PCBoard was an MS-DOS BBS software package first created by the Clark Development Corporation, first introduced in 1983.
Clark Development pioneered the FILE_ID.DIZ format as well as a powerful scripting language (PPL) which supported modifications called PPEs (PCBoard Programming Executable).
The last full release of PCBoard by Clark Development was version 15.3 in September of 1996. The company went bankrupt in the late 1990s.