Computer Devices

Basic Operations of a Computer – Input, Process and Output

Input – The process of entering the data and instruction to computer for processing.

Process – It refers to processing in CPU on the data, as per the given instructions.

Output – The process of output of the data from the computer system to user.

Input Devices

Keyboard – It is like a typewriter keyboard with 101 keys arranged in 5 groups as

Mouse – A pointing device used to position the pointer, to create graphics, for click and drag-and-drop. Ball or optical mouse is connected by PS/2 port or USB port to computer.

Scanners – It converts printed image to electronic form by using light.

Touch Screens, Voice Recognition Devices are also some other input devices.

Output Devices

Monitor – It is similar to television giving a soft copy output. Earlier monochrome or Colour CRT monitors were used but now LED & LCD.

Printers – It produces hard copy output on paper like laser or inkjet printers.

Storage Devices
It is consist of primary and secondary memory.
Primary Storage Devices – It is internal storage and consists of cache, ROM & RAM.
RAM (Random Access Memory) – It is read/write volatile memory storing temporary data in MB.
ROM (Read Only Memory) – It stores data permanently which can only be read like BIOS.
Cache – It is used for speeding up the data supply to CPU and stores frequently used data in KB.

Secondary Storage Devices – It is usually external storage and consists of disk and flash.
Hard Disk Drive – It is used for mass storage with direct access. It is non-volatile in sizes like 3.5”, 5.5” and 8”. It has disk platters on a spindle, with read/write head having 250-1024 GB capacity.
Optical Disk – Laser beam burns disk surface to write and low power reflected beam to read. It has speed rating or data transfer speed where 1X refers to 150 Kbps. CD-ROM and DVD are examples with 700 MB and 4.3 GB capacity. Blue ray is upcoming technology with 50 GB data.
Flash Memory – It uses semiconductor memory and is used in USB drives, memory cards, etc.
Data can be read or written to it and device can be detached to transfer or move data.
Central Processing Unit (C.P.U) – It executes given commands and is the mind of computer.

Disk Organization Terms
Boot Record – It is in the first sector of disk drive, from where the operating system is loaded into the memory when the computer is started.
Disk partitioning – Process of creating primary and extended partitions on disk drive.
File System – It is a way to organize data on storage device (hard disk) and like NTFS, FAT, etc
File Allocation Table (FAT) – It is a file system used by MS-DOS and MS-WINDOWS.