Keyboard buffer
Encyclopedia
A keyboard buffer is a section of computer
memory
used to hold keystrokes before they are processed.
Keyboard
buffers have long been used in command-line processing. As a user enters a command, they see it echoed
on their 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
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 his terminal and edit it before it is transmitted to the main computer. Thus the buffer is local.
On some systems, by pressing too many keys at once, the keyboard buffer overflows and will emit a beep from the computer's internal speaker.
Computer
A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...
memory
Computer storage
Computer data storage, often called storage or memory, refers to computer components and recording media that retain digital data. Data storage is one of the core functions and fundamental components of computers....
used to hold keystrokes before they are processed.
Keyboard
Computer keyboard
In computing, a keyboard is a typewriter-style keyboard, which uses an arrangement of buttons or keys, to act as mechanical levers or electronic switches...
buffers have long been used in command-line processing. As a user enters a command, they see it echoed
Echo (computing)
In computing, echo is a command in DOS, OS/2, Microsoft Windows, Singularity, Unix and Unix-like operating systems that places a string on the computer terminal...
on their terminal
Computer display
A monitor or display is an electronic visual display for computers. The monitor comprises the display device, circuitry, and an enclosure...
and can edit it before it is processed by the computer.
In time-sharing
Time-sharing
Time-sharing is the sharing of a computing resource among many users by means of multiprogramming and multi-tasking. Its introduction in the 1960s, and emergence as the prominent model of computing in the 1970s, represents a major technological shift in the history of computing.By allowing a large...
systems, the location of the buffer depends on whether communications is full-duplex
Duplex (telecommunications)
A duplex communication system is a system composed of two connected parties or devices that can communicate with one another in both directions. The term multiplexing is used when describing communication between more than two parties or devices....
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
Control character
In computing and telecommunication, a control character or non-printing character is a code point in a character set, that does not in itself represent a written symbol.It is in-band signaling in the context of character encoding....
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
Computer terminal
A computer terminal is an electronic or electromechanical hardware device that is used for entering data into, and displaying data from, a computer or a computing system...
. The user can see the command line on his terminal and edit it before it is transmitted to the main computer. Thus the buffer is local.
On some systems, by pressing too many keys at once, the keyboard buffer overflows and will emit a beep from the computer's internal speaker.