UNIX is a kernel implementation.

Concepts

• file descriptor

• process

• signal

• system call

External

• Wikipedia page about UNIX.

• Standardizing UNIX, an article by David Chisnall.

• The first in the series, Neil Brown's 2010-10-27 article Ghosts of Unix Past: a historical search for design patterns introduces the concepts of file descriptors and the single, hierarchical ?namespace.

  Next, Neil Brown's 2010-11-04 article Ghosts of Unix past, part 2: Conflated designs discusses issues with conflated designs such as the mount command (a problem we have partly solved / solved differently with our translator approach and the virtual file system), and the plethora of flags that can be passed to the open system call.

  In Neil Brown's 2010-11-16 article Ghosts of Unix past, part 3: Unfixable designs, he deals with unfixable designs, such as UNIX signals and the UNIX permission model (which is clearly inferior to a capability-based system).

• UNIX File Permissions (2004) by Richard Kettlewell. (open issue documentation)