It does mean high level language, and in this context it's trying to illustrate that Oberon is used to write the OS and drivers, despite having GC, a repl, obje

It does mean high level language, and in this context it's trying to illustrate that Oberon is used to write the OS and drivers, despite having GC, a repl, objects and other high-level constructs (compare with C for example). The general assumption is that if you don't have exact control over memory and threading, you can't write an OS.