Wednesday, December 1, 2010

keyboard history

A QWERTY keyboard on a laptop computer
QWERTY (pronounced /ˈkwɜrti/) is the most used modern-day keyboard layout. The QWERTY design is based on a layout created by Christopher Latham Sholes in 1873 for the Sholes and Glidden typewriter and sold to Remington in the same year, when it first appeared in typewriters. It became popular with the success of the Remington No. 2 and No. 3 and No. 389 of 1878, and remains in use on electronic keyboards due to the network effect of a standard layout and a belief that alternatives fail to provide very significant advantages.[1] The use and adoption of the QWERTY keyboard is often viewed as one of the most important case studies in open standards because of the widespread, collective adoption and use of the product, particularly in the United States.[2]

Differences from modern layout

Latham Sholes' 1878 QWERTY keyboard layout
The QWERTY layout depicted in Sholes' 1878 patent includes a few differences from the modern layout, most notably in the absence of the numerals 0 and 1, with each of the remaining numerals shifted one position to the left of their modern counterparts. The letter M is located at the end of the third row to the right of the letter L rather than on the fourth row to the right of the N, the letters C and X are reversed, and most punctuation marks are in different positions or are missing entirely.[8] 0 and 1 were omitted to simplify the design and reduce the manufacturing and maintenance costs; they were chosen specifically because they were "redundant" and could be recreated using other keys. Typists who learned on these machines learned the habit of using the uppercase letter I (or lowercase letter L) for the digit one, and the uppercase O for the zero.[9] The exclamation point, which shares a key with the numeral 1 on modern keyboards, could be reproduced by using a three-stroke combination of an apostrophe, a backspace, and a period. The 0 key was added and standardized in its modern position early in the history of the typewriter, but the 1 and exclamation point were left off some typewriter keyboards into the 1970s.[10]

Contemporary alternatives

There was no particular technological requirement for the QWERTY layout,[clarification needed] since at the time there were ways to make a typewriter without the "up-stroke" typebar mechanism that had required it to be devised. Not only were there rival machines with "down-stroke" and "frontstroke" positions that gave a visible printing point, the problem of typebar clashes could be circumvented completely: examples include Thomas Edison's 1872 electric print-wheel device which later became the basis for Teletype machines; Lucien Stephen Crandall's typewriter (the second to come onto the American market) whose type was arranged on a cylindrical sleeve; the Hammond typewriter of 1887 which used a semi-circular "type-shuttle" of hardened rubber (later light metal); and the Blickensderfer typewriter of 1893 which used a type wheel. The early Blickensderfer's "Ideal" keyboard was also non-QWERTY, instead having the sequence "DHIATENSOR" in the home row, these 10 letters being capable of composing 70% of the words in the English language.[6]

Properties

Alternating hands while typing is a desirable trait in a keyboard design, since while one hand is typing a letter, the other hand can get in position to type the next letter. Thus, a typist may fall into a steady rhythm and type quickly. However, when a string of letters is done with the same hand, the chances of stuttering are increased and a rhythm can be broken, thus decreasing speed and increasing errors and fatigue. In the QWERTY layout many more words can be spelled using only the left hand than the right hand. In fact, thousands of English words can be spelled using only the left hand, while only a couple of hundred words can be typed using only the right hand. In addition, most typing strokes are done with the left hand in the QWERTY layout. This is helpful for left-handed people but to the disadvantage of right-handed people.[11]

Computer keyboards

The standard QWERTY keyboard layout used in the US. Some countries, such as the UK and Canada, use a slightly different QWERTY (the @ and " are switched in the UK); see keyboard layout.
The first computer terminals such as the Teletype were typewriters that could produce and be controlled by various computer codes. These used the QWERTY layouts, and added keys such as escape (ESC) which had special meanings to computers. Later keyboards added function keys and arrow keys. Since the standardization of PC-compatible computers and Windows after the 1980s, most full-sized computer keyboards have followed this standard (see drawing at right). This layout has a separate numeric keypad for data entry at the right, 12 function keys across the top, and a cursor section to the right and center with keys for Insert, Delete, Home, End, Page Up, and Page Down with cursor arrows in an inverted-T shape.

Diacritical marks and international variants

Different computer operating systems have methods of support for input of different languages such as Chinese, Hebrew or Arabic. QWERTY is designed for English, a language without any diacritical marks. QWERTY keyboards meet issues when having to type an accent. Until recently, no norm was defined for a standard QWERTY keyboard layout allowing the typing of accented characters, apart from the US-International layout.
Depending on the operating system and sometimes the application program being used, there are many ways to generate Latin characters with accents.

UK-Extended Layout

Microsoft Windows XP SP2 and above provide the UK-Extended layout that behaves exactly the same as the standard UK layout for all the characters it can generate, but can additionally generate a number of diacritical marks, useful when working with text in other languages (including Welsh - a UK language). Not all combinations work on all keyboards.
  • acute accents (e.g. á) on a,e,i,o,u,w,y,A,E,I,O,U,W,Y are generated by pressing the AltGr key together with the letter, or AltGr and apostrophe, followed by the letter (see note below);
  • grave accents (e.g. è) on a,e,i,o,u,w,y,A,E,I,O,U,W,Y are generated by pressing the backquote (`) [which is now a dead key], then the letter;
  • circumflex (e.g. â) on a,e,i,o,u,w,y,A,E,I,O,U,W,Y is generated by AltGr and 6, followed by the letter;
  • trema (e.g. ö) on a,e,i,o,u,w,y,A,E,I,O,U,W,Y is generated by AltGr and 2, then the letter;
  • tilde (e.g. ã) on a,n,o,A,N,O is generated by AltGr and #, then the letter;
  • cedilla (e.g. ç) under c,C is generated by AltGr and the letter.
These combinations are designed to be easy to remember, as the circumflex accent (e.g. â) is similar to a caret (^), printed above the 6 key; the diaeresis (e.g. ö) is similar to the double-quote (") above 2 on the UK keyboard; the tilde (~) is printed on the same key as the #.
Like US-International, UK-Extended does not cater for many languages written with Latin characters, including Romanian and Turkish, or any using different character sets such as Greek and Russian.
Notes:
  • The AltGr and letter method used for acutes and cedillas does not work for applications which assign shortcut menu functions to these key combinations. For acute accents the AltGr and apostrophe method should be used.

Other keys and characters

International variants

Minor changes to the arrangement are made for other languages.

Alternatives to QWERTY

Turkish F keyboard.
The modern Dvorak Simplified Keyboard layout, the leading alternative keyboard layout to QWERTY.
Several alternatives to QWERTY have been developed over the years, claimed by their designers and users to be more efficient, intuitive and ergonomic. Nevertheless, none has seen widespread adoption, due partly to the sheer dominance of available keyboards and training.[12] Although studies have shown the superiority in typing speed afforded by alternative keyboard layouts[13] economists Stan Liebowitz and Stephen E Margolis have claimed that these studies are flawed and more rigorous studies are inconclusive as to whether they actually offer any real benefits.[1] The most widely used such alternative is the Dvorak Simplified Keyboard; another increasingly popular alternative is Colemak, which is based partly on QWERTY and is therefore easier for an existing QWERTY typist to learn while offering several optimisations.[14] Most modern computer operating systems support this and other alternative mappings with appropriate special mode settings, but few keyboards are manufactured with keys labeled according to this standard.


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