[_b8r0]

80% of what a beginner to IBM big iron would learn at first can be done on MVS 3.8.

It's more like the difference between SysV and Linux, or Windows NT and modern Windows. Major differences and lots of features in the newer stuff, but for first principles it'll do.

Like I said, if you want modern(ish) Z/OS, ADCD is your best bet.