Program execution models

"An evolving system increases its complexity unless work is done to reduce it."                                                                                                                    

- Meir Lehman

In the early 1960s, before multitasking was even a thing, programs written for computers were limited to a sequential execution model, where they were able to run instructions one after the other in chronological order. This was mainly due to limitations in how many instructions the hardware could process during that time. As we shifted from vacuum tubes to transistors, then to integrated chips, the modern day computer opened up possibilities to support multiple points of execution in programs. Gone are the days of sequential programming model where computers had to wait for an instruction to finish before executing the next one. Today, it's more common for computers to be able to do more than one thing at a time and do it correctly.

The modern day computer models...