For an individual, yes - the barrier to entry is high. But I don't really see any way to change that, due to the very nature of mainframes: systems of complex a

For an individual, yes - the barrier to entry is high. But I don't really see any way to change that, due to the very nature of mainframes: systems of complex and highly tuned special purpose submodules. This is the first thing you'll notice when digging through the literature, lots of brand new non-standardized acronyms for purpose-built subsystems. While a lot of it certainly has the taste of needless market segmentation, there is a lot of unique stuff that is genuinely scarce. Yes, you can get a second hand mainframe at a bargain price - but your really don't want to unless it is part of a much larger tax advantaged living museum project. There are emulators though, Hercules and zPDT. My interests led me more to the Power architecture, which is weird enough to hold my interest - while still being practical at the individual scale. For example, the z15 comes with the NXU compression accelerator - the p9 has a similar (same?) NX coprocessor. You'll also find market segmentation here, and IBM would do well to knock it off with the weird PowerVM/NV/Opal/ePAR/LPAR stuff. Their performance monitoring and scheduling stuff is really awesome, and it is unfortunate that they use it to segment product offerings. It isn't as ugly as Intel's ECC games, but it still isn't a good look.