Abstract: Programs to be executed on a distributed computer system are instrumented to allow data sharing. The distributed computer system includes a plurality of workstations. Each workstation includes a processor, a memory having addresses, and an input/output interface connected to each other by a bus, the input/output interfaces connecting the workstations to each other by a network. A set of virtual addresses assigned to the memories are allocated to store a shared data structure as one or more blocks accessible by instructions of programs executing in any of the processors. The size of a particular allocated block can vary with the shared data structure. Each block includes an integer number of lines, and each line including a predetermined number of bytes. Prior to executing the programs, the programs are statically analyzed to locate instructions that access the shared data stored at target addresses of the lines of the one or more blocks.