Caps Lock - History

History

The caps lock key is a modified version of the shift lock key that occupies the same position on the keyboards of mechanical typewriters. An early innovation in mechanical typewriters was the introduction of a second character on each typebar, thereby doubling the number of characters that could be typed, using the same number of keys. The second character was positioned above the first on the face of each typebar, and the shift key caused the entire type apparatus to move, physically shifting the positioning of the typebars relative to the ink ribbon. Just as in modern computer keyboards, the shifted position was used to produce capitals and secondary characters.

Because the shift key mechanism on a mechanical typewriter requires more force to operate and is usually operated by the little finger on the left hand, it was difficult to hold the shift down for more than two or three consecutive strokes, therefore the introduction of the caps lock key also helped out people with disabilities who could not hold down more than one key at a time. The shift lock key was introduced so the shift operation could be maintained indefinitely without continuous effort. It literally locked the shift mechanism, causing the upper character to be typed upon pressing any key.

The caps lock key on modern QWERTY keyboards differs from the shift lock key in that it capitalizes letters but does not affect other keys, such as numbers or punctuation. Some early computer keyboards, such as the Commodore 64, had a shift lock but no caps lock; others, such as the BBC Micro, had both, only one of which could be enabled at a time.

A version of caps lock that behaves like a traditional shift lock does exist on certain layouts such as the French AZERTY. Some operating systems and window managers allow caps lock to be used for a similar function. This behavior of the caps lock survives, however, in German and Austrian QWERTZ keyboards.

The keyboards of many early computer terminals, including the Teletype Model 33 ASR and Lear-Siegler ADM-3A, and early models of the IBM PC, positioned the Control key on the left of the keyboard, where caps lock resides on most modern keyboards. This layout was preserved for later workstation systems and is often associated with Unix workstations. Keyboards from Sun Microsystems came in two layouts; "Unix" and "PC-style", with the Unix layout having the traditional placing of the Control key and other keys. The keyboards produced for One Laptop Per Child computers also have the Control key in this location. Other vendors produce keyboards for different computer systems with this placement of the Control key, such as the Happy Hacking Keyboard. In a similar vein, the Google Cr-48 netbook replaces caps lock with a dedicated "Search" key.

Some users of keyboards with caps lock on the left remap the keys to exchange Control and caps lock, finding the traditional location more ergonomic for using programs benefiting from use of the Control key. Keyboard layout preferences specifically to address this need are available in some operating systems.