1. We should have some ways of connecting programs like garden hose--screw in another segment when it becomes when it becomes necessary to massage data in another way. This is the way of IO also.

Point 1 is the interesting one. It provides the historical background for Doug's encouragement of the Unix pipe notation. The linked paper gives appropriate credit; in interviews, Doug has been explicit in saying that he very nearly exercised managerial control to get pipes installed.