Neon-komputadór

Keyboards and Mice

Keyboards are undoubtedly the most primary input component for users to enter commands and data into the system. The IBM 101 key Enhanced Keyboard is the de-facto industry standard, however it is challenged by the augmented 104 key Windows keyboard. All are pretty much the same, consisting of four sections; a typing area, a numeric keypad, cursor and screen control and function keys. The Windows keyboard also has left-windows key, a right-windows key and an applications key for additional shortcuts that will be discussed in detail in the third chapter.

A keyboard consists of a set of switches mounted as the key matrix. When a switch is pressed, a processor inside the keyboard (yes, the keyboard is a computer too!) identifies which key is pressed and how long it is pressed (to identify multiple keystrokes). The keyboard processor uses a non-standard serial link in 11-bit packets (8 data bits, plus control bits). Because the system determines what the actual matrix is translated to, it is relatively easy to adopt international characters - this can be found in the Windows Language option for example on the Keyboard control panel.

Keyboards use various switch technologies for each keystroke, the most common being mechanical switches, then foam, rubber and membrane. Mechanical switches simply consist of a top, a spring/clip and a contact on a circuit board. They are very durable and offers resistance to the keystrokes. In comparison foam witches included a piece of foam between the spring mechanism and the circuit board. Rubber keyboards are an elaboration on the foam style that has a carbon button rather than a spring. This type of keyboard resists corrosion very well and has the fewest parts. Membrane keyboards are a variation on the rubber dome. The keys themselves are not separate but are formed together on a single sheet that sits on top of a rubber dome. Sealed from the elements, these keyboards are not particularly well-suited for touch typing, but are very good for operating in conditions where other keyboards would soon fail.

Caring for Keyboards and Mice

The two most common problems with keyboards are stuck keys and defective labels. The former come on during the POST stage of BIOS, usually simply stating 'Keyboard stuck key failure' - sometimes it will even mention which key it is, although this error often comes up when a keyboard isn't plugged in properly, so this should also be checked. Most BIOS errors have a specific code for this however, like 'keyboard cable error'.

To keep a keyboard in top condition they should be cleaned with a soft brush and vacuum cleaner about once a fortnight. Turn the keyboard upside down to dislodge particles of dust and dirt. If coffee or soft drink is spilled on a keyboard, remove it straight away and clean it with distilled water,and partially disassemble. When it is completely dry, reassemble and reconnect. It should work just fine.

If your mouse is moving in an uneven fashion it's probable that it requires cleaning. Bits of dust and dirt get caught on the ball and are transferred to the rollers thus restricting it's free movement. Cleaning it is relatively simple. Detach the mouse from the computer and turn it mouse upside down, open the access panel and remove the ball. Clean the ball with some soapy water or alcohol cleaner and the rollers with alcohol and cotton buds. When the components are thoroughly dry, reassemble and reattach.

Apart from the keyboard, the mouse is the most popular input device among users. Specifically a pointing device, the mouse was invented a very long time ago in computer history - 1964 to be precise at Stanford University's Research Institute. At that stage it had the rather technical title of 'An X-Y Position Indicator for a Display System' and become commercially known with the introduction of the Apple Macintosh personal computer.

The standard mouse comes with the housing a roller ball that signals movement to the system, buttons (usually two) to make selections, and a cable with interface. The mouse ball sits on two rollers, one indicating x-position, the other the y-position. Many mice are connected through a serial port, although the use of a specific mouse port has become increasingly popular. More recent computer system units use USB ports. Other mice (mouses?) come with no roller ball at all - and nor do they need a mousepad - they operate on an infrared beam to determine the relative X-Y position. Not surprisingly, they don't need much cleaning!