1. A system for allocating shared memory of differing properties to shared data objects, comprising: a processor; said shared memory; wherein said processor is configured to cause: a hybrid stack creator to create, in said shared memory, a hybrid stack data structure having a first portion and a second portion having a property less favorable than a property of said first portion of said shared memory; and a data object allocator associated with said hybrid stack creator to allocate storage for shared data object in said first portion if said first portion has a sufficient remaining capacity to contain said shared data object and alternatively allocate storage for said shared data object in said second portion if said first portion has an insufficient remaining capacity to contain said shared data object; wherein: said shared data objects are allocated and deallocated only during a sequential region of program execution; and said shared data objects are accessed only during a parallel region of said program execution.