The document discusses various consistency models including strict consistency, sequential consistency, causal consistency, pipelined random access memory consistency, processor consistency, and weak consistency. It focuses on explaining the sequential consistency model, which requires that all processes in the system see the memory operations in the same order, and allows different interleavings of read and write operations as long as this requirement is met. The document also discusses different strategies for implementing sequential consistency in distributed shared memory systems, including nonreplicated nonmigrating blocks, nonreplicated migrating blocks, replicated migrating blocks, and replicated nonmigrating blocks.