Welcome to the Z OS dev blog.
Most of Z OS will developed in a language that is higher-level than C. That means that our toolchain, as well as our assumptions will be very different from most OSes. The emphasis is on correctness, separation of semantics & implementation, speed, and functionality. As a rule, we should only support one way of doing a particular thing (eg. sound) at a time. That will keep the number of configurations we support low, and provide a better user experience.
When we get beyond the proof of concept stage, we will add a POSIX environment so that we have access to the vast wealth of Open Source software that exists for UNIX-like OSes. Then, to encourage Windows users, we will integrate a wine subsystem to provide a place to run win32/64 apps.
We are going to lean heavily on the work of others, particularly in the area of drivers, and end-user software.
Initial targets will be x86 and ARM.