What is a computer?
A computer is a very fast electronic machine. It processes the data we feed into it. When we feed the data, it is called input. Feeding data into to the computer is done by input devices like the keyboard, mouse, mike, camera etc. The computer gives back this data to us. This data we call output. The output data is given out to us by the output devices like the monitor, printer, speakers etc.
Some basic terms we must know:
Hardware: These are the physical parts of the computer.
Software: These are the programs or instructions that tell the computer what to do
Data : These can be in the form of letters, numbers, symbols, pictures, videos etc.
Default : The term default is used to tell us that these are the original settings in the computer. This is what will happen if we don’t change anything.
What makes a computer powerful?
(1) Speed :
A computer perform crores of actions per second. Your computer speed is called megahertz, after Heinrich Hertz, a German physicist. Now a days because of the increased speeds of the computers we use the term Giga Hertz (GHz) to determine the speed of the processor. The meaning of 1GHz (Giga-Hertz) is the speed that is equal to 1 billion cycles per second.
(2) Reliability :
The computer is a reliable machine. The failures, if any, are due to human error.
(3) Storage :
A computer can store a very large amount of data. The computers use a storage device to store the data. The storage device can be disk like hard drive disk (HDD), a compact disk (CD), a digital video disk (DVD), a pen drive, a tape etc. These storage drives can be fixed in the computer or can be removable. The data is measured in kilobytes (KB), megabytes (MB), gigabytes (GB) or terabytes (TB) .
CPU or Central Processing Unit : computer chip or microprocessor.
This is the heart of the computer. Nothing in the computer can function without it. It gives instructions to the computer programs to process the data. It analyses and controls the flow of data. The speed of your computer depends on the speed of the microprocessor you use in the computer. Some time we hear the word Cache. Cache is nothing but a very fast random access memory (RAM) that a computer microprocessor can access more quickly than it can access regular RAM.
Power Supply Unit:
There is a power supply unit (PSU) whose switch is located somewhere on the CPU, usually in the front or on the side. You press this switch to start your computer. Remember that this switch is used only to turn on the computer and should not be used to turn off the computer. Turning off your computer from this switch can damage your computer. It is used only if your computer does not turn off otherwise from the Start button because of some defect in the operating system.
Motherboard of a computer is the central printed circuit board (PCB) which supports all the crucial components of any modern computer. It is a plate like base placed at the bottom of the CPU cabinet. It has various types of sockets, slots etc. to fix the computer components on it. Like a mother controlling a family, computer’s motherboard holds and ties all the components of the computer together.
RAM or Random Access Memory Chip:
RAM or Random Accessory Memory is one of the most important component of a computer. It is the primary memory storage device which temporarily stores the data in current use until it is saved to a permanent storage device also called the secondary memory device like hard disk or tape . For this reason, it is also called a volatile or a short memory device. In case a computer shuts off due to an electric failure or a program failure, all the data stored in this memory is lost. This is the reason that we should continually keep on saving our work every now and then. It helps the computer to run various applications because the data in current use can be quickly reached by the computer's processor. It is much faster to read from and write to than the other kinds of storage in a computer. This is why the type and size of RAM you use in your computer increases or decreases the speed of your computer. It is a small thin plate like component.
Monitor or VDU (Video Display Unit) :
The computer monitor is the physical display for your computer. Commonly we call it a monitor. It is also named as a Video Display Unit (VDU). Its function is only to display like a television what is going on inside the processor. They have their own power switch. So, even if you switch off the monitor, your computer will still be working. In order to save power, we usually switch off the monitor in case we don’t want to use the compute temporarily. It has various adjustment control to change contrast, brightness, size, position etc. Before the invent of LCD (Liquid crystal display) monitors, the CRT (Cathode ray tube) monitors were widely used. The trend now is for LCD monitors which is quite lighter and gives you better display.
Most of the computer keyboards look like the keyboards used in typewriters. In addition to the usual keys used in type writers for letters, numbers and symbols, there are very important keys like the Esc, Enter, Backspace, Delete, Alt, Ctrl and Shift, Space bar, Windows, Cursor keys, Function keys, Numerical Pad, There are also keys like the Num Lock, Caps Lock and Scroll Lock etc. In addition to these, the modern keyboards also have various multi-media buttons and power off – on button too. These days we also get wireless remote keyboards.
The mouse is an input device like the keyboard. It works with Left and Right Clicking buttons. You also have scroll button on computer mouse these days. You can double click for executing an action. When you click the right button, a special menu is displayed with various options you can select. All executions are done with the left click. Now a days optical mouse has become very common. We also get a remote control mouse in the market, whereby you operate certain functions of your computer standing away from the computer. These are very useful when you are running PowerPoint slides.
These drives help the permanent storage devices or secondary memory storage devices to run your computer. These come in the form of Floppy Disk Drive (FDD), Hard Disk Drive (HDD), CD Rom Drive (CDR), Zip Drive, CD Writer, DVD Writer, Pen Drives, etc. Floppy Disk Drives (FDD) are fast becoming obsolete now. HDD is a fixed device but we also get portable hard disks now.
Other devices like printer, speakers, mikes, cameras etc.
These input and output devices are used for various purposes like printing, recording and listening to music, to input and watch photos and videos on your computer. Printers come in various types like laser printer, Dot matrix printers; Ink jet printers etc. Similarly speakers also come in various sizes with low and advanced features. We use web cameras and digital still and video cameras as input devices. We also get different type of mikes. Some come with stands and some are used as overhead phones and speakers.
Computer software is a set of instructions compiled in a computer language which we call computer programing. These programs or related data provide the instructions to the computer as to what the computer should do or not do. Anything stored electrically is called a software.
Software can be divided into two categories:
System software :
This includes the operating system like Windows XP, Unix etc. which allow other programs and computer applications to run on them. These serve as play grounds for other players to play.
Application software :
This includes programs that are used by the computer operating system such as word processors, spread sheets, presentations, games, music, videos etc.