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Building your PC:
The Keyboard and Mouse
Introduction
Currently the keyboard and mouse remain the main means by which the user interacts with their PC. Despite the advent of speech and hindwriting recognition software and hardware the keyboard and mouse will probably remain the dominant means of user input for some time yet. As such they are a very important part of your PC's component list and as you will be spending a considerable amount of time using these devices (and their mis-use is a primary cause of repetitive strain injury [RSI]) it's important that you know a little about these devices and the variants out there so that you can make an imformed choic as to the best versions for your own use.
Page Map |
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|---|---|
| Keyboard History | Mouse Types |
| Multimedia Keyboard | Mouse Buttons |
| Mouse History | Conclusion |
Keyboard:
History:
All modern keyboards derive their heritage from the typewriter, invented by Lathan Sholes in 1868. Though it could be argued that modern computer keyboards are actually derived from the teletype machine, introduced in the 1930s, which combined the keyboard technology of the tipewriter (considered as both an input and a printing device) with the transmission properties of the telegraph. The first computers, however, tended to use punched cards for their input which lead to the marriage of typewirters and punch cards in machines called keypunches. These were the basis of early adding machines and in 1931 IBM was selling over a million dollars worth of these machines annually.
As intimated above, early computer keyboards were adapted from both the punch card and teletype technologies, Indeed, in ed a punched card reader as its input and output device. In 1948, the Binac computer used an electromechanically controlled typewriter to both input data directly onto magnetic tape (for feeding the computer data) and to print results. The emerging electric typewriter further improved the technological marriage between the typewriter and the computer.
It wasn't until the late 1970s, with the widespread use of video display units (VDUs) that the link between the teletype machine as both an input and display/output system was broken. This lead to the first 'modern' keyboards, used exclusively as an input device. However, in terms of it's layout and the nature of the keys the modern computer keyboard is a direct descendant of those first manual typewriters of the nineteenth century. The design is intentionally inefficient, but has remained essentially unchanged mainly due to inertia: mostuly because of those people trained to type well with typewriters and then with keyboards.
True PC keyboards start wth the 83-key PC/XT keyboard whith its function key sited on the left hand side. This, however, used a system that was electronically incompatible with the subsequent generations of keyboards. The 84-key PC/AT keyboard which followed employed a large 5-pin DIN connector to link it with the PC and it can be considered the first 'modern' keyboard (the additional 84th key on this keyboard being the System Request
With the development of CDs and multimedia applications came the 101-key 'Enhanced' keyboard with its 12 function keys along the top to the keyboard long with additional navigation and control keys (which generally came with 6-pin mini-DIN 'PS/2' connectors. In Europe this became the 102-key 'Enhanced' keyboard with the addition of an additional accent key. From this point European keys all had an additional key (positioned immediately to the right of the left-hand shift key) as compared with US keyboards. The 101 and 102-key keyboards eventually gave way to the 104 and 105-key 'Windows' keyboar layouts with the addition of two 'windows' keys and a menu key. The latest addition in this line is the 107-key 'Enhanced' keyboard with the addition of power managent keys. The 104/105-key and 107-key keyboards are now considered to be the 'standard' keyboards. Though multimedia variants on this model do offer more keys and buttons to provide functions such as volume control, media player buttons, and various user-configurable shortcuts such as to email clients and web browsers.
The Multimedia Keyboard
The image on the left shows a multimedia keyboard with the main banks of keys labelled. Though these keyboards started with a round PS/2 connector, it is now far more usual to have an 4-pin USB connector, like the one shown below.
This coveres standard wired keyboards, but recent wireless advances mean that yo don't necessarily have to use a wired keyboard to communicate with your PC (or laptop).
Wireless keyboards either connect to an USB connection point via infrared or bluetooth or they can connect directly to bluetooth-enabled PCs or laptops. This does mean that the keyboard needs to be powered independently (usually with batteries). These may be rechargeable or they may be standard batteries. The one big drawback is that the keyboard will not work unless the batteries are charged.
The latest 'must have' in the world of keyboards is the 'virtual keyboard'. Here a laser is used to project the image of a keyboard onto the user's desktop. The same laser scans the image it's projecting to detect the uer's key-taps. It looks great and has the 'wow' factor, however, I'm not so certain that I'd want to use one as it's missing the tactile feedback of other keyboards. Indeed, this is an important consideration when thinking of keyboards. How stiff the keys are, how much travel they have and how much feedback you have that a key's actually been pressed. These are all very important considerations that will all affect how you use and enjoy your keyboard.
A further consideration when chosing a keyboard is the precise alignment of the keyboard: its pitch and (ie angle presented to the hands) and how high it lies off the table. These are all very important considerations as the keyboard will need to feel comfortable in use (after all you may be spending several hours using it).
