A monitor displays text, graphics, and videos on a screen. Speakers allow you to hear music, voice, and other audio sounds. The circuitry of the system unit usually is part of or is connected to a circuit board called the motherboard. Two main components on the motherboard are the processor and memory.
The processor also called a CPU central processing unit is the electronic component that interprets and carries out the basic instructions that operate the computer. Memory consists of electronic components that store instructions waiting to be executed and data needed by those instructions. Although some forms of memory are permanent, most memory keeps data and instructions temporarily, which mean its contents, are erased when the computer is shut off.
For example, computers can store hundreds of millions of customer names and addresses. Storage holds these items permanently. A computer keeps data, instructions, and information on storage media.
Examples of storage media are USB flash drives, hard disks, optical discs, and memory cards. Storage devices often function as a source of input because they transfer items from storage to memory.
A USB flash drive is a portable storage device that is small and lightweight enough to be transported on a keychain or in a pocket. The average USB flash drive can hold about 4 billion characters. You plug a USB flash drive in a special, easily accessible opening on the computer. A hard disk provides much greater storage capacity than a USB flash drive. The average hard disk can hold more than billion characters. Hard disks are enclosed in an airtight, sealed case. Although some are portable, most are housed inside the system unit.
An external hard disk is a separate, freestanding unit, whereas you insert and remove a removable hard disk from the computer or a device connected to the computer.
An optical disc is a flat, round, portable metal disc with a plastic coating. A CD can hold from million to 1 billion characters. Some DVDs can store two full-length movies or 17 billion characters. Blu-ray Discs can store about 46 hours of standard video, or billion characters. Some mobile devices, such as digital cameras, use memory cards as the storage media.
Widely used communications devices modem and NIC. Communications occur over cables, telephone lines, cellular radio networks, satellites, and other transmission media. Some transmission media, such as satellites and cellular radio networks, are wireless, which means they have no physical lines or wires. Due to rapidly changing technology, however, the distinction among categories is not always clear-cut.
This trend of computers and devices with technologies that overlap, called convergence, leads to computer manufacturers continually releasing newer models that include similar functionality and features. For example, newer cell phones often include media player, camera, and Web browsing capabilities. As devices converge, users need fewer devices for the functionality that they require.
When consumers replace out dated computers and devices, they should dispose of them properly. A personal computer contains a processor, memory, and one or more input, output, and storage devices. Personal computers also often contain a communications device. Two popular architectures of personal computers are the Desktop Computers and the Mobile Computers.
In many models, the system unit is a tall and narrow tower, which can sit on the floor vertically — if desktop space is limited. Some desktop computers function as a server on a network. Others, such as a gaming desktop computer and home theatre PC, target a specific audience. The gaming desktop computer offers high-quality audio, video, and graphics with optimal performance for sophisticated single-user and networked or Internet multiplayer games. These high-end computers cost more than the basic desktop computer.
Another expensive, powerful desktop computer is the workstation, which is geared for work that requires intense calculations and graphics capabilities. An architect uses a workstation to design buildings and homes. A graphic artist uses a workstation to create computer-animated special effects for full-length motion pictures and video games. Similarly, a mobile device is a computing device small enough to hold in your hand. The most popular type of mobile computer is the Notebook computer.
The following sections discuss the notebook computer and widely used mobile devices. Notebook Computers Laptop A notebook computer, also called a laptop computer, is a portable, personal computer often designed to fit on your lap.
Notebook computers are thin and lightweight, yet they can be as powerful as the average desktop computer. A netbook, which is a type of notebook computer, is smaller, lighter than and often not as powerful as a traditional notebook computer. Most netbooks cost less than traditional notebook computers, usually only a few hundred dollars. An ultra-thin is another type of notebook computer that is lightweight and usually less than one-inch thick.
Some notebook computers have touch screens, allowing you to interact with the device by touching the screen, usually with the tip of a finger. On a typical notebook computer, the keyboard is on top of the system unit, and the monitor attaches to the system unit with hinges. These computers weigh on average from 2. Most notebook computers can operate on batteries or a power supply or both.
A digital pen looks like a small ink pen but uses pressure instead of ink. Users write or draw on a Tablet PC by pressing a finger or digital pen on the screen, and issue instructions by tapping on the screen. One design of Tablet PC, called a convertible tablet, has an attached keyboard.
Another design, which does not include a keyboard, is called a slate tablet and provides other means for typing. Some Tablet PCs also support voice input so that users can speak into the computer.
