Devices Of the Computer

Input devices

Any device that can feed data or information to a computer system is referred to as an input device.

The user can use devices like the keyboard, mouse or trackball and joystick to provide commands and data into the computer.

Device like, the microphone, scanner and digital cameras help the processor to receive data from its environment.

Output devices

                     
Any device that can be used to output information from the computer system is known as an output device.

Devices like the Monitor or LCD panel and projectors display information whereas a speaker would provide audible output. A feedback joystick would provide an output which can be felt by the user. Any device that can be used to output information from a computer is known as an output device.

some devices have functionality that fall into both input and output categories.

• Touch-screen display
• A feedback joystick

Storage Devices

Previously data was stored in punch cards (a card with holes punched representing 1s and 0s)

the magnetic tape was one of the earliest forms of data storage device but had a disadvantage since it had to be accessed in a sequential manner.

The introduction of hard disk and floppy disk made it possible for data to be stored and accessed (randomly).

The hard disk was not meant to be portable and was known as fixed disk located inside the computer.

External hard disks were developed but not for the purpose of portability since they were fragile and prone to strong vibrations.

Portable magnetic storage devices like floppy disk had a very limited storage capacity, this was changed with the invention of the ZIP disk which could store over 100 megabytes (1048576 bytes is 1 megabyte).

The invention of the Optical storage disks like the CD ROM and the DVD ROM made it possible to store data on disks which were not affected by magnetic fields, was easier to transport, and cost effective to produce.

The typical CD ROM could store around 700 megabytes whereas the DVD ROM could store in excess of 4.2 gigabytes and now with improved Blu-ray (blue laser) format storage can go up to 27 gigabytes.

The size of all of these disks was somewhat cumbersome (with every device invented in the modern world becoming smaller and much more portable).

With this requirement new disk and memory like the flash-drive (pen drive), SD card, 7 Compact-Flash, Sony Memory stick and the XD picture-card have emerged. Some 3 of these devices have a capacity that could exceed 12 gigabytes and are commonly used for storage in small digital devices