- In computing, virtual memory is a memory managment technique that is implemented using both hardware and software . it maps memory addresses used by a program, called virtual memory, into phsical addresses in computer memory . main storage as seen by a process or task appears as a contiguous addressspace or collection contiguous segments . the operation system manages virtual address spaces and the assignment of real memory to virtual memory . address translation hardware in the CPU, often referred to as a memory management unit or MMU, automatically translate virtual addresses to physical addresses . software within the operating system may extend these capabilities to provide a virtual address space that can exceed the capacity of real memory and thus reference more memory than is physically present in the computer .
- the primary benefits of virtual memory include freeing applications from having to manage a shared memory space, increased security due to memory isolation, and being able to conceptually use more memory than might be physically available, using the technique of paging .
Flash Memory
- Flash memory is an electronic non-volatile computer storage medium that can be electrically erased and reprogrammed.
- introduced by toshiba in 1984, flash memory was developed from EEPROM (electrically erasable programmable read-only memory) . there are two main types of flash memory, which are named after the NAND and NOR logic gates . the individul flash memory cells exhibit internal characteristics similar to those of the corresponding gates .
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