Understanding Essential Computer Concepts Computer Applications 1

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

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

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

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

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

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

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

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)

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

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.

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

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

Binary Representations of Numbers 00000000 1 00000001 2 00000010 3 00000011 4 00000100 5 00000101 6 00000110 7 00000111 8 00001000 : 253 11111101 254 11111110 255 11111111

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

Sample ASCII code representing letters and symbols Character ASCII Code Binary Number (space) 32 00100000 $ 36 00100100 A 65 01000001 B 66 01000010 97 01100001 98 01100010 ? 129 10000001 £ 163 10100011 ® 217 11011001 É 233 11101001

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

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

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

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

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