Perhaps you are brand new to computers. If so, you are in luck because Microsoft, the company that wrote Windows 95, wrote the Windows 95 operating system with you in mind. As a matter of fact, Microsoft used several new computer users to thoroughly test Windows 95 during the product's design.
This appendix will not make you an expert at computers. In fact, this appendix only briefly introduces computers. If, however, you have not used a computer much and have no idea what an operating system is, this appendix will certainly make you feel more comfortable in front of your computer. After you finish this appendix, you will have more insight into the world of computers, and you'll understand better how Windows 95 helps you work with your computer.
JUST A MINUTE: Often, desktop and laptop computers are called PCs, which stands for Personal Computers. Whether you have a full-sized desktop PC or a small laptop PC, the background in this appendix applies to either.
Your computer is made up of several hardware components. The hardware consists of the physical devices that you can touch and see. All of the following are hardware devices:
Figure A.1 contains a diagram that illustrates each of these hardware components.
The disk and CD-ROM drives, keyboard, screen, printer, and mouse are often called
peripheral devices because they plug into the system unit and support the
computer's operation. Peripheral devices are either input devices, output
devices, or input/output devices (sometimes called I/O devices),
depending on the data flow direction between the device and the system unit. If data
flows out from the system unit to a device such as the printer, that device is an
output device. The keyboard is an input device because data goes from the keyboard
into the system unit. Disk drives are I/O devices because data flows in both directions
between the system unit and the disk drives.
Figure A.1.
Your computer is made up of many hardware devices.
The system unit is the primary controlling unit of your computer. Often the system unit is a large box that sits on the floor or on your desktop. Many people put their video screens on top of their system units. The system unit holds the following elements:
The system unit is the actual computer. When you buy a computer, try to buy the latest system unit and as much memory as possible, even if it means settling for a less-expensive video screen and printer. Later, you can always upgrade the screen and printer. If you cannot afford more than eight megabytes of memory you can add more later.
The two kinds of disk drives are: Hard disk drives, which are non-removable, fast, and hold a considerable amount of information; and floppy disk drives, which are slower than hard disks and do not hold as much information, but you can use removable diskettes in the floppy disk drives so that you can transfer and share data between two or more computers.
JUST A MINUTE: The term drive refers to the box in which you insert diskettes and CD-ROMs. Hard disk drives contain non-removable disk platters that hold data and programs.
The disk drives provide for long-term memory. When you power off your computer the data on the disks remains on the disks. Like a cassette tape, the data leaves a disk drive only when you issue commands to remove that data. Disk data is often called non-volatile memory. The contents of RAM disappears when you turn off your computer.
The disks and RAM work in tandem with each other. When you need to run a program, such as a word processor, you'll instruct the computer to load that program from a disk drive into RAM memory. Once loaded into RAM, your CPU can then execute the instructions in that program.
JUST A MINUTE: Programs are discussed more fully in a later section.
Disks, even large hard disks, rarely hold as much information as CD-ROM drives. A CD-ROM drive holds compact disks that look just like the audio CDs you've seen and listened to. As a matter of fact, all of today's CD-ROM drives play music from audio CDs as easily as they read data from CD-ROMs that contain computer data and programs. A CD-ROM drive typically holds over 600 million characters of information. Although CD-ROMs are slow, their capacity makes them almost a staple item in today's computers. Multimedia (the audio and video capabilities of computers) often requires the huge storage capacities of CD-ROM drives to hold motion video and sound.
JUST A MINUTE: Memory and disks are measured by their storage capacities. Generally, the more data they hold, the better and more expensive disks and memory are. Today's disks and memory hold so much data that computerists have developed a shortcut that represents the amount of data a device can hold. One character of storage is called a byte. One thousand bytes is often called a kilobyte. Actually one kilobyte (or 1KB for short) is exactly 1,024 bytes because the internal nature of today's digital memory requires that memory amounts fall on a power of 2 boundary. One million bytes is called a megabyte or meg, or M for short. One billion bytes is called a gigabyte or gig for short. Therefore, if a CD-ROM holds approximately 600 million characters of data, that CD-ROM is known as a 600-meg CD-ROM drive.
