ES 1

• What is Computer?

  ● A programmable machine

  ● A machine that accepts input (raw

  data), processes that input, and

  produces output (information).
• What is a Network?

  ● Two or more computers connected

  together using communications

  equipment.
• Cyberspace

  ▪ encompasses the whole wired and wireless world of

  communications.

  ▪ Term created by William Gibson – author
• Internet

  ▪ A global network of networks (tangible)

  ▪ www
• World Wide Web

  ▪ Most common use of the Internet

  ▪ Encompasses information that can be viewed through a

  web browser (web pages).
• The “All-Purpose Machine” : The Varieties of

  Computers

  1. Supercomputers

  2. Mainframes

  3. Workstations

  4. Microcomputers

  5. Microcontrollers
• Supercomputers

  ● Fastest computer

  ● Consists of thousands of

  processors and can carry out

  several trillion calculations per

  second.

  ● Used for computer simulations

  ○ tracking hurricanes,

  biological contamination, or

  understanding ocean

  currents.

  ● Processing power is the main

  difference between

  supercomputers and general-

  purpose computer systems
• Mainframes

  ● Mainframes are data

  servers designed to

  process up to 1 trillion

  web transactions daily

  with the highest levels of

  security and reliability.

  ● Used in large

  organizations – banks,

  airlines, insurance

  companies, colleges.
• Workstations

  ● workstation, a high-performance

  computer system that is basically

  designed for a single user and has

  advanced graphics capabilities, large

  storage capacity, and a powerful central

  processing unit.

  ● A workstation is more capable than a

  personal computer (PC) but is less

  advanced than a server (which can

  manage a large network of peripheral PCs

  or workstations and handle immense

  data-processing and reporting tasks).

  ● usually used for complex scientific,

  mathematical, and engineering

  calculations and for computer-aided

  design
• Microcomputer

  ● Personal Computer (PC)

  ○ Tower PC

  ○ Desktop PC

  ○ Laptop / Notebook

  ○ Personal digital assistants

  (PDAs), also called handheld

  computers or palmtops

  ● Mac

  ○ While a Mac is a PC, most

  people relate the term, PC,

  with systems that run the

  Windows operating system.
• Microcontrollers

  ● tiny, specialized

  microprocessors

  installed in “smart”

  appliances and

  automobiles

  ● also called

  embedded

  computers
• How Computers Work

  ● The purpose of a computer is to process data into

  information.
• Data (Input)

  ○ The raw facts and figures that are processed into

  information
• Information (Output)

  ○ Data that has been summarized or otherwise

  manipulated for use in decision making
• Hardware

  ○ All the machinery and equipment in a computer

  system

  ○ Tangible
• Software

  ○ All the instructions that tell the computer how to

  perform a task

  ○ Intangible
• All computers follow the same

  five basic operations

  1. Input

  2. Processing

  3. Storage

  4. Output

  5. Communications
• Input - whatever is put into (“input”) a computer system.

  Input hardware - devices that allow people to put data into the computer in a form that the computer can use.

  Mouse - an input device that is used to manipulate objects viewed on the computer display screen.

  Keyboard - an input device that converts letters, numbers, and other characters into electrical signals readable

  by the processor.
• Processing

  • Manipulating data into information

  ● Case or system cabinet

  ○ the box that houses

  ■ the processor chip

  (CPU – Central Processing Unit)

  ■ memory chips (RAM)

  ■ motherboard with power supply

  ■ secondary storage devices

  ■ video card

  ■ etc. .....
• Motherboard

  ● Motherboard - the main

  circuit board in the computer.

  ● Everything else attaches to

  the motherboard through

  connections called ports.

  ● Expansion slots - “plugs” on

  the motherboard for

  expanding the PC’s

  capabilities via additional

  circuit boards.
• Processing

  ● Processor chip

  ● A tiny piece of silicon that contains millions of

  miniature electronic circuits.
• Storage

  ● Primary Storage

  ○ Computer circuitry that temporarily holds data

  waiting to be processed and after it has been

  processed

  ○ Also called:

  ■ Memory or primary memory

  ■ RAM – Random Access Memory

  ■ Temporary storage
• Secondary Storage

  ○ The area in the computer where data

  or information is held permanently

  ○ Also simply called:

  ■ Storage
• Storage capacity is measured in:

  ● 1 byte - 1 character is represented using 1

  byte.

  = 8 bits (a bit is a 0 or a 1)

  ● 1 kilobyte - 1,024 characters.

  = 210 bytes (approx. 103 bytes)

  ● 1 megabyte - 1,048,576 characters.

  = 220 bytes (approx. 106 bytes)

  ● 1 gigabyte - more than 1 billion characters.

  = 230 bytes (approx. 109 bytes)

  ● 1 terabyte - more than 1 trillion characters.

  = 240 bytes (approx. 1012 bytes)
• Hard-disk drive - a storage device that stores billions of characters of data on a Hard-disk drive

  nonremovable disk platter.
• CD (Compact Disk) drive or DVD (Digital Video Disk) drive CD drive - a storage

  device that uses laser technology to read data from optical disks.
• Speakers - Speakers - the devices that play sounds transmitted as

  electrical signals from the sound card.
• Sound card Sound card - enhances the computer’s sound-generating capabilities by

  allowing sound to be output through speakers.
• Monitor - the display device that takes the electrical signals

  from the video card and forms an image using

  points of colored light on the screen.
• A video card controls the video

  display of your monitor
• Printer - Printer - an output device that produces text and

  graphics on paper.
• Modem - a device that sends and receives data over telephone lines to and

  from computers.
• System software

  ● Helps the computer

  perform essential

  operating tasks and

  enables the

  application software

  to run
• Application Software

  ● Enables you to perform

  specific tasks--solve

  problems, perform

  work, or entertain

  yourself
• a set of instructions given to the computer to solve a problem is called software

  
• software is a single/collection of programs that performs a particular task, software is also called program
• types of software

  
• Three Directions of Communications Development

  1. Connectivity-the ability to connect computers to one

  another by communications line, so as to provide

  online information

  2. Interactivity-two-way communication in which a user

  can respond to information he or she receives and

  modify the process

  3. Multimedia-technology that presents information in

  more than one medium--such as text, pictures, video,

  sound, and animation--in a single integrated

  communication.
• When Computers & Communications Combine:

  Convergence, Portability, & Personalization

  ● Convergence

  ○ the combining of several industries through various devices

  that exchange data in the format used by computers.

  ● Portability

  ○ the ability to be easily carried or moved.

  ● Personalization

  ○ the creation of information tailored to your preferences, such as

  stock portfolio information kept on Yahoo.com’s Web site
• ALGORITHMS

  A typical programming task can be divided into

  two phases:

  1. Problem solving phase

  ○ produce an ordered sequence of steps that

  describe solution of problem

  ○ this sequence of steps is called an algorithm

  2. Implementation phase

  ○ implement the program in some programming

  language