Mouse:
History:
Unlike the keyboard, the mouse did not appear as a computer peripheral until the computer itself was quite mature in design. Indeed, the mouse was invented by Douglas Engelbart of the Stanford Research Institute in 1963. It was originally called a 'bug' though the name 'mouse' was soon coined for the device, due to the chort that emerged from the back of the device, suggesting the presence of a tail. This first mouse used two gear wheels set perpendicular to one another to detect motion and it wasn't until the early 1970s that Bill English (then at Xerox PARC) replaced the external wheels with a single ball housed within the mouse's body whose motion was detected using perpendicular wheels that made contact with the ball. This became the predominant model of mouse used with all personal computers during the 1980s and 1990s. The Xerox PARC group was also the group that settled on the modern technique of using both hands to type on a full-size keyboard and grabbing the mouse as needed. During the 1970s Xerox introduced mice that were included with its Xerox Star machine. Later, Apple Computer released the Apple Lisa which, under the influence of the Star also included a mouse as a pointing device. Neither machine was very succesful and it wasn't until the release of the Apple Macintosh in 1984 with its Graphical User Interface (GUI) that the mouse first saw widespread use. The Macintosh design was so influential that its success soon led many other vendors to include mice with their computer products and by the 1980s the combination of keyboard and mouse was the standard means of interacting with a computer.
Types of Mouse
The standard mechanical mouse with its physical internal 'ball' has already been described above. This kind of mouse suffers from several major problems. It needs a flat surface to work on, which also needs to have sufficient friction that the ball rolls smoothly on the surface. Being physical the ball can pick-up grime from the surface on which it's rolling and this grime is transferred to the rotating armatures that actually detect the motion of the mouse. This was one reason for the development of the mousemat, however even these become grimy over the months and due to the build-up of dirt the purely mechanical mouse can become difficult to use.
I remember coming across my first optical mouse (on a Silicon Graphics Workstation) this relied on a mousemat with a grid printed on it to locate the relative position of the mouse. Effectively this used an infrared LED and a four-quadrant infrared sensor to detect grid lines printed on a special metallic surface with infrared absorbing ink. Predictive algorithms in the CPU of the mouse calculated the speed and direction over the grid. However, as computing power became cheaper over the years it became possible to embed more powerful special-purpose image processing chips in the mouse. This advance enabled the mouse to detect relative motion on a wide variety of surfaces, translating the movement of the mouse into the movement of the pointer and eliminating the need for a special mouse pad. This advance paved the way for widespread adoption of optical mice. The latest generation of optical mice utilize an optoelectronic sensor to take successive pictures of the surface on which the mouse is operating. Most of these mice use LEDs to illuminate the surface that is being tracked (they are, however, often mislabelled as 'laser mice'). The mouse has an in-built image processor that detects changes between one image frame and the next one fed to it. Changes between one frame and the next are translated into movement on the X and Y axes and can be used to move the cursor on the screen.
The latest development in mouse technology is the laser mouse. These were developed by Logitech in 2004 and uses a small laser instead of an LED. Due to the nature of the laser this can increase the resolution of the image taken by the mouse up to 20-fold. However, lasers are very power-hungry and one of the prolems with laser mice is that they can 'dorp' connections on being moved from one location to another (this is an energy saving mechanism).
Both optical and mechanical mice have their followers and for corded mice the superiority of one kind over another is really 'much of a muchness'. However, if you have a cordless mouse then the power consumtion of a mechanical mouse is much less than that of an optical mouse. Though an optical mouse can be more sensitive and is less prone to the influence of dirt on its mechanisms.
Mouse Buttons
Apart from the physical mechianism used to detect the location of the mouse the only other major design feature of the mouse is the number of buttons. Typically this ranges from a single button to three buttons. Apple computer has typically used a single-button mouse whilst PCs running Windows have two-button mice. The various flavours of *NIX generally have three-button mice with the three buttons having specific functions. Indeed, with its UNIX underpinnings Mac OSX supports multi-button mice and even Apple, with their Mighty Mouse provided a four-button mouse.
Some mice have a scroll wheel in place of the second button, which can be used in rotational mode to scroll up and down web pages or documents but which can also be 'clicked' as if it were an additional mouse button.
Like keyboards mice now come in a variety of wired and wireless versions (with the most common wired form being the USB mouse). Wireless forms can either be bluetooth-based or they can be based on infrared communication with an USB base station (this is often a cradle where the mouse can be 'docked' to allow it to be charged).
Conclusion
The term 'keyboard and mouse' has almost become synonymous with the term 'computer' as they've both become essential ways of interacting with this machine. Though with the advent of the 'mousepad' (a pressure-sensitive pad used in palce of the mouse) there are some keyboards which now integrate the functions of the mouse into their structure. However, until voice and writing recognigion systems become better the combination of the keyboard and the mouse will be our main means of interacting with the computer for some time yet.
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