Keyboards

Of all the components that make up a microcomputer, you will become most familiar with the keyboard. It will probably be your primary means for inputting programs and data on microcomputers.

Keyboards come in many shapes and sizes, have different numbers and arrangements of keys, differ in respect to touch, and have special keys to allow you to communicate specific software commands. Most manufacturers have designed their keyboards as separate devices so you can place them wherever it is convenient. Other manufacturers have designed their keyboards into the display/monitor device or system unit.

The important things you need to know about keyboards are the types of keys and the function and placement of each. All keyboards have the alphabetic characters (upper and lower case), numbers, and some special characters. In addition, keyboards have special function keys and control keys that are defined by the operating system or the program. We will briefly describe an example keyboard and explain some of the more common keys you are likely to use.

LETTERS, NUMBERS, AND SPECIAL

CHARACTER KEYS.\ The arrangement of letter, number, and special character keys may vary. The QWERTY keyboard shown in figure 1-15 has the same format as the conventional typewriter.

Figure 1-15.\QWERTY keyboard.

Figure 1-16.\Control keys.

CONTROL KEYS.\ In looking at figure 1-16, you will notice several keys are outlined in bold. These are some of the more common control keys you can expect to use when working with just about any keyboard. Beginning in the top left-hand corner, you see the ESC(ape) key, TAB key, CTRL (control) key, SHIFT key, ALT (alternate) key, and to the immediate right are the SPACE BAR and the CAPS LOCK key. On the right-hand side of the keyboard are the BACK SPACE key and the ENTER/RETURN key. Depending on what program/software you are using, the keys may be assigned different functions.

ESCape KEY The ESCAPE key usually stops the execution of a program or function

TAB KEY The TAB key moves the cursor to the next tab stop position.

CTRL KEY The CONTROL key performs special functions within the system/program. It is used in combination with other keys to increase the number of functions you can specify to a system or program. For example, on most IBM compatible systems, when used with the ALT and DEL keys, it reboots the operating system.

SHIFT KEY The SHIFT key works in conjunction with other keys. When you hold down the shift key (or depress the CAPS LOCK key) and press a letter key, the letter will be displayed and stored in UPPER CASE. When you hold down the shift key with the number keys on the row above the alphabetic keys, the special characters shown on the top of each key will be displayed and stored. The CAPS LOCK key on this particular keyboard contains a light within the key itself. When it is lit, you know the caps lock feature is on.

ALT KEY The ALTERNATE key also works in conjunction with other keys to increase the number of functions you can communicate to the system/program.

SPACE BAR Press the SPACE BAR whenever you want to enter a blank character, a space.

BACK SPACE KEY Pressing the BACK SPACE key moves the cursor one position to the left, erasing the character that was previously entered.

ENTER/RETURN KEY By pressing the ENTER/RETURN key, you tell the computer (microprocessor) you have entered data or instructions and are ready for processing. Depressing this key also returns the cursor to the beginning of the next line.

SPECIAL FUNCTION KEYS.\ If you look at figure 1-17, you will notice once again several keys outlined in bold. These are special function keys you can expect to use. Located on the far left side of the keyboard, you see 12 special function keys labeled F1 through F12. On some keyboards you will find these function keys have been placed across the top of the keyboard, above the letters and numbers. The number of these function keys may also vary. To the right of the keyboard is another group of special function keys.

Figure 1-17.\Special function keys.

These include a 10 key (0-9) numeric keypad and the cursor control keys. Also, beginning on the top row at the right, you see the NUM(eric) LOCK key, SCROLL LOCK key, PAUSE key, and the PRT SC (print screen) key. Located on the bottom right-hand side of the keyboard are the INS(ert) and DEL(ete) keys. The purpose/function of each of these keys is as follows:

FUNCTION KEYS F1-F12 These special-purpose keys are used to communicate special functions to the operating system, such as MS-DOS, or to applications software. The meaning of each is defined by the particular software. This simplifies tasks that might otherwise require several keystrokes. These keys can also be used with other keys to increase the number of functions you can specify to a program.