1. Understanding Essential Computer Concepts
Computer Applications 1

2. Definition of a computer
A computer is an electronic machine that receives, processes, stores and delivers information.
Computers are classified by:
Size
Speed
Capabilities

3. Types of Computers Types of computers include (but are not limited to)
Personal computers
Desktop
Laptop (notebooks)
Tablet PC
Hand-held
PDA’s (personal digital assistants)
MP3 players
Cell phones
Mainframe computers
Supercomputers

4. Computer System Components
Computer systems include hardware and software
Architecture or configuration is the design and construction of a computer
Specifications are the technical details about each hardware component
Data refers to information (words, numbers, graphics, etc.)
Processing is modifying data

5. Computer Systems Components (continued)
Motherboard is where processing tasks occur
Main electronic component
Is a circuit board
Microprocessor (CPU)
Transistors and electronic circuits on a silicon chip
Mounted on the motherboard
Responsible for executing instructions to process information

6. Microprocessor Speeds
Microprocessor speeds depend on:
Speed of the microprocessor (clock speed, word size and cache size)
Whether single or dual core
Clock speed is measured in megahertz (MHz), millions of cycles per second or gigahertz (GHz), billions of cycles per second
Word size refers to the amount of data that is processed at one time
Single core processor has one processor on a single chip
Dual-core processor has two processors on a single chip and can process information twice as fast

7. Computer System Components (continued)
Cards are removable circuit boards to expand the capabilities of the motherboard
Input is the data or instructions you put into the computer
Output is the results of the computer processing
Peripheral devices such as mouse, keyboards printers and storage devices accomplish input, output and storage functions
Commands are input instructions

8. Examining Input Devices
Keyboard
Can be ergonomic
Mouse
Pointing device
Rolling ball or optical
Clicking commands
Scroll wheel
Touchpad
Pointing stick
Scanner
Microphones

9. Examining Output Devices
The Monitor displays the output from a computer
Flat panel monitor uses LCD (liquid crystal display)
CRT (cathode ray tube) monitor uses gun-like devices that direct beams of electrons toward the screen to activate dots of color
A graphics display divides the screen into a matrix of small dots called pixels
Resolution is the number of pixels the monitor displays. Standard resolutions range from 640 x 480 to 1600 x 1200.
Dot pitch (dp) measures the distance between pixels. (.28 or .26 dp is typical)

10. Output Devices (continued)
To display graphics, a computer must have a graphics card, also called a video display adapter or video card.
Speakers
Like input devices, output devices can be connected to a computer using cables or a wireless connection

11. Output Devices - Printers
Printers produce a paper copy often call hard copy
Laser printers – a temporary laser image is transferred onto paper with a powdery substance called toner
Inkjet printers – spray ink onto paper
Dot matrix printers – transfer ink to the aper by striking a rubbon with pins.

12. Investigating Data Processing
All data and programs are stored as files
A file is a named collection of stored data
An executable file contains the instructions that tell a computer how to perform a specific task
A data file is created by a user with software

13. Investigating Data Processing
A computer cannot understand characters used in human language
Like a light bulb, a computer interprets every signal as either “on” or “off” . These numbers are referred to as binary digits or bits
A series of eight bits is called a byte
A kilobyte (KB or simply K) is one thousand bytes
A megabyte (MB) is one million bytes
A gigabyte (GB) is one billion bytes
A terabyte (TB) is one trillion bytes

14. Binary Representations of Numbers 1 2 3 4 5 6 7 8 :
253
254
255

15. Investigating Data Processing
Personal computers commonly use the ASCII (pronounced ASK-ee) system which stands for the American Standard Code for Information Interchange
Computers translate ASCII into binary data so they can process the data

16. Sample ASCII code representing letters and symbols
Character
ASCII Code
Binary Number
(space) 32 $ 36 A 65 B 66 97 98 ?
129
163
217 É
233

17. Understanding Memory Types of memory include the following:
Random access memory (RAM) –
temporarily holds programs and data while the computer is on and allows the computer to access that information randomly.
Consists of chips on cards that plug into the motherboard.
When the computer is off RAM is empty
Cache memory (RAM cache or CPU cache) –
Special high speed memory chip on the motherboard that stores frequently accessed and recently accessed data and commands

18. Understanding Memory
Virtual memory – space on the computer’s storage devices that simulate additional RAM.
It is much slower than RAM
Read only memory (ROM) – is a chip on the motherboard that has been prerecorded with data that gives instructions (BIOS or basic input/output system) used to check the computer system’s components to make sure they are working and to activate the essential software that controls the processing function when the computer is turned on or booted up.
ROM never changes and it remains intact when the computer is turned off. It is called non-volatile or permanent memory

19. Understanding Memory
Complimentary metal oxide semiconductor (CMOS, pronounced “SEE-moss”) memory – chip installed on the motherboard that is activated during the boot process and identifies where essential software is stored.
A small rechargeable battery powers CMOS so its contents are saved when the computer is turned off. CMOS changes every time you add or remove hardware on your computer system but does not empty when the computer is shut off
The date and time are stored in CMOS
Often referred to as semi permanent memory

20. Understanding Storage Media
The types of storage media are:
Magnetic storage devices
Hard disk – magnetic oxide-covered metal platters sealed inside the computer
Tape – used to make back-up copies of data stored on hard drives
Optical storage devices – polycarbonate discs coated with a reflective metal on which data is recorded using laser technology
CD (Compact disc) – can store 700 MB of data
DVD- can store between 4.7 and 15.9 GB of data
Blu-ray discs and HD-DVD – can store between 15 and 50 GB of data

21. Understanding Storage Media
Flash Memory
Flash memory cards – used in digital cameras, handheld computers and other devices
USB flash storage device – can store 32 MB – 16 GB of data. Popular for use as a secondary or backup storage device for date stored on a hard disk drive