5. Versatility

CHARACTERISTICS OF COMPUTER:

• Viruses

• Email viruses

• Trojan Horses

• Worms

COMPUTER VIRUSES

VIRUSES

• A computer virus is an application program designed and written to destroy other programs.

• A virus is a small piece of software that piggybacks on real programs

EMAIL VIRUSES

• E-mail virus travels as an attachment to e-mail messages

• Replicates itself by automatically mailing itself to dozens of people in the victim’s email address book

TROJAN HORSES

• Simply a computer program

• The program claims to do one thing (it may claim to be a game) but instead does damage when you run it

WORMS

a small piece of software that uses computer networks and security holes to replicate itself

1. Lack of storage capability

2. Decrease in the speed of executing programs

3. Unexpected error messages

4. Halting the system

MALICIOUS SOFTWARE (How do you know if you have a virus)