What is a computer? A computer is an automatic, electronic, data-processing machine that takes in facts and figures known as data, and then processes or organizes it in some useful way. Afterwards it outputs, or displays, the results for you to see as information. Keep in mind that data is not information but rather information is derived from accurate data that are entered into a computer. Only after processing, is data transformed into information which is then used for decision making.
When talking about computers, there are two terms which must be correctly distinguished, hardware and software. Hardware is all the parts of a computer that can be seen and touched. Hardware includes the internal components that we do not usually see unless we open up our machine. Software is all of the instructions that a computer uses to do what you ask it to do. Pieces of software are often called programs and an operating system is a suite of programs that help all the other programs run. Think of software as the power behind the hardware. Without software your computer is useless. Likewise, without hardware the software can't exist. Computers do not think for themselves so they need software, which is made to manipulate the computer's hardware in such a way that you, the user, can understand.
A calculator is a simple computer. It is not as complex or versatile as your net book, laptop or desktop computer though. It acquires information as series of key presses and computes the result which is displayed on a small screen. Since calculators are faster than humans this creates utility in the form of time saved. They can also repeat processes much more easily than humans can.
Many people mistakenly think that the part of the computer that normally displays pictures and text is the computer. This is usually not true. That part is called the monitor. The computer is usually a box . Also, you may call the whole assembly of all the hardware (the computer and the monitor, for example) the computer. Occasionally though, the computer and monitor are built together, in which case they are commonly referred to as All-in-One Desktop Computers.
There are different types of monitors. One of these is the one already shown. It is called a CRT monitor. It takes more power than the other popular kind, called LCDs . However, CRT monitors work faster, which makes them better for fast games because the movement will blur less. LCDs are thinner than CRTs, but they are generally more expensive.
Monitors are only one way the computer can output information for you to see. Another popular output device is called a printer . Printers are used to put data on paper. This is called hard copy, what monitors show is called soft copy. Computers can also output sounds through speakers; this is also soft copy.
There are also different kinds of input hardware. The two most important of which are the mouse and the keyboard. A mouse is used to move the cursor (or arrow) around the screen (monitor display). A keyboard is used to enter (type) letters, numbers, and other symbols into a computer.
Computers store all data in binary code, which is a number system that only uses ones and zeros. One digit in binary code is called a bit, eight bits is called a byte. A byte is the amount of space one letter takes up. One thing to bear in mind is that all the extra detail about how the letter looks must also be stored in binary code and so word processor documents use more space than one byte per letter.
There are many different kinds of computers. The ones that most people use are called Personal Computers (PCs). Desktop PCs are computers that you don't move around; they generally are a box with a monitor attached. Smaller, portable, computers that are about the size of a briefcase are called laptops or notebooks. There are also computers that are around the same size, but they have a special screen: Text (letters and numbers) is written directly on the screen, these are called Tablet PCs. They also do not require a mouse; the mouse gestures and clicks are done right on the screen with your finger, or a Stylus. Personal Digital Assistants (PDAs) are computers so small that you can hold them in one hand. They generally also have a Touch Screen, like the Tablets. Notebooks, PDAs, and most Tablets have batteries so that you can use them where there is no power. These batteries generally last for about three to four hours before needing to be recharged. They use LCD screens because LCDs are thinner and take less power, so the batteries will last longer, and so that they are not, say, a foot thick. There are also much more powerful computers called mainframes that can be as big as a room or a house! This is what, say, Google and Wikimedia run their websites off of.
Now we will do something basic with the computer, turn it on and back off again! First, turn the power on (using the button or switch on the computer), and turn the monitor on too. After awhile and an assortment of on-screen pictures and words that may flash by, some form of login screen or dialog box should come up. You do not need to worry much about what it is for now. It may not appear at all, or it may be in another variation.
If it comes up, and it is like this one, you must type the correct login name and password in the respective boxes. Then press the enter key, or click on (put the cursor on top of and push the left button on the mouse) the OK button if there is one. If the box does not come up, do not worry, nothing is wrong. That just means the computer is set not to have a password. We will learn more about this later. If this box did not come up, but instead a screen that says ‘Welcome’ somewhere came up, click the picture with the correct user name beside it, type in the password (if there is one), and push the key on your keyboard that says ‘Enter’ or ‘Return’.
To turn the computer off, move your mouse to the bottom of the screen. Usually, in the bottom left-hand corner it will say ‘Start’. Click on that, and a menu should pop up. In the bottom of the menu you will see ‘Turn Off Computer'. Click on this. A box like Figure 1.8 will come up, just click on (1). If a screen comes up that says ‘It is now safe to turn off your computer’, then flip the power-switch, otherwise your computer will turn off automatically. It can often damage the hardware of your computer to switch it off at the plug without following this procedure first.