Some areas of memory are permanently allocated or reserved for special purposes eg BIOS, Booting up, Video display, etc... but there will be an area of memory which can be allocated to other tasks as required. A memory map will show what areas of memory are allocated to what tasks...

The partitioning of memory may allow a number of different processes to be undertaken at the same time.

The operating system must make sure that..

• each task has enough memory to be executed.
• one task does not need an area of memory allocated to another task...if one task interferes with another it could crash the computer.
• the area of memory is released when the task is completed so that it can be allocated to another task.

Virtual memory techniques may be used where the memory required by a task is divided into pages. These pages can be swapped into memory when needed or on to hard disc when not required. (This makes the task think it is using more memory than it actually is!). The OS will need to keep very careful track of the pages and where they are stored!!

A buffer is an area of memory set aside for storing temporary data. Buffers are widely used for input and output data.