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

Ram and Rom

Memory

The memory considered this section divided in two basic types

• Random access memory (RAM)
• Read only memory (ROM)

The RAM can be explained as a device that temporarily store data. RAM can be read from also written into. The key feature of the RAM is that when power of the computer is switch off the data in the ram in the lost (Volatile Memory)

As access to ram is very much faster than to a permanent storage device, it is an inefficient method to read and write to permanent storage as it will simply slow the processing down a great deal.

ROM as implied by term is a type of memory which can only be read from. This type of memory does not lose its data when the power off the computer is turned off. The most common ROM in the computer is the bios (Basic Input Output System) ROM.

The CMOS (Complementary Metal Oxide Semiconductor) chip is also belongs to volatile memory since it requires power from the battery to retain the data once the computer is turned off.

The parts of Computer system

The parts of Computer system

A Computer can be classified as a device that takes in raw data as input and processes it and provides information as output. The computer also has the ability to store data and information.

The computer system consists of,

Hardware (physical components)

Software

User (people who use the computer)

That are necessary to make the computer function and to processes data in meaningful way and store data.

Hardware components of a computer

Logical design of the components of the computer

The physical components of the computer system are called computer hardware. All hardware components in a computer can be put in to one of these four categories.

• Processor, memory and integrated devices
• Input device
• Output device
• Storage device

The processor

The processor is device that can only follow the instruction given to it by the programmer. Processor is responsible for all the control of computer system like the brain in human. Major difference between the computer and processor and human brain is that it is incapable of

·         Independent and creative thoughts  

·         Generating new ideas

·         Learning

There are many manufactures of processors in the world

• Intel – Pentium, Celeron and Xeon processors.
• Advanced Micro Devices Inc. (AMD) – Duron and Athlon processors
• Centaur Technologies – Cyrix processors for pc
• IBM – PowerPC
• Motorola – Motorola 6800 are processors manufacture for the apple computer

The most modern processors being manufactured are the

• Hyper-threading processors
• 64 – Bit processors