Padding

Some older terminals require additional time to perform certain functions, such as clearing the screen. With these terminals, if the application sent a "clear screen" sequence immediately followed by other characters, some characters may be lost or ignored by the terminal.

Most terminals have sufficient buffering to prevent data overrun. However, if data overrun is possible, an XON/XOFF protocol can be invoked to temporarily suspend output to the terminal. This protocol takes place between the terminal and the host operating system and does not affect the application program.

When examining termcap entries for older terminals, some sequences may be encountered that begin with some digits. For example:

:cl=20\E*:

The "20" at the front of the entry means "wait 20 milliseconds after sending the sequence" and is not actually sent to the terminal. See a termcap reference manual for a more complete description of padding.