并行计算：
在并行计算中，多个处理器同时执行分配给它们的多个任务。并行系统中的内存可以是共享的，也可以是分布式的。并行计算提供并发性并节省时间和金钱。
分布式计算：
在分布式计算中，我们有多个自治计算机，在用户看来它们是单个系统。在分布式系统中，没有共享内存，计算机之间通过消息传递进行通信。在分布式计算中，单个任务被分配到不同的计算机上。
并行计算和分布式计算的区别：
| S.NO | Parallel Computing | Distributed Computing | |||
|---|---|---|---|---|---|
| 1. | Many operations are performed simultaneously | System components are located at different locations | |||
| 2. | Single computer is required | Uses multiple computers | |||
| 3. | Multiple processors perform multiple operations | Multiple computers perform multiple operations | |||
| 4. | It may have shared or distributed memory | It have only distributed memory | |||
| 5. | Processors communicate with each other through bus | Computer communicate with each other through message passing. | 6. | Improves the system performance | Improves system scalability, fault tolerance and resource sharing capabilities |