<suspend> command in csh; why not for the login shell?

[Danny Glasser]

<LE>

(PLEASE respond to this by mail; I don't read this newsgroup regularly.)

The csh "suspend" command allows the user to suspend a sub-shell of the
login shell, as if the user had typed ctrl-Z to the shell.  However, if
the user tries to invoke the "suspend" command in the login shell, the
following message is returned:

	% suspend
	Can't suspend a login shell (yet).
	%

It would be very useful to be able to "suspend" one's login shell (and
any processes running under it) and then access this shell later on.
Suspending a login shell would be an alternative to "logout", and when
the user logged back in again, he/she would have the option of creating
a new login shell or accessing a suspended login shell.  Note that
TOPS-20 has a similar feature, accessed with the commands "DETACH" and
"ATTACH".

Having said all this, I pose the following questions:  Why hasn't this
been done?  (The word "yet" in the failure message indicates that it
was or is being planned.)  Has anyone tried to implement such a
feature, and if so, has this person been successful, or found a
compelling reason for it being impossible or highly impractical?  Can
anyone provide me with pointers to people, software, articles or other
information which I could consult if I were interested in attempting to
implement this feature?

Once again, please respond by mail, not by posting to net.unix-wizards.
If you are interested in seeing the responses I receive, send me mail;
I will reply with the responses, or post if there is sufficient demand.

Thank you very much.

Danny Glasser
Yale University Department of Computer Science

...{decvax,seismo}!yale!dglasser
Glasser-Daniel at YALE.ARPA (YALE.EDU)
dglasser at YALE-CHEOPS.ARPA
GLADANS at YALEVMX.BITNET

Phone: (203) 432-7227