New kinds of disk drives are appearing every day. Today you can purchase a removable disk drive that falls somewhat between a hard disk and a floppy disk. The storage capacity exceeds that of many hard disks (you can get more than 1 gigabyte of removable disk storage), and these disk drives use removable disk cartridges that act and look a lot like floppy disks. In addition, advanced CD-ROM technology is making CD-ROMs available in a writeable format so that you can record your own CD-ROMs. The CD technology is progressing in storage capacity also so that CDs in the future will be able to hold much more storage than today's.
New users rarely have a problem adapting to computer keyboards because the keyboard
works almost exactly like a typewriter's keyboard. There are several alphanumeric
keys that hold the numbers and letters laid out identically to a typewriter's alphanumeric
keys. Figure A.2 shows a typical computer keyboard.
Figure A.2.
Computer keyboards look like typewriter keyboards with some additional
keys.
The Enter key often works like a carriage return key on a typewriter. You'll sometimes
press Enter at the end of a line to signal that you're finished entering that line
of text. In most word processors, you will press Enter at the end of a paragraph
of text, but not at the end of a line because the word processors usually offer a
feature called word wrap that automatically brings the cursor to the start
of the next line of text as you type.
Often there is a numeric keypad to the right of the keyboard. The numeric keypad contains number keys as well as common operator keys that hold an equal sign, plus sign, minus sign, division sign (a slash), and multiplication sign (an asterisk). The keypad allows for quicker numeric data entry than is possible using the numbers across the top of the alphanumeric section of the keyboard.
There are usually two Shift keys for uppercase letters. To type an uppercase A you would hold Shift, then press A before releasing both keys. Often, such a combined keystroke is referred to as Shift+A. A CapsLock key enables you to lock the keyboard into an uppercase state (all letters appear shifted) until you press CapsLock once again.
In addition to Shift, there are these additional modifier keys: Alt and Ctrl. The Alt key (meaning alternative) and Ctrl (meaning control) give two more levels of shift states. Therefore, you can press A, Shift+A, Alt+A, or Ctrl+A. Different programs use these modifier keys differently. For example, Alt+F might display a list of file options or select an item on the screen.
You'll find 10 or 12 keys labeled F1 through F10 (or F12). They are called function keys. A function key often performs several tasks depending on what you're doing at the time. Each program that you run responds differently to the function keys.
The Esc key (known as the escape key) often lets you back up one step when working on your PC. For example, if you start to print a document you can often press Esc to cancel the printing. As with the function keys, each program that you run handles the Esc key differently.
There are always at least four keys with arrows on them. These are the cursor-movement keys. A cursor is a blinking underscore, straight vertical line, or box, that indicates where the next typed character will appear on the screen. Often you can move the cursor around the screen using the Up, Down, Left, and Right arrow keys.
JUST A MINUTE: Actually there are two cursors. The text cursor (more accurately known as a caret), normally a vertical bar, indicates where the next typed character will appear on the screen. The mouse cursor is usually a pointing white arrow (although Windows 95 lets you change the mouse cursor to a different shape) that indicates the current position of the mouse on the screen.
Four additional cursor-movement keys, the Home, End, PageUp, and PageDown keys move the text cursor around on the screen. Each of these keys behaves differently depending on how the programs you run react to those keystrokes. During the movement of the text cursor, you can often press the Ins and Del keys to change text already on the screen by inserting and deleting text.
The NumLock key is used for converting the numeric keypad from numbers to cursor-movement keys and back again. Hour 18, "Aid via the Accessibility Options," describes a second and more specialized use for NumLock. The ScrollLock key is not used much these days but sometimes controls the scrolling of the screen's display. If you are displaying a large document and only part of that document fits on the screen at one time, you can scroll the screen up and down the document to bring other parts of the document into view.
Windows 95 uses the PrtSc key (meaning print screen--it may be spelled out on your keyboard) to save a copy of the screen. You can later print or store that screen image to the disk drive.
