Monday, 26 February 2018

Computer

WHAT IS A COMPUTER?

Computer is a device that transforms data into meaningful information. Data can be anything like marks obtained by you in various subjects. It can also be name, age, sex, weight, height, etc. of all the students in a class.
Computer can also be defined in terms of functions it can perform. A computer can
i) accept data,
ii) store data,
iii) process data as desired, and
iv) retrieve the stored data as and when required and
v) print the result in desired format.
The major characteristics of a computer are high speed, accuracy, diligence, versatility and storage.

Computer Organisation

The block diagram of computer is shown in Fig.

The computer performs basically five major operations of functions irrespective of their size and make. These are
1) it accepts data or instruction by way of input,
2) it stores data,
3) it can process data as required by the user,
4) it gives results in the form of output, and
5) it controls all operations inside a computer. We discuss below each of these operations.
1. Input: this is the process of entering data and programs into the computer system.
Input unit Output unit
Memory Unit
Control Unit
Arithmetic Logic Unit.
2. Control Unit (CU):
The process of input, output, processing and storage is performed under the supervision of a unit called 'Control Unit'. It decides when to start receiving data, when to stop it, where to store data, etc. It takes care of step -by-step processing of all operations in side the computer.
3. Memory Unit:
Computer is used to store data and instructions.
4. Arithmetic Logic Unit (ALU):
The major operations performed by the ALU are addition, subtraction, multiplication, division, logic and comparison.
5. Output:
This is the process of producing results from the data for getting useful information. The ALU and the CU of a computer system are jointly known as the central processing unit (CPU). You may call CPU as the brain of any computer system.

Sunday, 25 February 2018

Types of Input and output devices

Input and output devices

 Input devices:

o Keyboard
o Scanner
o Touchpad
o Mouse
o Trackball
o Joystick
o Microphone
o Stylus
o Camera (web, digital)

 Output devices:

o Monitor
o Projector
o Printer
o Plotter
o Speakers
o Earphones

 Device that is both input and output:

oTouchscreen.

Basic Concept Of IT

Basics of the information technology

Information technology (IT) is a technology which uses computers to gather, process, store, protect, and transfer information. Today, it is common to use the term Information and communications technology (ICT) because it is unimaginable to work on a computer which is not connected to the network.

The computer consists of:

 hardware – physical computer parts, palpable and visible
 software – set of commands that are "understandable" to the computer; instructions to its palpable parts, giving orders what to do
Basic principle of computers: Data enters the computer through one or more input devices. The computer then processes the data and transmits the resulting data to output devices. Output devices can be human interfaces such as a screen or another electronic device such as a storage device or computer network.

The system unit consists of the following components:

 Motherboard - MBO
o a computer "backbone" responsible for communication between components and transmission of information
• Central Processing Unit - CPU
o functions: command execution, data transmission, computer function control
o basic characteristics:
• speed (in Mega Hertz (MHz), Giga Hertz (GHz))
• amount of memory (Cache in Bytes)
 Random Access Memory - RAM o a memory container for programs that are currently running and data that is being processed o basic characteristics:
• speed (in MHz, GHz)
• capacity (in Bytes)
• data rate class (DDR SDRAM, SDR SDRAM)
 permanent memory: o Hard Disk Drive - HDD - device (memory) used for permanent data storage
• data is stored on magnetic platters; electromagnetic heads are used for reading and recording data with the exception of the newest disk types called Solid State Drive (SSD)

• basic characteristics:

 disk platters rotation speed (in RPM)
 capacity (in GB)
 connection interface (IDE, SATA) o Floppy Disk Drive - FDD o optical disks - CD, DVD
ITdesk.info – project of computer e-education with open access
ITdesk.info is licensed under a Creative Commons Attribution- Noncommercial-No Derivative Works 3.0 Croatia License. 2/11
 graphics processing units (GPU)
o function: processing and displaying image on the monitor o it consists of a graphics processor and its own working RAM memory o basic characteristics:
• type of graphics processing units (ATI Radeon, Nvidia GeForce, or other)
• RAM size
• connection interface/slot type

 ports:

o Parallel Port
o Serial Port
o Universal Serial Bus (USB)

Wednesday, 21 February 2018