Editing Keyboard buffer

{{More citations needed|date=June 2023}}

A '''keyboard buffer''' is a section of [[computer]] [[computer storage|memory]] used to hold keystrokes before they are processed.<ref>{{Cite web |last=Rouse |first=Margaret |date=September 16, 2015 |title=Keyboard Buffer |url=https://www.techopedia.com/definition/7926/keyboard-buffer |access-date=June 21, 2023 |website=TECHNOPEDIA}}</ref>

[[Computer keyboard|Keyboard]] buffers have long been used in [[command line interface|command-line]] processing. As a user enters a command, they see it [[Echo (computing)|echoed]] on their [[computer display|terminal]] and can edit it before it is processed by the computer.

In [[time-sharing]] systems, the location of the buffer depends on whether communications is full-[[Duplex (telecommunications)|duplex]] or half-duplex. In full-duplex systems, keystrokes are transmitted one by one. As the main computer receives each keystroke, it ordinarily appends the character which it represents to the end of the keyboard buffer. The exception is [[control character]]s, such as "delete" or "backspace" which correct typing mistakes by deleting the character at the end of the buffer.

In half-duplex systems, keystrokes are echoed locally on a [[computer terminal]]. The user can see the command line on their terminal and edit it before it is transmitted to the main computer. Thus the buffer is local.

On some early [[home computer]]s, to minimize the necessary hardware, a [[CPU]] interrupt checked the keyboard's switches for key presses multiple times each second, and recorded the key presses in a keyboard buffer for the operating system or application software to read.

On some systems, if the user presses too many keys at once, the keyboard buffer overflows and will emit a beep from the computer's internal speaker.

== Other uses ==

The use of keyboard buffers is sometimes known from the user experience side as [[typeahead]].

==References==
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[[Category:Computer keyboards]]
[[Category:Computer memory]]