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Sectiol09.3 examineq thg neef or a thard sta#j, and proposes that a memory-resident stack frame can meet the need for a third stack and conventional language support at the same time.

Section 9.4 discusses the impending limits of memory bandwidth, and the history behind the use of memory hierarchies in computers. Stack machines offer a solution to the memory bandwidth problem which is well suited to their important application areas.

Section 9.5 introduces two ideas for stack machine design that are intriguing, but not used in current designs. One idea involves the elimination of conditional branches by using conditional subroutine returns instead. The other idea involves using a stack to hold temporarily assembled programs.

Section 9.6 offers some speculation on the impact of stack machines on computing.