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Inside a Personal Computer

As I discuss momentarily, there are a lot of different types of personal computers—desktops, all-in-ones, laptops, and the like. What they have in common is a core set of components—the computer hardware. Unlike computer software, which describes the programs and applications you run on your computer, the hardware is composed of those physical parts of your system you can see and touch.

Well, you could see the parts if you opened the case, which you can’t always do. Let’s take a virtual tour inside a typical PC, so you can get a sense of how the darned thing works.

The Motherboard: Home to Almost Everything

Inside every PC are all manner of computer chips and circuit boards. Most of these parts connect to a big circuit board called a motherboard, so named because it’s the “mother” for the computer’s microprocessor and memory chips, as well as for all other internal components that enable your system to function.

On a laptop or 2-in-1 PC (a laptop that also functions as a tablet), the motherboard is just under the keyboard. On a traditional desktop PC, the motherboard is located somewhere inside the computer’s system unit. (In Figure 1.1, it’s on the left side of the cabinet.) On an all-in-one desktop, it’s typically built into the monitor unit.

Figure 1.1

Figure 1.1 What a typical desktop PC looks like on the inside—a big motherboard with lots of add-on boards attached.

On a traditional desktop PC, the motherboard contains several slots, into which you can plug additional boards (also called cards) that perform specific functions. For example, some gaming PCs feature a separate video card that enables your motherboard to transmit high-quality video signals to your monitor. All-in-one, laptop, and 2-in-1 PCs have these functions built into the motherboard and thus aren’t expandable like PCs that have separate system units.

Microprocessors: The Main Engine

I’m not done talking about the motherboard just yet. That’s because the specific chip that controls your entire computer system is buried somewhere on that big motherboard. This chip is called a microprocessor or a central processing unit (CPU).

The microprocessor is the brain inside your system. It processes all the instructions necessary for your computer to perform its duties. The more powerful the microprocessor chip, the faster and more efficiently your system runs.

Microprocessors carry out the various instructions that enable your computer to compute. Every input and output device connected to a computer—the keyboard, printer, monitor, and so on—either issues or receives instructions that the microprocessor then processes. Your software programs also issue instructions that must be implemented by the microprocessor. This chip truly is the workhorse of your system; it affects just about everything your computer does.

Different computers have different types of microprocessor chips. Desktop and laptop computers running the Windows operating system use chips manufactured by either Intel or AMD. (Apple Macintosh computers also use Intel chips, although they’re different from the chips used in Windows PCs.)

In addition to having different chip manufacturers (and different chip families from the same manufacturer), you’ll run into microprocessor chips that run at different speeds. CPU speed today is measured in gigahertz (GHz). A CPU with a speed of 1GHz can run at one billion clock ticks per second! The bigger the gigahertz number, the faster the chip runs.

It gets better. Most computers today incorporate chips with more than one core. Each core is the equivalent of a separate CPU on a single chip. You can find chips with two, four, or six cores—the equivalent of two, four, or six CPUs working together to increase your processing power. The more cores, the better—especially for processor-intensive tasks, such as editing digital video files.

If you’re shopping for a new PC, look for one with the combination of a powerful microprocessor and a high clock speed for best performance. And don’t forget to count all the cores; a quad-core chip with four 2GHz CPUs is more powerful than a single-core chip with a single 4GHz CPU.

Computer Memory: Temporary Storage

Before a CPU can process instructions you give it, your instructions must be stored somewhere in preparation for access by the microprocessor. These instructions—along with other data processed by your system—are temporarily held in the computer’s random access memory (RAM). All computers have some amount of memory, which is created by a number of memory chips. The more memory that’s available in a machine, the more instructions and data that can be stored at one time.

Memory is measured in terms of bytes. One byte is equal to approximately one character in a word processing document. A unit equaling approximately one thousand bytes (1,024, to be exact) is called a kilobyte (KB), and a unit of approximately one thousand (1,024) kilobytes is called a megabyte (MB). A thousand megabytes is a gigabyte (GB).

Most computers today come with at least 4GB of memory, some with much more. To enable your computer to run as many programs as quickly as possible, you need as much memory installed in your system as it can accept—or that you can afford. You can add extra memory to a computer by installing new memory modules, which is as easy as plugging a “stick” directly into a slot on your system’s motherboard.

