You are likely looking at this design from a modern system perspective. But the PDP-11 system that many of these designs were made upon had a minimum memory si

You are likely looking at this design from a modern system perspective. But the PDP-11 system that many of these designs were made upon had a minimum memory size of 4K bytes and with varying models that had different maximum memory sizes that are smaller than a single JPEG photo in today's world: PDP 11/45 max memory 256kbyte - PDP 11/70 max memory 4Mbyte. And this was the total memory for everything, the OS, and the users, and the system supported multiple users sharing the same machine at the same time. With those resource constraints, the design rules that determine good from poor are radically different than with one of today's systems with multiple Gb of RAM.