If you want to have a truly parallel system, you cannot share resources between processes. If you need a lock, then that implies sharing of resources... Which implies limited scalability according to Amdahl&#x27;s law.<p>To achieve unlimited scalability, you need to make sure that no single data store is shared between all processes and that the amount of interprocess communication (on a per-process basis) doesn&#x27;t increase as you add more processes.<p>The more sharing you have, the less you can scale your system.