Keyboards often come with built-in mice or trackballs that give you more room on your desk. In addition, companies are manufacturing more ergonomically balanced keyboards. Such keyboards are designed to ease strain on your hands and wrists, and they're a great help for people who use their computers a lot.
The computer's video screen is sometimes called a monitor. These days almost every screen is capable of displaying color graphics. Without color graphics, Windows 95 would be fairly useless. Windows 95 is known as a GUI, or graphical user interface, so graphics are an integral part of the nature of Windows 95.
The quality of graphics is measured by a screen's resolution. The resolution determines the number and density of dots that combine to create graphics and text. The lowest resolution sold today is called VGA (which stands for Video Graphics Array), but most computers support higher resolutions such as super-VGA standards. As long as your monitor is capable of displaying VGA-resolution graphics, you will be able to work with all Windows 95 features.
CAUTION: Your computer's system unit contains a video card into which you plug your video screen. Both your video card and the monitor must be capable of displaying VGA resolution before you will see VGA on your screen.
Many kinds of printers are available. Windows 95 supports over 1,600 printer makes and models. Although many printers exist, almost every printer connected to a PC today falls into one of these three categories:
JUST A MINUTE: You also can find color versions of ink-jet and laser printers. Color ink-jet printers produce fairly good quality output. Color laser printers produce high-quality output, but are fairly expensive.
Although you can enter several kinds of information using the keyboard, the mouse is the fundamental controlling input device for Windows 95. Due to the graphical nature of Windows 95, you need the mouse for pointing and moving graphics around the screen.
JUST A MINUTE: Hour 1, "What's Windows 95 All About?," explains how to use the mouse.
If you have a desktop computer, be sure to clear plenty of room (about one square foot is good) for mouse movement. Some people use a trackball, which is a stationary mouse that takes up less desk space. Many of today's laptop computers contain mice or trackballs that are built into the keyboards or attached to the side of the computer.
The computer's software consists of programs and data. The term program has already been used often in this appendix during the discussion of hardware. Programs fall into the category of software. A program is a set of instructions that direct the computer. The CPU interprets those instructions and either activates one of the hardware devices (such as the printer) or processes data given to the program.
Programs and data reside both on disk drives and in memory. The software on disk drives is safe and remains stored on the disk until you erase the software and data. If you want to run a program (which causes the computer to execute the program's instructions) you'll have to instruct the computer to load the program from the disk into RAM. Only when the program is in RAM can the computer run it.
Windows 95 is an operating system that controls all the computer's input and output. Windows 95 is just a program, but it is a program that controls other programs and that enables you to control your computer. Windows 95 turns the computer into a multitasking computer, which means that you can run more than one program at once. If you want to work on a word processor and print payroll checks, you can do both at the same time by starting both the word processor program and the payroll program.
JUST A MINUTE: The checks produced by the payroll program, as well as the document that you create inside the word processor, make up the data that resides inside the computer's memory at the time.
Figure A.3 shows what your memory looks like when using a computer and Windows 95. Notice that memory is consumed by Windows 95, by one or more programs, and by data sections that go with each program. The amount of memory not used is known as free memory and is available for other programs and data.
JUST A MINUTE: If you do not have enough memory to run several programs at once, Windows 95 can often use disk storage to simulate memory. Windows 95 then swaps data and programs to and from the disk drive as you run the multiple programs. The more memory your computer has, the less swapping that Windows 95 has to perform, and the faster your programs
will run.
Figure A.3
The typical contents of RAM.
All data and programs reside on your disk drive in files. A file is a program
or a data document of related information. Files have unique names to distinguish
them from one another.
Most of this appendix dealt with hardware because the rest of the book explains how to use your computer's software. Windows 95 is the controlling element, and Windows 95 must always be loaded and reside inside your computer before you can take advantage of its features, such as multitasking.
Now that you've been introduced to the computer's elementary hardware and software concepts, you're ready to begin using Windows 95. Turn now to the first hour and start Windows 95. You'll be a productive computer user (and computer lover) quickly!
