Optimal Dynamic Use of Memory for PL/1 Object Programs in a Real Memory Environment
K. Dos, H-P. Otto · The Computer Journal · 1972
Some basic considerations on dynamic memory handling are made and a method is described which will improve the efficiency of dynamic memory allocations of PL/1 compiled object programs on 360-type machines. Its main objective is the special treatment of storage items with proper runtime stack behaviour by a runtime stack memory retailing subsystem using multiple, not necessarily adjacent memory extents with an almost as high average allocation speed as when using a single extent. This is achieved by the preference of a ‘current stack extent’ which requires overhead only upon over- or underflow. The other storage items are handled by a non-runtime stack memory retailing subsystem with the main goal of keeping memory scattering as low as possible. A memory wholesaling subsystem interfaces the operating system and provides memory for both the retailing subsystems.