Tablet PCs are useful especially for taking notes in lectures, at meetings, conferences, and other forums where the standard notebook computer is not practical. Instead, these devices store programs and data permanently on special memory inside the system unit or on small storage media such as memory cards.
You often can connect a mobile device to a personal computer to exchange information between the computer and the mobile device. Some mobile devices are Internet-enabled, meaning they can connect to the Internet wirelessly. With an Internet-enabled device, users can chat, send e- mail and instant messages, and access the Web. Because of their reduced size, the screens on mobile devices are small, but usually are in colour. Popular types of mobile devices are smartphones and PDAs, e-book readers, handheld computers, portable media players, and digital cameras.
Smart Phones and PDAs Offering the convenience of one-handed operation, a smart phone is an Internet enabled phone that usually also provides personal information management functions such as a calendar, an appointment book, an address book, a calculator, and a notepad.
In addition to basic phone capabilities, a smart phone allows you to send and receive e-mail messages and access the Web usually for an additional fee. Some smart phones communicate wirelessly with other devices or computers. Many also function as a portable media player and include built-in digital cameras so that you can share photos or videos with others as soon as you capture the image. Many smart phones also offer a variety of application software such as word processing, spreadsheet, and games, and the capability of conducting live video conferences.
Others have a built-in mini keyboard on the front of the phone or a keyboard that slides in and out from behind the phone. Some have touch screens, where you press objects on the screen to make selections and enter text through an on-screen keyboard. Others include a stylus, which is similar to a digital pen but smaller and has less functionality. Types of messages users send with smart phones include text messages, instant messages, picture messages, and video messages.
A phone that can send picture messages often is called a camera phone. A phone that can send video messages often is called a video phone. A PDA personal digital assistant , which often looks like a smart phone, provides personal information management functions such as a calendar, an appointment book, an address book, a calculator, and a notepad.
A PDA differs from a smart phone in that it usually does not provide phone capabilities and may not be Internet-enabled, support voice input, have a built-in camera, or function as a portable media player.
As smart phones and PDAs continue a trend of convergence, it is becoming increasingly difficult to differentiate between the two devices. This has led some manufacturers to refer to PDAs and smart phones simply as handhelds. E-Book Readers An e-book reader short for electronic book reader , or e-reader, is a handheld device that is used primarily for reading e-books. In addition to books, users typically can purchase and read other forms of digital media such as newspapers and magazines.
Most e-book readers have a touch screen and are Internet-enabled. These devices usually are smaller than tablet computers but larger than smart phones. Many handheld computers communicate wirelessly with other devices or computers and also include a digital pen or stylus for input. Some handheld computers have miniature or specialized keyboards.
Many handheld computers are industry-specific and serve the needs of mobile employees, such as meter readers and parcel delivery people, whose jobs require them to move from place to place. Game Consoles A game console is a mobile computing device designed for single-player or multi-player video games.
Weighing on average between two and nine pounds, the compact size of game consoles makes them easy to use at home, in the car, in a hotel, or any location that has an electrical outlet.
A handheld game console is small enough to fit in one hand, making it more portable than the standard game console. With the handheld game console, the controls screen, and speakers are built into the device. Because of their reduced size, the screens are small — three to four inches. Some models use cartridges to store games; others use a memory card or a miniature optical disc. Many handheld game consoles can communicate wirelessly with other similar consoles for multiplayer gaming.
Servers can support from two to several thousand connected computers at the same time. In many cases, one server accesses data, information, and programs on another server.
In other cases, people use personal computers or terminals to access data, information, and programs on a server. A terminal is a device with a monitor, keyboard, and memory. Mainframes store tremendous amounts of data, instructions, and information. Most major corporations use mainframes for business activities. With mainframes, enterprises are able to bill millions of customers, prepare payroll for thousands of employees, and manage thousands of items in inventory. One study reported that mainframes process more than 83 percent of transactions around the world.
Mainframes also can act as servers in a network environment. Servers and other mainframes can access data and information from a mainframe. People also can access programs on the mainframe using terminals or personal computers. The fastest supercomputers are capable of processing more than one quadrillion instructions in a single second. With weights that exceed tons, these computers can store more than 20, times the data and information of an average desktop computer.
Applications requiring complex, sophisticated mathematical calculations use supercomputers. Large-scale simulations and applications in medicine, aerospace, automotive design, online banking, weather forecasting, nuclear energy research, and petroleum exploration use a supercomputer.
