Of course they all inherited this design from Unix. As far as Microsoft is concerned, Windows and MSDOS inherited this design from XENIX, which was Microsoft's

Of course they all inherited this design from Unix. As far as Microsoft is concerned, Windows and MSDOS inherited this design from XENIX, which was Microsoft's clone of V7 UNIX. That XENIX was later sold to the Santa Cruz Operation, then later again SCO XENIX was renamed to SCO UNIX. It's fascinating to wonder how different the computing world would be today if Microsoft had used their XENIX as the underlying base for Windows, instead of the way they did do it. Linux would probably have never got off the ground, and remained a curiosity like the MINIX it was based upon initially. And Microsoft would completely own the UNIX world. Thank God they didn't.