REQUIREMENTS IMPOSED BY SOME KINDS OF USER LEVEL PROGRAMS

In addition to the fundamental ideas mentioned in Chapter 4, we were guided by the requirements of various special kinds of user level programs which we felt the system should support. These special programs supply services which must eventually be provided. (One alternative would have been to construct the system so that it directly provided these services. In that case, the portions of system code which provided these services would probably have made demands on the remainder of the system which are similar to the requirements described below.)