 The ARM did not, for example, have an integral memory management unit, as this function was being provided by the MEMC support chip and Acorn did not have the resources to develop one.Apple and Acorn began to collaborate on developing the ARM, and it was decided that this would be best achieved by a separate company.The bulk of the Advanced Research and Development section of Acorn that had developed the ARM CPU formed the basis of ARM Ltd. when that company was spun off in November 1990.