This chapter is from the book
This chapter is from the book
This chapter is from the book
Basic Computer Hardware
Computer systems include hardware, software, and firmware. Hardware is something you can touch and feel; the physical computer and the parts inside the computer are examples of hardware. The monitor, keyboard, and mouse are hardware components. Software interacts with the hardware. Windows, Linux, macOS, Microsoft Office, Solitaire, Google Chrome, Adobe Acrobat Reader, and WordPerfect are examples of software.
Without software that directs the hardware to accomplish something, a computer is no more than a doorstop. Every computer needs an important piece of software called an operating system, which coordinates the interaction between hardware and software applications. The operating system also handles the interaction between a user and the computer. Examples of operating systems include Windows 7, 8, 8.1, and 10, macOS, and various Linux systems, such as Red Hat and Ubuntu.
A device driver is a special piece of software designed to enable a hardware component. The device driver enables the operating system to recognize, control, and use the hardware component. Device drivers are hardware and operating system specific. For example, a printer requires a specific device driver when connected to a computer loaded with Windows 7. The same printer will most likely require a different device driver when using Windows 8 or 10. Each piece of installed hardware requires a device driver for the operating system being used. Figure 1.9 shows how hardware and software must work together.
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Figure 1.9 Hardware and software
Notice in Figure 1.9 the operating system kernel. The kernel is the central part of an operating system. The kernel is the connection between hardware and the applications being used.
Software applications are normally loaded onto the hard drive. When a user selects an application, the operating system controls the loading of the application. The operating system also controls any hardware devices (such as the mouse, keyboard, monitor through the video adapter, and printer) used with the application.
Firmware is a combination of hardware and software, such as electronic chips that contain software: The chip is physical, which is hardware, and it has software built into the chip. An example of firmware is the basic input/output system (BIOS) chip. The BIOS always has startup software inside it that must be present for a computer to operate. This startup software locates and loads the operating system. The BIOS also contains software instructions for communication with input/output devices, as well as important hardware parameters that determine to some extent what hardware can be installed. For example, the system BIOS has the ability to allow other BIOS chips that are located on adapters (such as the video card) to load software that is loaded in the card’s BIOS.
A PC typically consists of a case (chassis), a keyboard that allows users to provide input into the computer, a monitor that outputs or displays information (shown in Figure 1.10), and a mouse that allows data input or is used to select menus and options. Figure 1.10 shows a computer monitor, which may also be called a flat panel, display, or screen.
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Figure 1.10 Computer monitor
When the computer cover or side is opened or removed, the parts inside can be identified. The easiest part to identify is the power supply, which is the metal box normally located in a back corner of a case. A power cord connects the power supply to a wall outlet or surge strip. One purpose of the power supply is to convert the outlet AC voltage to DC voltage used internally in the PC. The power supply distributes this DC voltage using power cables that connect to the various internal computer parts. A fan located inside the power supply keeps the computer cool to prevent damage to the components.
A personal computer usually has a device to store software applications and files. Two examples of storage devices are the hard drive and optical drive. The hard drive, sometimes called the hard disk, is a rectangular box normally inside the computer’s case that is sealed to keep out dust and dirt. The hard drive has no external opening. The computer must be opened in order to access a hard drive. A DVD drive, or optical drive, holds discs (compact discs, or CDs), digital versatile discs (DVDs), or Blu-ray discs (BDs) that have data, music, video, or software applications on them. The front of the optical drive has a tray that would eject outward so a disc may be inserted. Figure 1.11 shows the major components of a tower computer. Figure 1.12 shows a hard drive. Figure 1.13 shows an optical drive. Figure 1.14 shows a power supply. The hard drive in Figure 1.12, optical drive in Figure 1.13, and power supply in Figure 1.14 all are shown as they would look before being installed into the computer case. Figure 1.15 shows a tower computer case.
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Figure 1.11 Tower computer
Figure 1.12 Hard drive
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Figure 1.13 DVD or optical drive
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Figure 1.14 Power supply
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Figure 1.15 Tower case
The motherboard is the main circuit board inside a PC and contains the most electronics. It is normally located on the bottom of a desktop or laptop computer and mounted on the side of a tower computer. Other names for the motherboard include mainboard, planar, or system board. The motherboard is the largest electronic circuit board in the computer. External devices connect directly to the back of the motherboard or ports on the front of the computer. Figure 1.16 shows a motherboard when it is not installed inside a computer as well as memory and an adapter, which are covered next.
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Figure 1.16 Computer motherboard
The motherboard holds memory modules. Memory is an important part of any computing device. Memory modules hold applications, part of the operating system, and user documents. Random access memory (RAM) is the most common type of memory and is volatile—that is, the data inside the module is lost when power is removed. When a user types a document in a word processing program, both the word processing application and the document are in RAM. If the user turns the computer off without saving the document to removable media or the hard drive, the document is lost because the information does not stay in RAM. (Note that some applications have the ability to periodically save a document, but this is not a guarantee that it has the latest information.) Figure 1.17 shows memory modules when they are not installed into the motherboard memory slots. Look back to Figure 1.16 to see the memory modules installed in the motherboard. Memory is covered in great detail in Chapter 6, “Memory.”
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Figure 1.17 Memory modules
A device may have a cable that connects the device to the motherboard. Other devices require an adapter. An adapter is an electronic card that plugs into an expansion slot on the motherboard. Other names for an adapter are controller, card, controller card, circuit card, circuit board, and adapter board. Adapters allow someone to add a functionality or enhancement that is not provided through the ports on the motherboard. An example is someone who wants better sound or video graphics, or additional ports of some type in order to connect external devices. Figure 1.18 shows an adapter. Notice how the contacts at the bottom are a particular shape. Chapter 3, “On the Motherboard,” goes into more detail about the types of expansion slots and adapters. You can also look back to Figure 1.16 to see a video adapter installed into a motherboard expansion slot.
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Figure 1.18 Adapter
The following are the generic steps for installing adapters:
Step 1. Always follow the manufacturer’s installation directions. Use an antistatic wrist strap when handling adapters. Electrostatic discharge (ESD) can damage electronic parts. (See Chapter 5, “Disassembly and Power,” for more details on ESD.)
Step 2. Be sure the computer is powered off and unplugged.
Step 3. Remove any brackets from the case or plastic covers from the rear of the computer that may prevent adapter installation. Install the adapter in a free expansion slot and reattach any securing hardware.
Step 4. Attach any internal device cables that connect to the adapter, as well as any cables that go to an external port on the adapter.
Step 5. Attach any internal or external devices to the opposite ends of the cable, if necessary.
Step 6. Power on any external devices connected to the adapter, if applicable.
Step 7. Reattach the computer power cord and power on the computer.
Step 8. Load any application software or device drivers needed for the devices attached to the adapter.
Step 9. Test the device connected to the adapter.
See Figure 1.19 for an illustration of a motherboard, expansion slots, memory, and an adapter in an expansion slot.
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Figure 1.19 Motherboard with expansion slots and an adapter
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