Chapter 3. Evolution of Software Technology
Virtual Memory and 64-Bit Architecture
The concept of virtual memory, introduced in the 1960s, eases software development by freeing the programmer from some aspects of memory management. Further developed through the 1970s, on minicomputer and mainframe operating systems, including UNIX, it is now standard practice even on desktop operating systems such as Windows.
In the absence of virtual memory, the size of any object (data or code) manipulated by program was limited to being no greater than the amount of free memory, set by the amount of physical memory less the amount of memory used by the OS and services such as runtime libraries. To handle objects bigger than available memory, programmers ...