Virtual memory and virtual address space are two different things, but they are related and work together to allow a computer to run programs that are larger than the amount of physical memory (RAM) available on the system.
Virtual memory is a technology that allows a computer to use part of its hard drive (HDD) as if it were RAM. This allows the system to run multiple programs or processes at the same time, even if there is not enough physical memory available to run all of them simultaneously. When a program needs more memory than is available in RAM, the system can temporarily move some of the data from RAM to the hard drive, making space available in RAM for the new program. This process is transparent to the user and is managed by the operating system.
Virtual address space, on the other hand, is a concept in computer architecture that refers to the range of memory addresses that a program can access. The virtual address space of a program is the set of logical addresses that the program uses to reference memory. This means that the program sees a contiguous range of memory addresses that it can use, even though the physical memory of the system may be fragmented or not fully contiguous. The virtual address space is created by the compiler when the program is compiled, and it is stored in the program's binary code.
In summary, virtual memory allows a computer to use part of its hard drive as if it were RAM, while virtual address space is the range of memory addresses that a program can use to reference memory. These two concepts work together to allow a computer to run programs that are larger than the amount of physical memory available on the system.
