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Computer is an electronic machine that can store, organize and search information, do calculation and control other machines. These other machines are called as computer hardware. Computer hardware, means the physical component of a computer system, which has different functions to complete different tasks. This hardware includes input devices, output devices, a system unit, storage devices, and communications devices. This could be a monitor, memory chip, hard drive, or CPU. Hardware is something we can touch. This compares to software which is not tangible in any way. We cannot pick it up or weigh it. Without software, hardware is useless.
Figure 1 Common computer hardware components
The Components of a Computer
There are five categories of computer hardware which are input devices, output devices, a system unit, storage devices, and communications devices.
An input device is any hardware component that allows us to enter data and instructions into a computer. Keyboard, mouse, microphone, scanner, and Web cam are the commonly used input devices.
Keyboard keys produce letters, numbers or signs (characters). The keyboard is used to type text and numbers into a word processor, text editor or other program.
It is a handheld device. The movement of a pointer on the screen is controlled by using mouse. We make selection on the screen by clicking a mouse.
It allows us to speak into a computer. It converts sound waves into analogous electrical waves.
It converts printed material (such as text and pictures) into a form the computer can use.
It is a digital video camera that allows us to create movies or take pictures and store them on the computer instead of on tape or film.
An output device is any hardware component that conveys information to one or more people. Printer, a monitor, speakers, headphones, and earbuds are commonly used output devices.
Printer produces text and graphics on a physical medium such as paper.
Monitor is a piece of electrical equipment which displays images generated by devices such as computers, without producing a permanent record.
Speakers are attached to computer to generate higher-quality sounds for playing games, interacting with multimedia presentations, listening to music, and viewing movies.
Headphones only allow the individual wearing it hears the sound from computer. Headphones cover outside of the ears.
Earbuds have same function with headphones. The difference is that earbuds rest inside the ear canal.
The system unit is a case that contains electronic components of the computer used to process data. All computers and mobile devices have a system unit. On desktop personal computers, the electronic components and most storage devices are part of the system unit. Processor, memory, adapter cards, drive bays, and the power supply are the electronic components of a system unit.
Processor is also called the central processing unit (CPU), interprets and carries out the basic instructions that operate a computer.
Memory stores instructions waiting to be executed by the processor, data needed by those instructions, and the results of processing the data.
An adapter card is a circuit board that enhances functions of a component of the system unit and/or provides connections to peripherals.
A drive bay is a rectangular opening that typically holds disk drives.
The power supply is the component of the system unit that converts the wall outlet alternating current (AC) power into direct current (DC) power.
A storage device is the computer hardware that records and/or retrieves items to and from storage media. When storage devices write data on storage media, they are creating output. Similarly, when storage devices read from storage media, they function as a source of input. Nevertheless, they are categorized as storage devices, not as input or output devices. Hard disk, memory cards, USB Flash Drives, optical discs, and tape are storage devices.
A hard disk contains one or more flexible, circular platters that use magnetic particles to store data, instructions, and information.
Memory cards enable mobile users easily to transport digital photos, music, or files to and from mobile devices and computers or other devices.
USB Flash Drive
USB flash drive has the same function with memory card.
Optical discs primarily store software, data, digital photos, movies, and music. It is written and read by a laser.
Tape is a magnetically coated ribbon of plastic capable of storing large amounts of data and information at a low cost.
A communication device is any type of hardware capable of transmitting data, instructions, and information between a sending device and a receiving device. At the sending end, a communications device sends the sending device to a communications channel. At the receiving end, a communications device receives the signals from the communications channel. Dial-up modems, digital modems, wireless modems, network cards, wireless access points, routers, and hubs and switches are communications devices.
A dial-up modem converts digital signals to analog signals and analog signals, so that data can travel along an analog telephone line.
A digital modem sends and receives data and information to and from a digital line.
Wireless modem uses the cell phone network to connect to the Internet wirelessly from a notebook computer, a smart phone, or other mobile device.
A network card enables a computer or device that does not have built-in networking capability to access a network.
Wireless access point
A wireless access points allow computers and devices to transfer data wirelessly among themselves or to transfer data wirelessly to a wired network.
A router connects multiple computers or other routers together and transmits data to its correct destination on a network.
Hubs and switches
Hubs and switches receive data from many directions and then forward it to one or more destinations.
The structure of the motherboard
The motherboard, sometimes called a system board, is the main circuit board of the system unit. Many electronic components attach to the motherboard; others are built into it. Figure 2 shows a photo of a current desktop personal computer motherboard and identifies its slots for adapter cards, the processor chip, and memory. Memory chips are installed on memory cards (modules) that fit in a slot on the motherboard.
