Devices are memory-mapped without going through many nested protocols (USB, PCIe, etc). What drivers do is completely transparent. Library calls are a simple

Devices are memory-mapped without going through many nested protocols (USB, PCIe, etc). What drivers do is completely transparent. Library calls are a simple subroutine which jumps into the real details, without a privilege barrier. Much of the accessibility of the architecture is that it's a single address space, with no MMU interference to speak of (later models had MMUs, but where only used for a few enhancements here & there at best). Besides, 680x0 code is much more pleasant to deal with than x86. But that's the case for pretty much any non-x86 ISA. ;-)