If your computer doesn’t possess enough memory, its CPU must constantly retrieve data from permanent storage on its hard disk. This method of data retrieval is slower than retrieving instructions and data from electronic memory. In fact, if your machine doesn’t have enough memory, some programs will run very slowly (or you might experience random system crashes), and other programs won’t run at all!

Hard Disk Drives: Long-Term Storage

Another important physical component inside many computers is the hard disk drive. The hard disk permanently stores all your important data. Some hard disks today can store multiple terabytes (TB) of data, each terabyte equaling 1,000 gigabytes. (Contrast this to your system’s RAM, which temporarily stores only a few gigabytes of data.)

A hard disk consists of numerous metallic platters. These platters store data magnetically. Special read/write heads realign magnetic particles on the platters, much like a recording head records data onto magnetic recording tape.

However, before data can be stored on a disk, including your system’s hard disk, that disk must be formatted. A disk that has not been formatted cannot accept data. When you format a hard disk, your computer prepares each track and sector of the disk to accept and store data magnetically. Fortunately, hard disks in new PCs are preformatted, so you don’t have to worry about this. (And, in most cases, your operating system and key programs are preinstalled.)

Solid-State Drives: Faster Long-Term Storage

Not all long-term storage is hard disk-based. Many of today’s laptop and 2-in-1 PCs and an increasing number of desktop and all-in-one models don’t have traditional hard disk storage. Instead, they use solid-state flash memory for long-term storage.

A solid-state drive (SSD) has no moving parts. Instead, data is stored electronically on an integrated circuit. This type of storage is much faster than traditional hard disk storage; data stored on a solid-state drive can be accessed pretty much instantly. Plus, laptops with solid-state drives are considerably lighter than laptops with traditional hard drives.

The downside of solid-state storage is that it’s a little more expensive than hard drive storage, although it doesn’t cost as much today as it did just a few years ago. What this means is that you typically get a little less storage on an SSD than you would on a similar computer with a traditional hard drive—or you pay a little more for a computer with similarly sized SSD.

So, if it’s important for your computer to be fast and lightweight, consider a model with solid-state storage. If you prefer a lower-priced model or need more storage space, stick with a traditional hard disk PC.

Keyboards: Fingertip Input

Computers receive data by reading it from disk, accepting it electronically over a modem, or receiving input directly from you, the user. You provide your input by way of what’s called, in general, an input device; the most common input device you use to talk to your computer is the keyboard.

A computer keyboard, similar to the one in Figure 1.2, looks and functions just like an old-fashioned typewriter keyboard, except that computer keyboards have a few more keys. Some of these keys (such as the arrow, Pg Up, Pg Dn, Home, and End keys) enable you to move around within a program or file. Other keys provide access to special program features. When you press a key on your keyboard, it sends an electronic signal to your system unit that tells your machine what you want it to do.

Figure 1.2

Figure 1.2 A keyboard for a desktop PC.

Many keyboards that come with desktop and all-in-one PCs hook up via a cable to the back of your system unit. Some manufacturers make wireless keyboards that connect to your system unit via radio signals, thus eliminating one cable from the back of your system. Keyboards on laptop and 2-in-1 PCs are built into the main unit, of course, and the keys are often just a tad smaller than those on desktop PC keyboards.

On a typical Windows PC keyboard, there are a few extra keys in addition to the normal letters and numbers and symbols and such. Chief among these is the Windows key (sometimes called the Winkey), like the one shown in Figure 1.3, which has a little Windows logo on it. In Windows 10, many operating functions are initiated by pressing the Windows key either by itself or along with another key on the keyboard.

Figure 1.3

Figure 1.3 The Windows key on a computer keyboard.

Mice and Touchpads: Point-and-Click Input Devices

It’s a funny name but a necessary device. A computer mouse, like the one shown in Figure 1.4, is a small handheld device that you scoot across your desktop. Most mice consist of an oblong case with two or three buttons on top. When you move the mouse along a desktop, an onscreen pointer (called a cursor) moves in response. When you click (press and release) a mouse button, this motion initiates an action in your program.

