About keyboard

Like the mouse, the keyboard is an input device that allows you to talk to the computer. The keyboard is easily recognizable because it resembles a typewriter keypad. If the typewriter predates you, then look for the component that's covered with buttons that have letters, numbers, and symbols on them. If you've ever used a typewriter, you probably recognize many of the keys on a keyboard. In any case, the alphanumeric, symbol, and punctuation keys are self-explanatory. and we'll review the rest of the keys that are unique to a (101-key and 104- key) keyboard. However, we will ignore the three keys found above the numeric keypad (<print screen/ Sys Req>, <Scroll Lock>, and <pause/break>) because they are all fairly useless on most computers today.
Note: If you keyboard includes multimedia and Internet buttons above the keys, consult the manual that comes with your keyboard to learn their functions.

about mouse

A computer would be useless if you had no way to communicate with it. That's why you need an input device. Essentially, an input device lets you talk to your computer. Two examples of input devices are the keyboard and the mouse. We'll discuss keyboards later; for now let's concentrate on the mouse. That funny-looking object that, frankly, looks like a mouse (with its oval body and long tail-like cord connecting it to toe computer) is the mouse. Originally, computers only come with a keyboard. But in 1968 Doug Engelhard invented the mouse. In 1984, Apple Computers introduced the mouse with its Macintosh computers. Shortly thereafter, the mouse was standard equipment on all computers. The mouse acts as a handhold pointing device that allows you to control the actions of that blinking item on your screen known as a cursor.

Memory

most people know that a computer has memory. But what does that relly mean? You often hear techines toss around numbers like "60 GB hard drive. "Okay, that sounds impressive, but what does it tell you? This lesson breaks memory into measurable units.
The first thing you need to know is that, at its most basic level, a computer only understands the concept of "on and Off." On is represented by the number one (1); off is represented by the number zero (0). everything that a computer does is based on this combination of ones and zeros, which is known as the binary system. these ones and zeros are digits, known as bits, which are the smallest memory unit. The term bit is short.

Central Processing Unit (CPU)

Inside the computer case, hidden amongst all the wiring and gizmos, is a particularly important part of the computer known as the central processing unit (of CPU, for short). The CPU is also known as the computer chip (because that's what it is) or the microprocessor (or processor, for short). Some say the CPU is the brain of the computer while others describe it as the heart. In any case, it's the thing that makes you computer a computer. The CPU does all the work: It calculates, it processes, it keeps things running smoothly. You might think of it as a talented stage manager. When it does its behind- the scenes job -well, you don't notice it; you simply enjoy the performance. Originally, CPU's were given wildly inventive names like Chip. Okay, maybe not. The names were actually based on numbers like 8088.

Upgrading a computer

When you upgrade a computer you usually replace older components with new components to improve the performance of a computer. you can also upgrade a computer by adding additional components, such as more memory or a second hard drive. Upgrading a computer to improve its performance is often cheaper than buying a new computer. For most upgrading you will need someone with a lot of computer experience to do the upgrade for you. It's often difficult to determine which is better- upgrading an old computer or simply buying a new computer. If you're an average computer user, plan on buying a new computer every four or five years (sorry -someone has to break this news to you). By then, the of a new computer will be less expensive than any effective upgrades you do.

The Back view of computer (Ports)

when you look at the back of a computer, you may feel a bit overwhelmed by all the slots and holes. Fortunately, manufacturers have added some fairly standard icons and color coding to help you identify what should be plugged into your computer and where. before long, you'll recognize those icons and color and the configuration won't seem so mysterious. it's rather like hooking up cable and a DVD player to the back of your television- unless you're one of those people who just wait for the cable guy to take care of that heinous task. In any case, this topic  will review each item piece by piece so you won't get competely lost. Before we begin, let's define a couple of terms. The first thing you'll notice is that the back of your computer has lots of holes. Those holes are called (depending on who you ask) jacks, ports, or connectors. you may notice that some of the connectors have hoes, but some have what look like stickpins (which are aptly named pins). The ones that have holes are called female connectors; the ones that have pins are called male connectors. Let's leave it at that.

The Front of a computer and Peripheral devices

The system unit or computer case is that plastic box that sits under your monitor or desk and is covered with slots, buttons, and lights. computer cases come in several shapes and sizes. Older computers often have the horizontal desktop case, which has gradually been replaced by the verical tower case. Manufacturers are now phasing out the tallest towers because the compact size of the smallest tower, known as a mini-tower, is attractive to consumers. everything outside of and connected to the system unit is called peripherals. you can add dozens of peripherals and accessories to make it more useful and fun. common peripherals include printers, scanners, external hard drives, CD-ROM drives, and digital cameras. Many peripherals are considered to be input devices, because they allow you to talk to your computer by inputting information. other peripherals are output devices, because they let your computer talk back to you. One more thing: all peripherals are considered to be part of a computer's hardware.