A shop I worked in ages ago had a mainframe on site supporting lots of batched transactions over the course of a 24 hour period, along with the daily operations

A shop I worked in ages ago had a mainframe on site supporting lots of batched transactions over the course of a 24 hour period, along with the daily operations for a 35 facility logistics company, spread throughout the southeastern United States. They had a staff of 8 mainframers that ran the entire operation. All of the PCs onsite (my area of responsibility) were basically 3270 terminal clients for z/OS. Sometime later, a connection on LinkedIn pointed out the following resources: https://www.openmainframeproject.org/ https://www.openmainframeproject.org/ https://github.com/openmainframeproject https://github.com/openmainframeproject https://github.com/openmainframeproject/cobol-programming-course https://github.com/openmainframeproject/cobol-programming-co... Also, mainframes are really good at high throughput transactional jobs. That's why you see them in banks, transportation, insurance, etc. Big Tech™ doesn't see it as "cool" and are too focused on the Next Big Thing™, so there's not a lot of attention there. Sometimes, boring just gets the job done.