Category How does It works, How things work, How is it done, Curiosity

WHAT IS THE DIFFERENCE BETWEEN HARDWARE AND SOFTWARE?

The hardware of a computer consists of all the parts you can hold in your hand: the machine itself and any other machinery that is attached to it. But a computer by itself is simply a collection of components. In order to do anything at all, it must be programmed (given a set of instructions). Programs are what are known as software. They are written in a code that a computer can “understand” and act upon. The codes in which programs are written are sometimes called languages.

Computer hardware is any physical device used in or with your machine, whereas software is a collection of programming code installed on your computer’s hard drive. In other words, hardware is something you can hold in your hand, whereas software cannot be held in your hand. You can touch hardware, but you cannot touch software. Hardware is physical, and software is virtual.

For example, the computer monitor you are using to read this text, and the mouse you are using to navigate this web page are computer hardware. The Internet browser allowing you to view this page, and the operating system that the browser is running on are considered software. A video card is hardware, and a computer game is software. You can touch and feel the video card, and the computer uses it to play a computer game, but you cannot touch or feel the programming code that makes up the computer game.

All software utilizes at least one hardware device to operate. For example, a video game, which is software, uses the computer processor (CPU), memory (RAM), hard drive, and video card to run. Word processing software uses the computer processor, memory, and hard drive to create and save documents.

Hardware is what makes a computer work. A CPU processes information and that information can be stored in RAM or on a hard drive. A sound card provides sound to speakers, and a video card provides an image to a monitor. Each of these are examples of hardware components.

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WHAT ARE THE MAIN PARTS OF A COMPUTER?

The central processing unit (CPU) is the “brain” of a computer, where its calculations take place. It is contained within a larger processing unit. In order to give instructions to the computer, input devices, such as a keyboard, stylus, mouse, or joystick, are needed. The monitor enables the user to see data on a screen. Many other machines, called peripherals, can also be connected to the computer. They include printers, scanners and modems.

The Central Processing Unit

The central processing unit, or CPU, can be thought of as the “brain” of a computer. Using a combination of arithmetic functions, logic processes and input/output commands, the CPU receives instructions from various computer programs in use and executes them as needed. The modern CPU exists in the form of a microprocessor, which features a single integrated circuit design. This is a dramatic departure from the earliest CPU units, which featured a transistor-based construction. Compared to the CPUs used in the second half of the 20th century, modern hardware is highly efficient, portable and relatively inexpensive to manufacture.

The Motherboard

A CPU can’t achieve its intended purpose without the assistance of the motherboard. The motherboard is a printed circuit board, or PCB, found inside a computer which not only hosts the CPU but also acts as a connected gateway to various other computer peripherals, including sound cards, hard drives, video cards and so on. The motherboard hosts a number of sockets into which microprocessors, such as the CPU, can be plugged. The motherboard is also connected to the computer’s power supply and distributes electrical voltage to the attached components. Simply put, a motherboard provides a critical platform on which the rest of a CPU’s hardware can operate. Without the motherboard in place, a computer couldn’t function.

Hard Drives and RAM

The hard drive often shortened to HD, stores data which can then be accessed by various other programs at any given time. Hard drives provide users with various levels of storage capacity, with more expensive units often providing greater space for data storage and faster rates of data transmission.

It’s somewhat easy to confuse the function of the hard drive with that of random access memory, or RAM. Unlike a hard drive, RAM is composed of a series of chips which allow for temporary data storage only. Whereas a hard drive will continue to store data even after a computer has been powered off, RAM will be cleared. RAM is often used to act as a holding zone for open files or critical data that a program may need to access intermittently during use. RAM should not be thought of as storage, per say, but instead as a “place holder” for valuable information. Nevertheless, it remains one of the 4 main parts of a computer that is still in use today.

Monitor

The monitor works with a video card, located inside the computer case, to display images and text on the screen. Most monitors have control buttons that allow you to change your monitor’s display settings, and some monitors also have built-in speakers.