A computer chip is a small piece of semi-conducting material, usually silicon, on which integrated circuits are etched. An integrated circuit contains many microscopic pathways capable of carrying electrical current. Each integrated circuit can contains many millions of elements such as resistors, capasitors, and transistors. A transistor, for example, can act as an electronic switch that opens or closes the circuit for electrical charges. Todayâ€™s computer chips contain millions or billions of transistors. Most chips are no bigger than one-half-inch square. Manufacturers package chips so that the chips can be attached to a circuit board, such as motherboard or an adapter card.
Figure 2 Diagram of a motherboard
Listed below are the major components of the motherboard and functions:
Another important component is the basic input/output system (BIOS) chip which contains startup programs such as the power on/self-test (POST) and drivers of the computer. This chip controls communication between the systems hardware and operating system. BIOS can also be referred to as firmware.
2) Expansion Slots:
Expansion slots enable the CPU to communicate with the peripheral devices which expand the capability of the computer. Different cards can be plugged into these slots to enhance the computer such as video cards to improve graphics and sound cards to provide better audio.
This battery is referred to as CMOS battery and is responsible for keeping the time and date. It usually has a life span of about 3 to 4 years.
In a computer system, the CPU needs information and instructions to perform properly. This information and instructions for the CPU are stored in Random Access Memory (RAM). This memory is sometimes referred to as Primary Memory or Main Memory.
Ports allow external devices to be connected to the computer motherboard. There are different types of ports located on the motherboard such as parallel, serial, universal serial bus (USB) and SCSI (small computer system interface).
6) Power Connector:
This is a 20-pin male connector located on the computer motherboard. The power supply is plugged into this connector which supplies power for the motherboard, its components and some peripherals.
7) Integrated Graphics and Audio:
Most of the motherboards manufactured include integrated graphics, audio and LAN.
8) Hard Drive Data Transfer Modes-(Interface):
The data transfer rate of a hard drive is the time used to read/write information. This interface mode was upgraded to UDMA/100 and then finally to UDMA/133. These characteristics apply to Parallel ATA hard drives. For a long time, the UDMA/133 remained the fastest interface until the inception of the Serial ATA drive which has a data transfer rate of 150MBS/sec. These have now improved to data transfer rates of 300MBS/sec. These hard drives can be operated in different modes called RAID (Redundant Array of Independent Disks). RAID requires more than one hard drive. This provides speed by writing/reading information to more than one drive simultaneously - called 'striping' (RAID, 0).
A printer is an output device that produces text and graphics on a physical medium such as paper. There are many different types and styles of printers exist with varying speeds, capabilities, and printing methods. Two main kinds of printers are nonimpact printer and impact printer. A non impact printer forms characters and graphics on a piece of paper without actually striking the paper. Some spay ink, while others use heat or pressure to create images. On the other hand, an impact printer forms characters and graphics on a piece of paper by striking a mechanism against an inked ribbon that physically contacts the paper. Impact printers characteristically are noisy because of this striking activity. Commonly used nonimpact printers are ink-jet printers, photo printers, laser printers, thermal printers, mobile printers, label and postage printers, plotters, and large-format printers. Two commonly used types of impact printers are dot-matrix printers and line printers.
A dot-matrix printer produces printed images when tiny wire pins on a print head mechanism strike an inked ribbon.
A line printer is a high-speed impact printer that prints an entire line at a time.
An ink-jet printer forms characters and graphics by spaying tiny drops of liquid ink onto a piece of paper.
A photo printer is a color printer that produces photo-lab-quality pictures.
Laser printers print text and graphics in high-quality resolutions and high-speed.
A thermal printer generates images by pushing electrically heated pins against heat-sensitive paper.
A mobile printer is a small, lightweight, battery-powered printer that allows a mobile user to print from a notebook computer, and smart phone.
Label and postage printer
A label printer is a small printer that prints on an adhesive-type material that can be placed on a variety of items such as envelopes, and packages.
Plotters are sophisticated printers used to produce high-quality drawings such as blue-prints, maps, and circuit diagrams.
Using ink-jet printer technology, but on a much larger scale, a large-format printer creates photo-realistic-quality color prints.
Computer hardware is important. Without computer hardware, a computer is unable to process data into information. Thus, we should be aware of what our computer consists of and how its components operate so as to be able to overcome certain problems that might occur within our PC. The hardware is considered the most important part within a computer because even the software is influenced by it. This is way it is very useful to know about the importance of computer hardware so as to become aware of the necessity of buying good quality components for our PC so that it might function properly.