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| Computers Parts |
What is a Computer?
>>A computer is a programmable machine. The two principal characteristics of a computer are:
- It can execute a prerecorded list of instructions (a program).
Modern Computers:
>> Modern computers are electronic and digital. The actual machinery -- wires,transistors, and circuits -- is called hardware; the instructions and data are called software.
All general-purpose computers require the following hardware components:
>> Enables a computer to store, at least temporarily, data and programs.
>> Allows a computer to permanently retain large amounts of data. Common mass storage devices include disk drives and tape drives.
>> Usually a keyboard and mouse, the input device is the conduit through which data and instruction enter a computer.
>> A display screen, printer, or other device that lets you what the computer has accomplished.
>>The heart of the computer, this is the component that actually executes instructions.
DEFINITIONS:
>> Just like humans, computers rely a lot on memory. They need to process and store data, just like we do. However, computers store data in digital format, which means the information can always be called up exactly the way it was stored. Also, unlike our memory, the computer's memory doesn't get worse over time.
While memory can refer to any medium of data storage , it usually refers to RAM, or random access memory. When your computer boots up, it loads the operating system into its memory, or RAM. This allows your computer to access system functions, such as handling mouse clicks and keystrokes, since the event handlers are all loaded into RAM. Whenever you open a program, the interface and functions used by that program are also loaded into RAM.
RAM is a very high-speed type of memory, which makes it ideal for storing active programs and system processes. It is different than hard disk space in that RAM is made up of physical memory chips, while hard disks are magnetic disks that spin inside a hard drive. Accessing RAM is much faster than accessing the hard disk because RAM access is based on electric charges, while thehard drive needs to seek to the correct part of the disk before accessing data. However, all the information stored in RAM is erased when the computer's power is turned off. The hard disk, on the other hand, stores data magnetically without requiring any electrical power. For more information on the difference between RAM and hard disk space, view this Help Center article.
Another common type of memory is flash memory, which is typically used for small devices such as digital cameras , USB keychain drives, and portable music players like the iPod nano. This kind of memory, known as "electrically erasable programmable read-only memory" (EEPROM), is convenient for portable devices, since it stores information even when its power source is turned off, but is smaller and more resilient than a hard drive.
To summarize, memory is a vital part of the way computers and many electronic devices function. While memory and RAM can often be used synonymously, it is good to know about other types of memory as well. Hopefully you will be able to store the information you've learned in your own memory.
>> Most of the processing done on a computer is done via the computer's central processing unit, or CPU. So in order to give the CPU a break and help it run more efficiently, a video card can be used to process the graphics portion of the processing load. Because most of today's programs are graphically oriented, the video card can help almost any program run more efficiently. However, the difference in performance is especially noticeable in image editing applications and 3D games .
Video cards, also called graphics accelerators, can speed up both 2D and 3D graphics rendering. Programs such as photo editors and Web browsers may benefit from 2D acceleration, while CAD design programs and video games will most likely benefit from the card's 3D acceleration. Some programs rely so heavily on the video card, that they will not run if a supported video card is not installed.
Most video cards support the OpenGL and DirectX libraries. These libraries include commands for manipulating graphics that programmers can include in their code. Some of these commands may include moving or rotating an object, morphing polygons, or casting light and creating shadows. By using standard OpenGL or DirectX functions, it makes it easier for developers to create graphically-oriented programs. Of course, it also makes it necessary for the computer to include a supported video card in order for the program to run.
Video cards are typically installed in either the PCI or AGP slots in the back of a computer. Most computers come with a video card installed in one of these slots, which means it can be upgraded at a later time.
>> Stands for "Heat Sink and Fan." Nearly all computers have heat sinks, which help keep the CPU cool and prevent it from overheating. But sometimes the heat sink itself can become too hot. This can happen if the CPU is running at full capacity for an extended period of time or if the air surrounding the computer is simply too hot.
Therefore, a fan is often used in combination with the heat sink to keep both the CPU and heat sink at an acceptable temperature. This combination is creatively called a "heat sink and fan" or HSF. The fan moves cool air across the heat sink, pushing hot air away from the computer. Each CPU has a thermometer built in that keeps track of the processor's temperature. If the temperature becomes to hot, the fan or fans near the CPU may speed up to help cool the processor and heat sink.
>> The hard drive is what stores all your data. It houses the hard disk , where all your files and folders are physically located. A typical hard drive is only slightly larger than your hand, yet can hold over 100 GB of data. The data is stored on a stack of disks that are mounted inside a solid encasement. These disks spin extremely fast (typically at either 5400 or 7200 RPM) so that data can be accessed immediately from anywhere on the drive. The data is stored on the hard drive magnetically, so it stays on the drive even after the power supply is turned off.
The term "hard drive" is actually short for "hard disk drive." The term "hard disk" refers to the actual disks inside the drive. However, all three of these terms are usually seen as referring to the same thing -- the place where your data is stored. Since I use the term "hard drive" most often, that is the correct one to use.
>> The motherboard is the main circuit board of your computer and is also known as the mainboard or logic board. If you ever open your computer, the biggest piece of silicon you see is the motherboard. Attached to the motherboard, you'll find the CPU, ROM, memory RAM expansion slots , PCI slots, and USBports. It also includes controllers for devices like the hard drive, DVD drive, keyboard, and mouse. Basically, the motherboard is what makes everything in your computer work together.
Each motherboard has a collection of chips and controllers known as the chipset. When new motherboards are developed, they often use new chipsets. The good news is that these boards are typically more efficient and faster than their predecessors. The bad news is that older components often do not work with new chipsets. Of course, if you are planning on upgrading multiple components, it may be more cost-effective to just buy a new computer.
>> A power supply is a hardware component that supplies power to an electrical device. It receives power from an electrical outlet and converts the current from AC (alternating current) to DC (direct current), which is what the computer requires. It also regulates the voltage to an adequate amount, which allows the computer to run smoothly without overheating. The power supply an integral part of any computer and must function correctly for the rest of the components to work.
You can locate the power supply on a system unit by simply finding the input where the power cord is plugged in. Without opening your computer, this is typically the only part of the power supply you will see. If you were to remove the power supply, it would look like a metal box with a fan inside and some cables attached to it. Of course, you should never have to remove the power supply, so it's best to leave it in the case.
While most computers have internal power supplies, many electronic devices use external ones. For example, some monitors and external hard drives have power supplies that reside outside the main unit. These power supplies are connected directly to the cable that plugs into the wall. They often include another cable that connects the device to the power supply. Some power supplies, often called "AC adaptors," are connected directly to the plug (which can make them difficult to plug in where space is limited). Both of these designs allow the main device to be smaller or sleeker by moving the power supply outside the unit.
Since the power supply is the first place an electronic device receives electricity , it is also the most vulnerable to power surges and spikes. Therefore, power supplies are designed to handle fluctuations in electrical current and still provide a regulated or consistent power output. Some include fuses that will blow if the surge is too great, protecting the rest of the equipment. After all, it is much cheaper to replace a power supply than an entire computer. Still, it is wise to connect all electronics to a surge protector or UPS to keep them from being damaged by electrical surges.
