Output padding

In computing, output padding is the insertion of non-printing characters into the device output stream to allow for a preceding control operation to take effect.

Output padding was necessary on many printing devices, notably Teletype and other mechanical terminals, after the issuance of a carriage return.^[1] Without the padding, following characters might print in the middle of the output line.

Output padding was also necessary on many display terminals after cursor positioning, scrolling, and other commands.^[2][3]

Typically the null character was used; the delete character was occasionally used. The number of padding characters depended on the particular device, but also sometimes on the horizontal position of the printing carriage.