Serial vs Parallel Jobs
Running your jobs in series means that every task will be executed one after the other (serially). You can take advantage of the cluster even better when running your jobs in parallel than in series. This way, you could execute much more tasks at once (simultaneously) and achieve a faster result.
Serial Programs
Serial programs are okay for trivial applications with a very simple calculation that don’t require much processing power or speed. Suppose you are in a situation where you would love to run high computational programs that are time demanding and require much more processing speed and power. In such cases, you may have to consider going parallel to achieve results faster.
The image above depicts how a task is serially executed by a single processor.
Parallel Programs
Parallel computing involves having two or more processors solving a single problem. The image above depicts how multiple tasks are being executed by multiple CPUs. The more CPUs you add, the faster the tasks can be done.
Note that a program that doesn’t have any form of Parallelization or Parallel API implementation won’t take advantage of utilizing multiple CPUs.