A virtual storage data processing system having an address translation unit shared by a plurality of processors, located in a memory control unit connected to a main memory is disclosed. One of the plurality of processors is a job processor which accesses the main memory with a virtual address to execute an instruction and includes a cache memory which is accessed with a virtual address. One of the plurality of processors is a file processor which accesses the main memory with a virtual address to transfer data between the main memory and an external memory. The cache memory receives the virtual address when the file processor writes to the main memory and if it contains a data block corresponding to the virtual address, it invalidates the corresponding data block. The address translation unit translates the address differently for the access from the file processor and the accesses from other processors.