Review of Storage, Display and Input Devices

1. Review of Storage, Display and Input Devices Written by: Andrea LeShea Georgia CTAE Resource Network 2010

2. Storage Devices • Used to keep data when the power to the computer is turned off. • Medium/media • Location where data is stored.

3. Hard Disk • Usually mounted inside the computer’s system unit. Magnetic Storage • Recording of data onto disks or tape by magnetizing particles of an oxide based surface coating.

4. Floppy Disk • Round piece of flexible Mylar plastic covered with a thin layer of magnetic oxide and sealed inside a protective covering • May be referred to as a “floppy” • 3½ disk capacity is 1.44 MB or 1,440,000 bytes

5. Optical Storage • Means of recording data as light and dark spots on CD or DVD. • Reading is done through a low-power laser light. • Pits • Dark spots • Lands • Lighter, non-spotted surface areas

6. CD-ROM • “CD – Read Only Memory” • Also called CD-R • CD-Read • Storage device that uses laser technology to read data that is permanently stored on compact disks, cannot be used to write data to a disk.

7. CD-RW • “CD-Read Write” • A storage device that reads data from CD’s and also can write data to CD’s. • Similar to a CD-ROM, but has the ability to write to CD.

8. DVD • DVD ROM • Digital Video Disk which is read only. • DVD-R • Digital Video Disk which can be written to one time. It then becomes read only. • DVD-RW • Digital Video Disk which can be rewritten to.

9. Blu-Ray Technology • New standard in storage • Blu-Ray • New disks use blue laser light instead of the red laser light used in traditional CD players. • Disks may ultimately hold • Over 30GB on one-sided disks. • Over 50GB on two-sided disks.

10. Flash or Jump Drives • External storage devices that can be used like a external hard drive. • They have the capability to be saved to, deleted from, and files can be renamed just like with a normal hard drive.

11. List of Devices for Secondary Storage • Magnetic tape and disks • Compact Disk Read-Only Memory (CD-ROM) • Write Once Read Many - (WORM) • Magneto-optical disks • Redundant Array of Inexpensive Disks (RAID) • Optical disks • Digital Video Disks • Memory cards • Flash memory • Removable storage

12. Monitor Overview • Display device that forms an image by converting electronic signals from the computer into points of colored light on the screen. • The most-used output device on a computer. • Most desktop displays use a cathode ray tube (CRT). • Laptops use liquid crystal display (LCD), light-emitting diode (LED), and gas plasma or other image projection technology. • Monitors using LCD technologies are beginning to replace CRT.

13. LCD Technology • Used for displays in notebooks, small computers, pagers, phones and other instruments. • Uses a combination of fluorescent-based backlight, color filters, transistors, and liquid crystal to create and illuminate images. • In 1997, manufactures began to offer full size LCD monitors as alternatives to CRT monitors. • Until recently, was only used on notebook computers and other portable devices.

14. How Monitors Work • Most use a cathode-ray tube as a display device. • CRT: Glass tube that is narrow at one end and opens to a flat screen at the other end. • Narrow end contains electron guns. • Single gun for monochrome and three guns for color. • Display screen is covered with tiny phosphor dots that emit light when struck by the electron gun.

15. Monitor Quality, Resolution and Pixels Quality: • Manufacturers describe quality by dot pitch. • Smaller dot pitches mean pixels are closely spaced which will yield a sharper image. • Resolution: • Indicates how densely packed the pixels are. • The amount of Pixels on the screen. The more pixels the better the resolution. Pixels: • The smallest unit in a graphic image; computer display devices use a matrix of pixels to display text and graphics.

16. Input Devices • Units that gather information and transform that information into a series of electronic signals for the computer.

17. Mouse • An input device that allows the user to manipulate objects on the screen by moving the mouse along the surface of the desk. Keyboard • An arrangement of letters, numbers, and special function keys that act as the primary input device to the computer.

18. Scanner • Light sensing input device that reads printed text and graphics and then translates the results into a form the computer can process. • Allows users to capture data from an original source document and save in an electronic format.

19. Touch Screen • A touch sensitive display device that allows users to interact with devices by touching various areas of the screen. • Examples of Touch Screens: • Smart Phones • Airport Check-In Kiosk • Grocery Store Self Check Out • ATM’s

20. Barcode Reader • A barcode reader (or barcode scanner) is an electronic device for reading printed barcodes. Like a flatbed scanner, it consists of a light source, a lens and a light sensor translating optical impulses into electrical ones.

21. Pointing Device • An input device that allows a user to control a pointer on the screen. • The location and shape change as the user moves the pointing device. • Pointing Devices Include: • Mouse • Trackball • Touchpad

22. Digital Camera • Allows users to take pictures and store images electronically. Smart Phone • A small hand held device that users can enter data and instructions using a variety of techniques.

23. References • Computing Essentials 2005 • M. Guymon. Pleasant Grove High School