Embedded computers are everywhere — at home, in your car, and at work. The following list identifies a variety of everyday products that contain embedded computers. Because embedded computers are components in larger products, they usually are small and have limited hardware. These computers perform various functions, depending on the requirements of the product in which they reside.
Embedded computers in printers, for example, monitor the amount of paper in the tray; check the ink or toner level, signal if a paper jam has occurred, and so on. Any part that we can see or touch is the hard ware. Display Unit, printer etc. So, what else is required? It requires a set of instructions that tells the computer what is to be done with the input data. In computer terminology, this set of instructions is called a program and one or more programs are termed as software.
Software used for computers may be of different types. The computer understands only machine language i. The software which does this translation is known as the system software. Examples of system software are compilers and interpreters. Some are linked by expansion cards in expansion slots on the motherboard or connected directly on the ports via a cable attached on them.
It has additional keys to handle special functions required by a computer. Alphanumeric keys Comprises of alphabets A-Z , numbers and other characters. Special keys They perform specific functions. The Shift key when pressed with another key; alters the meaning of any alphanumeric key for e. Ctrl, Alt and Del pressed together restarts the system. The Esc key is generally used to return to the previous menu or quit a program. The Cursor is a symbol displayed on the screen at the position where text or graphics will be inserted or deleted.
The Cursor movement keys move the cursor on the screen. The Num-Lock is used to activate the numeric keys on the Numeric keypad. The Print Screen is used to print whatever is displayed on the screen. Enter or Return is used to communicate the end of an instruction or data being keyed in through the keyboard. Caps lock is used for keying upper case alphabets.
Backspace is used to erase the character to the left of the cursor position. The Function keys are used to perform a set of operations using a single keystroke.
The function keys can be defined as special purpose keys. In most of the software, pressing the F1 key will take you to the help feature. Other than these keys, 3 status indicators are present on the keyboard.
There are two type of keyboard. Standard keyboard and Enhanced keyboard. A mouse may have one, two or three buttons. The function each button depends on the program. Hardware is any part of the computer that you can touch.
The seeming miles of wires that get tangled on your desk, the CD drive, the monitor are all hardware. Software is a set of electronic instructions consisting of complex codes Programs that make the computer perform tasks. Windows is a software, so is any other program that runs on your computer. While there are thousands of parts even in the smallest computers that make up its hardware, you are not required to know them all.
You only need to know about basic computer hardware. The CPU is considered the brain of the computer. It performs all types of data processing operations, stores data, intermediate results and instructions program. It controls the operation of all parts of computer. A CPU has 3 components as listed below. Think of the ALU as the logical part of the brain. The ALU thinks in bits i. It is made up of a group of memory locations built directly into the CPU called registers. These are used to hold the data binary information that are being processed by the current instruction.
Primary memory is memory that is part of the computer itself and necessary for its functioning. It consists of mainly two types of memories:. As soon as the machine is switched off, data is erased. RAM is volatile. Volatile means that the data stored in memory is lost when we switch off the computer or if there is a power failure. There are different types of RAM available. Some of them are described below. The memory from which we can only read but cannot write on it. This type of memory is non-volatile.
The information is stored permanently in such memories during manufacture. A ROM, stores such instructions that are required to start a computer. This operation is referred to as bootstrap. The different types of ROM are given below. All notes are automatically saved. New sticky notes are created from an icon located in the icon tray next to the computer's clock.
AIDA64 Extreme provides detailed information about software and hardware components in your system. It also offers diagnostic functions and support for overclocking. This program can be used to monitor the hardware sensors in real-time; you can see the temperature of hard disks, CPU, graphics card, motherboard, etc. It not only edits existing PDF files, but it can also help you organize them and create new ones. It comes with an extra set of interesting tools to search and replace text across documents, merge PDF files, or identify text that has been scanned into a PDF file OCR support.
As its name suggests, PerformanceTest is a benchmarking application. It includes several tests to gauge performance and compare it against statistical data gathered about other PCs at world level.
The tool has a very nice and intuitive interface, which makes it very easy to access each of the tests or run them altogether. However, it should be made more responsive to window resizing. This program allows you to obtain information about your system in an easy and fast way. You only need to select the corresponding tab System or Component , and push the button of the element, the information for which you want to obtain.
Then, you can print that info for future reference or give it to the technical assistance provider. If you notice your computer is running slow, this typically is due to the memory RAM running out of usable space.
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