[TUHS] Device special files

[Doug McIlroy]

> Why is it that umount(2) took the device special file name rather than the mount point directory name, anyway?

Symmetry. You unmount what you mount.

A competing model is that of links. Link makes an old file available
under a new name. But you unlink by the new name. Necessarily so,
because there may be many new names for one old file.

This is reminiscent of Don Norman's screed about the unnaturalness
of Unix. He didn't like strcpy because the arguments come in the
opposite order to those of cp. But stcpy is part of C, and in
C the destination of assignment comes before the source. But Norman
didn't rail at C. You pays your money and takes your choice.

Doug