# Tops-20

So what is a TOPS-20? It's an OS that DEC (Digital Equipment Corporation) released in the mid-70s. My College had one around that time. The first real CS class at the time was in Pascal, which ran under TOPS-20. To be honest, I never saw the hardware it ran on, only the terminals we type code into.

One had to wait for their turn on a terminal, so it forced them to pre-write and prepare the code before entering it as a program. Sometimes I believe it helped to form good discipline and think of the problem before writing the program.

The image above is a DEC System20 that TOPS-20 could run on

[Wikipedia's entry for TOPS-20](https://en.wikipedia.org/wiki/DECSYSTEM-20)