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Defining Computers • Computer – an electronic device that:
• Receives data (input)
• Processes data
• Stores data &
• Produces a result (output)
• Information Processing Cycle – the action of these four basic operations
Components of a Computer
• Input Devices
• System Unit (Processor and Memory)
• Output Devices
• Storage Devices
Input Devices
• Input Device – any hardware component that allows you to enter data and instructions into a computer
• Examples:
• Keyboard
• Mouse
• Audio Input
• Web Cam
• Scanner
• Camera
System Unit
• System Unit – A case that contains electronic components of the computer used to process data
Processor
• Processor – Interprets and carries out the basic instructions that operate a computer; Central Processing Unit (CPU) or the brains of the computer
• Control Unit – directs and coordinates most of the operations in the computer; the boss
• Arithmetic/Logic Unit (ALU) – performs arithmetic, comparison, and other operations
Units of Speed
Unit Characters
Hertz Approx. 1 character
Kilohertz Approx. 1,000 characters
Megahertz Approx. 1,000,000 characters
Gigahertz Approx. 1,000,000,000 characters
Terahertz Approx. 1,000,000,000,000 characters
Memory
• Memory – consists of electronic components that store instructions waiting to be executed and data needed by those instructions
• RAM – Random Access Memory or main memory
• Keeps data and instructions temporarily or will erased when the computer is shut off (Measured in bytes)
• ROM – Read Only Memory
• Can be read but not modified (system files)
Units of Memory
Unit Character
Byte Approx. 1 character
Kilobyte Approx. 1,000 characters
Megabyte Approx. 1,000,000 characters
Gigabyte Approx. 1,000,000,000 characters
Terabyte Approx. 1,000,000,000,000 characters
Output Devices
• Output Devices – Hardware components that convey info to one or more people
• Examples:
• Monitors
• CRT
• LCD panel
• Gas plasma display
• Printers (dpi/ppm)
• Laser
• Inkjet
• Speakers
Connecting Input & Output Devices to the Computer • Port – an interface to which
a peripheral device attaches to or communicates with the system unit
• Universal Serial Bus (USB) – the most common used port for devices
• FireWire – used for high speed digital and audio devices
Identifying Types of Storage Devices
Storage Device Description Examples
Magnetic Discs Use magnetic particles to store items on a disk’s surface
Hard disks, magnetic tape, 3½ inch & ZIP disks
Optical Storage Devices
Use laser technology to read and write data on silver platters
CDs and DVDs
Solid-State Storage Media
Removable medium that uses integrated circuits to process
Miniature mobile storage media, USB flash drive
Network Drives Drive located on a computer other than the user’s local system
Classifying Computers
Types Definition Examples
Desktop Computers
Designed so that all components fit on or under a desk
PC (Windows based) or Apple Macintosh
Notebook (Laptop) Computer
Small, portable, personal computers that contain the monitor with a built-in keyboard
Server Used by small to medium-size companies and can support a few users or hundreds of users
File server, database server, or web server
Classifying Computers
Types Definition Examples
Mobile Devices
Generally fit in the palm of your hand
Calculators, smart phones, cell phones, handheld games, electronic organizers, & PDAs
Classifying Computers
Types Definition Examples
Tablet PC A personal computer similar in size and thickness to a notepad
Tablet Devices
Use an embedded operating system, but do not support full feature operating systems like Tablet PCs
Classifying Computers
Types Definition Examples
Mainframe computer
Large expensive computer, capable of supporting up to thousands of users
Super-computer
Fastest type of computer, used for specialized applications to process enormous amounts of data
Classifying Computers
Types Definition Examples
Embedded Computers
Found in devices to perform specific tasks
Digital watch, MP3 player, appliances, etc.
Portable music/ media players
Store and play back music and videos
MP3 players and portable DVD players
Classifying Computers
Types Definition Examples
Computer game systems
Specialized computers used to play games
Electronic book readers
Displays an electronic version of a traditional print book
Computer Performance Factors
• Microprocessor – the faster the processor, the more instructions it can process
• RAM – larger memory allows the processor to move faster
• Hard disk – the bigger and faster the hard drive, the faster the data is processed
• Video – having adequate video memory allows the processor to perform to its full potential