Keyboard

The keyboard is one of the main ways to communicate with a computer. There are many different types of keyboards, but most are very similar and allow you to accomplish the same basic tasks.

Mouse

The mouse is another important tool for communicating with computers. Commonly known as a pointing device, it lets you point to objects on the screen, click on them, and move them. There are two main mouse types: optical and mechanical. The optical mouse uses an electronic eye to detect movement and is easier to clean. The mechanical mouse uses a rolling ball to detect movement and requires regular cleaning to work properly.

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WHO BUILT THE FIRST COMPUTER?

In the early 1830s, an English inventor called Charles Babbage (1792-1871) designed the first programmable computer and began to build it. In fact, he never finished, as the machine was extremely complicated! This computer was entirely mechanical. Over a hundred years had to pass before the electronic components that are used today were invented.

We could argue that the first computer was the abacus or its descendant, the slide rule, invented by William Oughtred in 1622. But the first computer resembling today’s modern machines was the Analytical Engine, a device conceived and designed by British mathematician Charles Babbage between 1833 and 1871. Before Babbage came along, a “computer” was a person, someone who literally sat around all day, adding and subtracting numbers and entering the results into tables. The tables then appeared in books, so other people could use them to complete tasks, such as launching artillery shells accurately or calculating taxes.

It was, in fact, a mammoth number-crunching project that inspired Babbage in the first place [source: Campbell-Kelly]. Napoleon Bonaparte initiated the project in 1790, when he ordered a switch from the old imperial system of measurements to the new metric system. For 10 years, scores of human computers made the necessary conversions and completed the tables. Bonaparte was never able to publish the tables, however, and they sat collecting dust in the Academia des sciences in Paris.

In 1819, Babbage visited the City of Light and viewed the unpublished manuscript with page after page of tables. If only, he wondered, there was a way to produce such tables faster, with less manpower and fewer mistakes. He thought of the many marvels generated by the Industrial Revolution. If creative and hardworking inventors could develop the cotton gin and the steam locomotive, then why not a machine to make calculations [source: Campbell-Kelly]?

Babbage returned to England and decided to build just such a machine. His first vision was something he dubbed the Difference Engine, which worked on the principle of finite differences, or making complex mathematical calculations by repeated addition without using multiplication or division. He secured government funding in 1824 and spent eight years perfecting his idea. In 1832, he produced a functioning prototype of his table-making machine, only to find his funding had run out.

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HOW DOES A LOUDSPEAKER PRODUCE SOUND?

A loudspeaker works like a reversed microphone. Electric current flows into a coil of wire, turning it into an electromagnet. This attracts the coil to another magnet inside the loudspeaker, causing the coil to vibrate. This vibrates a diaphragm at the same frequency as the original sound, pushing air in front of it to carry the sound to the ears of the listeners. Many loudspeakers can be connected together, so that sound is heard all around a large outdoor or indoor space.

A loudspeakers (loud-speaker or speaker) is an electroacoustic transducer which converts an electrical audio signal into a corresponding sound.

A loudspeaker consists of paper or plastic moulded into a cone shape called ‘diaphragm.’ When an audio signal is applied to the loudspeaker’s voice coil suspended in a circular gap between the poles of a permanent magnet, the coil moves rapidly back and forth due to Faraday’s law of induction. This causes the diaphragm attached to the coil to move back and forth, pushing on the air to create sound waves.

Voice coil, usually made of copper wire, is glued to the back of the diaphragm. When a sound signal passes through the voice coil, a magnetic field is produced around the coil causing the diaphragm to vibrate. The larger the magnet and voice coil, the greater the power and efficiency of the loudspeaker.

The coil is oriented co-axially inside the gap; the outside of the gap being one pole and the centre post (called as the pole piece) being the other. The gap establishes a concentrated magnetic field between the two poles of the permanent magnet. The pole piece and backplate are often a single piece, called the pole plate.

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HOW DO MICROPHONES WORK?

