Shared data controlled by a plurality of users

Claim 1

In a data processing system which includes a plurality of users, each of which may require access to the same data in an addressed location of a data store for the purpose of processing the data accessed in accordance with a first program of instructions, apparatus associated with each of the users comprising: register means, including a first register means for storing the data accessed from the addressed location and, a second register means for storing data resulting from the processing of the data in said first register by the first program; and replacing means connected to the data store and said register means, including first and second gating means and comparing means, operative subsequent to the processing of the accessed data by the first program of instructions, for comparing by saId comparing means the data in the addressed location of the data store and the data from said first register means for producing alternate signals indicating inequality or equality, and for replacing the data in said first register means with the data from the addressed location in the data store by said first gating means upon inequality, or replacing the data in the addressed location of the data store with the processed data from said second register means by said second gating means upon equality.