The PCS libraries have been developed over many years at several different establishments. Initially developed as part of the ADAM environment for instrument control at the Royal Observatories, notably ROE, the environment was adopted in 1986 by the Starlink project at the Rutherford Appleton Lab to support data analysis programs. Since then further developments have been made by ROE with substantial support and further developments from Starlink and additional support from AAO and JACH.