Section 1 7 th Grade Keyboarding

(p. 4) Types of Computers A computer is an electronic device that accepts input, processes data, stores data and produces output. Data are the words, figures, sounds and graphics that describe people, events, things and ideas to produce output. Supercomputer  most powerful, largest and fastest  Ex – predict hurricanes Mainframes  Used by business and government to process large amount of information  Ex – payroll checks for thousands or maintain records for millions of citizens

Types of Computers Personal Computers  Desktop computer-designed to sit on a desk  Laptop computer-portable  Smaller, less powerful Handheld Computers (PDA’s)  Fit in palm of hand  Most have fewer capabilities

Personal Computer Hardware Computer Case-CPU, “brains” Monitor-screen Keyboard Mouse Memory-storing, “remembering” instructions Disk Drive – reading/storing information Speakers

Input, Output, and Storage Devices

(p. 6) Computer Input Devices Hardware that allows you to communicate with your computer.  Keyboard/Ergonomic keyboard  Mouse/Wireless mouse  Trackball-similar to mouse, ball on topside  Track Point-device used to move pointer by pushing up, left, right or down  Touchpad – drag finger over to control pointer  Touch screen – use fingers to make selections  Scanner  Microphone  Bar Code reader/scanner

(p. 8) Computer Output Devices Monitor-size measured diagonally from one corner to the other  CRT  Flat panel/LCD Printer  Dot matrix-ribbon striking pins  Inkjet-spray ink unto paper, output similar to laser, cheaper than laser  Laser-fastest, most expensive, uses powdery substance called toner Speaker

(p. 14) Magnetic Storage Devices Use oxide coated plastic storage media called mylar  Floppy disk, hard disk, tape drives Floppy disks (3 ½” diskettes) – flat circles of iron-coated plastic enclosed in a hard plastic case Hard disk drive – contains several iron-oxide covered metal platters sealed in a case inside the computer. Tape drive– resemble video or audio tapes – used to back up large quantities of stored information, very slow.

(p. 16) Optical and Flash Storage Optical storage devices use laser technology to read and write data on silver platters.  Examples – CD’s, DVD’s  CD’s – first optical storage device, up to 700 MB  DVD’s – store up to 9.4G of data depending upon whether data is stored on both sides and how many layers on data each side contains Flash Drives – plug directly into USB drive, portable, large storage capacity 32MB to 6 GB