Inside a microphone is a metal disc, called a diaphragm. When a sound wave hits the sensitive diaphragm, it makes it vibrate at the same frequency. This causes a wire coil, beneath the diaphragm, to move up and down. As the coil comes near to a magnet below, it creates a pulse of electric current in the wire. The pattern of these pulses matches the pattern of the sound wave. The pulses can be sent along a wire to a loudspeaker, to be turned back into sound, or they can be recorded on a tape or compact disc.

When you speak, sound waves created by your voice carry energy toward the microphone. Remember that sound we can hear is energy carried by vibrations in the air. Inside the microphone, the diaphragm (much smaller than you’d find in a loudspeaker and usually made of very thin plastic) moves back and forth when the sound waves hit it. The coil, attached to the diaphragm, moves back and forth as well.

The permanent magnet produces a magnetic field that cuts through the coil. As the coil moves back and forth through the magnetic field, an electric current flows through it.

The electric current flows out from the microphone to an amplifier or sound recording device. Hey presto, you’ve converted your original sound into electricity! By using this current to drive sound recording equipment, you can effectively store the sound forever more. Or you could amplify (boost the size of) the current and then feed it into a loudspeaker, turning the electricity back into much louder sound. That’s how PA (personal address) systems, electric guitar amplifiers, and rock concert amplifiers work.

Dynamic microphones are just ordinary microphones that use diaphragms, magnets, and coils. Condenser microphones work a slightly different way by using a diaphragm to move the metal plates of a capacitor (an electric-charge storing device) and generate a current that way. Most microphones are omnidirectional, which means they pick up sound equally well from any direction. If you’re recording something like a TV news reporter in a noisy environment, or a rare bird tweeting in a distant hedgerow, you’re better off using a unidirectional microphone that picks up sound from one specific direction. Microphones described as cardioid and hypercardioid pick up sounds in a kind of “heart-shaped” (that’s what cardioid means) pattern, gathering more sound from one direction than another. As their name suggests, you can target shotgun microphones so they pick up sounds from a very specific location because they are highly directional. Wireless microphones use radio transmitters to send their signals to and from an amplifier or other audio equipment (that’s why they’re often called “radio mics”).

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HOW DOES A COMPACT DISC WORK?

A compact disc (CD) has a plastic surface on which sounds are stored in binary code as very small holes, called pits, and flat areas, called lands. These can be “read” by a laser beam. The laser beam scans across the surface of the disc. When the light falls on a pit, it is scattered, but when it falls on a land, it is reflected back to a light-sensitive detector. This in turn causes a pulse of current to pass to a loudspeaker, which converts it back into sound.

If you have read the HowStuffWorks article How CDs Work, you know that the basic idea behind data storage on a normal CD is simple. The surface of the CD contains one long spiral track of data. Along the track, there are flat reflective areas and non-reflective bumps. A flat reflective area represents a binary 1, while a non-reflective bump represents a binary 0. The CD drive shines a laser at the surface of the CD and can detect the reflective areas and the bumps by the amount of laser light they reflect. The drive converts the reflections into 1s and 0s to read digital data from the disc. See How CDs Work for more information.

Normal CDs cannot be modified — they are read-only devices. A CD-R disc needs to allow the drive to write data onto the disc. For a CD-R disk to work there must be a way for a laser to create a non-reflective area on the disc. A CD-R disc therefore has an extra layer that the laser can modify. This extra layer is a greenish dye. In a normal CD, you have a plastic substrate covered with a reflective aluminum or gold layer. In a CD-R, you have a plastic substrate, a dye layer and a reflective gold layer. On a new CD-R disc, the entire surface of the disc is reflective — the laser can shine through the dye and reflect off the gold layer.

When you write data to a CD-R, the writing laser (which is much more powerful than the reading laser) heats up the dye layer and changes its transparency. The change in the dye creates the equivalent of a non-reflective bump. This is a permanent change, and both CD and CD-R drives can read the modified dye as a bump later on.

It turns out that the dye is fairly sensitive to light — it has to be in order for a laser to modify it quickly. Therefore, you want to avoid exposing CD-R discs to sunlight.

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