Hello World on z/OS
The mainframe infrastructure is both the core feature and showstopper bug of the platform.  On the plus side, it has empowered countless core business applications to scale years, even decades, beyond their original development lifecycle.  On the negative side, it has created a stagnant cult of mainframe “priests” who oversee a platform that most businesses would rather get rid of, if they could only figure out how.<p>My startup was acquired by BMC software, one of the largest third party providers of mainframe software, and I also worked for EMC for a time early in my career, so I spent a lot of time hanging around the mainframe space.  Two quick anecdotes:<p>- working on a giant data center move for a big bank, there was a break room filled on a Saturday with operations people from the “open systems” (non-mainframe) and mainframe teams.  I was struck by the contrast: the Unix&#x2F;windows operations folks were tattooed, pierced, jeans and t-shirts, late 20s.  The mainframe folks were short hair, polos and jeans, mid-50s.  The two groups self segregated into clusters on opposite ends of the room, not speaking to each other.<p>- at a BMC leadership offsite, I found myself st the dinner table with a couple of mainframe engineering and product directors.  After a few drinks, we got on the subject of why more tech companies weren’t using mainframes.  “They’re so reliable! Why wouldn’t you just go out and rent one from IBM, and then you don’t have to worry about uptime or stability?”.  I explained that the fashion had become to build the reliability into the application and assume that the hardware was not reliable.  This confused them.  “That sounds like a huge pain in the ass, why would you bother dealing with that?” So I explained that the cost per compute cycle was so much cheaper that it made it worth it, plus open source, etc etc<p>One of them kept pressing: “but Facebook could just take all the engineers they’re devoting to building reliable infrastructure and shift those people to writing customer facing code!”<p>The other director stopped him and said, “don’t you see?  They’ve already done it.  There’s no reason for them to go back now.  People have figured out that they don’t need mainframes to get mainframe reliability”.  The other director just kept shaking his head and we moved to other subjects.<p>This conversation happened in 2014.