Process Address Space

The OS/2 memory allocation functions return a 32-bit pointer to the allocated memory object. While a 32-bit pointer is sufficient to address the entire 4 gigabyte global address space, applications can access only the first 512MB of linear memory, called the process address space. Of this 512MB process address space, a minimum of 64MB is reserved for shared memory regions, leaving 448MB. Of this 448MB, some will be used by the application itself and a small amount will be taken by operating system overhead. The remainder is available for allocation. The amount of memory that can actually be committed and used is, of course, determined by the physical memory and hard disk space available on the machine.

Keep in mind that the amount of memory that can be committed for actual use is limited by the amount of physical memory and free hard disk space that is available on the computer on which the application is executing.


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