Figure 1.4

Figure 1.4 A typical two-button mouse with scroll wheel.

Mice come in all shapes and sizes. Some have wires, and some are wireless. Some are relatively oval in shape, and others are all curvy to better fit in the palm of your hand. Some even have extra buttons that you can program for specific functions or a scroll wheel you can use to scroll through long documents or web pages.

If you have a laptop or 2-in-1 PC, you don’t have a separate mouse. Instead, most laptops feature a touchpad pointing device that functions like a mouse (see Figure 1.5). You move your fingers around the touchpad to move the onscreen cursor and then click one of the buttons underneath the touchpad the same way you’d click a mouse button.

Figure 1.5

Figure 1.5 A touchpad on a notebook PC.

If you use a computer with a touchscreen display, you don’t need a mouse at all. Instead, you control your computer by tapping and swiping the screen, using specific motions to perform specific operations. With a touchscreen computer, operation is fairly intuitive.

Network Connections: Getting Connected

If you have more than one computer in your home, you might want to connect them to a home network. A network enables you to share files between multiple computers, as well as connect multiple PCs to a single printer or scanner. In addition, you use your home network to share a broadband Internet connection so that all your computers (and other devices, like phones and tablets) connect to the Internet.

You can connect computers via either wired or wireless networks. Most home users prefer a wireless network because there are no cables to run from one room of your house to another. Fortunately, connecting a wireless network is as easy as buying a wireless router, which functions as the hub of the network, and then connecting wireless adapters to each computer on the network. (And if you have a laptop PC, the wireless adapter is already built in.)

Sound Cards and Speakers: Making Noise

Every PC comes with some sort of speaker system. Most traditional desktop systems let you set up separate right and left speakers, sometimes accompanied by a subwoofer for better bass. (Figure 1.6 shows a typical right-left-subwoofer speaker system.) All-in-one, laptop, and 2-in-1 PCs typically come with right and left speakers built in but offer the option of connecting external speakers if you want. You can even get so-called 5.1 surround sound speaker systems, with five satellite speakers (front and rear) and the “.1” subwoofer—great for listening to movie soundtracks or playing explosive-laden video games.

Figure 1.6

Figure 1.6 A typical set of right and left external speakers, complete with subwoofer.

All speaker systems are driven by a sound card or chip that is installed inside your system unit. If you upgrade your speaker system, you also might need to upgrade your sound card accordingly. (You can easily switch sound cards on a traditional desktop PC, but it’s really not an option on a laptop or all-in-one.)

Video Cards and Monitors: Getting the Picture

Operating a computer would be difficult if you didn’t constantly receive visual feedback showing you what your machine is doing. This vital function is provided by your computer’s monitor.

Computer monitors today are built around LCD displays, just like you have on your living room TV. On a laptop PC, this display is built into the unit; on a desktop PC, you connect a separate external monitor. And with an all-in-one unit, the display includes the computer motherboard and connections.

You measure the size of a monitor diagonally from corner to corner. Most freestanding LCD monitors today are in the 24" to 27" diagonal range, although both larger and smaller models are also available.

A flat-screen LCD display doesn’t take up a lot of desk space or use a lot of energy, both of which are good things. Most monitors today come with a wide­screen display that has the same 16:9 (or 16:10) aspect ratio used to display widescreen movies—which makes them ideal for viewing or editing movies on your PC. (You also can find some ultrawide monitors, ideal for doing video editing or accounting work, with a 21:9 aspect ratio—but they’re fairly pricey.)

Know, however, that your computer monitor doesn’t generate the images it displays. Instead, screen images are electronically crafted by a video card or chip installed inside your laptop PC or desktop system unit. To work correctly, both the video card and monitor must be matched to display images of the same resolution.

Resolution refers to the size of the images that can be displayed onscreen and is measured in pixels. A pixel is a single dot on your screen; a full picture is composed of thousands of pixels. The higher the resolution, the sharper the resolution—which lets you display more (smaller) elements onscreen.

Resolution is expressed in numbers of pixels, in both the horizontal and vertical directions. Most external monitors today can display 1920—1080 or higher resolution (called full high definition, or FHD). Laptop PC displays are typically smaller (14" to 15.4" diagonal) and sometimes with slightly lower resolution.

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