Keyboard

Keyboard:

An input device made up of keys, which when struck sends a byte (character) to the computer (or terminal ) and is usually echoed to the screen

Keyboard: A random arrangement of letters stuck on keys!

Use

A device made up of keys, which when struck sends a byte (character) to the computer (or terminal ) and is usually echoed to the screen
Main data entry and control device for the computer user.

Features

IBM enhanced keyboard

Input device consisting of a QWERTY Keyboard, numeric keypad, command or function keys and a cursor pad.
Used to input data into the computer.
Reports whenever a key is pressed or released.
When a key is struck the character is sent to the computer (or front end terminal processor) and usually echoed to the screen
The CPU interprets the 8-bit (ASCII) value sent. This may be a letter, a direction or a function.

When IBM introduced their first PC in the early 1980's, the numerical and direction keys were placed on the same keypad. Using the [Num Lock] key allows the operator to shift from numeric to directional. This legacy still prevails today, with most numeric keypads having the alternative direction keys available via the num lock key. Many portables use this layout, with the inclusion of separate arrow keys, to enable a more compact keyboard.

Enhanced 101 Key Keyboard

An improved design from the standard keyboard, most common now on desktop computers.

Contain four regions;

Qwerty keyboard [Q],[W],[E],..
editing and direction keys [Insert],[Home],.. arrow keys
numeric keyboard [0], [1], ..
function keys [F1], [F2],...

Microsoft Ergonomic Keyboard

A radical redesign but still with the enhanced layout.

Designed to better fit the contours of your hands.

Contains "special" windows keys.

Interaction

Whenever a key is struck

An ASCII code is generated and sent to the CPU

This code is interpreted by the CPU and may be;

sent to the VDU as a character (like "A") to provide feedback to the user, or
used to indicate an action like

bringing up a help screen - [F1] in Windows, or
deleting a character - [delete] or [Backspace], or
Cancel the current operation - [Esc]ape.
moving the cursor - arrow keys.

Qwerty layout

When keyboards were first introduced it was found that a typist would outpace the speed that the mechanical devices could operate at. So in order to "slow the typist down" a "Qwerty" layout was devised. Millions of users later, and after many years of technological advancement, and were still working with this handicapping system.

What are some of the reasons you can think of as to why the Qwerty layout is still the most preferred?

Dvorak layout

In view of the Qwerty layout being designed to handicap the users, a second layout has been developed. The Dvorak layout. Indeed three versions exist; a Two handed, a left single-handed, and a right single-handed for users unable to use both hands. A two handed layout is illustrated above.

References

[Ref 43] MS-DOS 6 Concise User's Guide