transferring processes under csh

[Philip Budne]

While TOPS-20 (and TOPS-10) do have ATTACH/DETACH, they relate to
changing the terminal a "job" is attatched to.  While this would be
wonderful (process trees could be detatched on loss of carrier), it
would also be hard to implement in Un*x (As pointed out by Rick Ace).

	Strangely the gruesome S5 sxt kludge makes ATTACH/DETATCH
	easier, as it isolates interaction with the physical terminal.

	S.M. Bellovin described a similar implementation at the SF
	Usenix called the "Session TTY manager".

Hewever it is best to liken to problem of moving a process
from one csh to another to the ITS DISOWN/REOWN system calls.
Which allow you to alter the shape of a "job tree".  ITS has
ATTACH and DETACH functions as well.

The wonderful thing about the ITS job (process) interface is that
processes are manipulated via the file system, each process has a
unique name and thus you can manipulate any process without regard to
superior/inferior (parent/child) relationships.

	Phil Budne, Boston University