A keyboard buffer is a section of computer memory used to hold keystrokes before they are processed.
In time-sharing systems, the location of the buffer depends on whether communications is full-duplex or half-duplex.
As the main computer receives each keystroke, it ordinarily appends the character which it represents to the end of the keyboard buffer.
On some early home computers, 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.