What is a MMU?

MMU is an acronym for Memory Management Unit. It is present in most modern computers providing hardware protection and redirection of memory access. This has been used extensively in the Commodore debugging program, Enforcer, that tracks illegal accesses to memory. The MMU is used in many cases to fool an application into believing that a designated space on a hard drive is real memory, hence the name Virtual Memory. Windows uses virtual memory extensively to run many applications by default (although this can be disabled). Whilst the thought of 4Gb virtual memory in your computer may sound appealing, it has the disadvantage of being slower than real memory. It also relies on the speed of your hard drive and the amount of space free and should only be considered as a temporary alternative to buying real memory. As standard the A1200 does not come with a MMU, but can add a 68030 card with one fitted. Dave Haynie, one of the original creators of the Amiga commented that a MMU had been left out of the original Amiga design as it meant task-switching became more "hairy", requiring a greater amount of memory. However, in these times of increasing clock speed and memory sizes the MMU should be considered an essential part of any Amiga setup. It is especially useful for 3D rendering and some games use this to increase their performance.

BACK