The technology stack was exponentially smaller and more stable. For me, everything I needed to know were in three 300 page books. One was in JCL. The other two

The technology stack was exponentially smaller and more stable. For me, everything I needed to know were in three 300 page books. One was in JCL. The other two were about the SAS modules that were installed on the mainframe, the base SAS procedures and the book on how to write macros. The mainframe predated the internet and was limited in how many characters you could input per line. And you inputted one line at a time. But with it I could conduct transactions around the world in real-time as long as the transaction was limited to alphanumeric with very few special characters.