jr@amanue.UUCP (Jim Rosenberg) (03/05/89)
In article <7198@killer.DALLAS.TX.US> wnp@killer.Dallas.TX.US (Wolf Paul) writes: >3. Is there a way of completely circumventing the user agent, and to > start the machine up with, say, 4 windows, all running getty, so > one can log in four times, a la PC6300 or other 286 Unix versions? **YES**! This is a somewhat controversial topic up here, so be prepared to get some divergent opinions. As long as you are careful to avoid certain gotchas the screaming prohibitions advertised at the beginning of /etc/inittab not to edit it can be quite happily thrown in /dev/null. You *can* edit inittab and create multiple gettys on /dev/window. I haven't used the User Agent in so long I'm not sure I remember how; I normally run with 6 gettys. Here are the relevant lines from my inittab: vid:2:respawn:/etc/getty window 9600 v2:2:respawn:/etc/getty window 9600 v3:2:respawn:/etc/getty window 9600 v4:2:respawn:/etc/getty window 9600 v5:2:respawn:/etc/getty window 9600 v6:2:respawn:/etc/getty window 9600 :v7:2:respawn:/etc/getty window 9600 This gives me my 6 gettys and 7 if I turn on v7, which I don't often do. You *WILL* encounter trouble if you tamper with inittab willy-nilly, but I think the following lists the gotchas: (1) For a line already in inittab, don't delete it and make sure either ' ' or dealing with inittab are a disgrace and behave *very* badly in the face of unexpected formats. The prohibition against editing inittab is mostly a CYA maneuver to cover for poorly written programs. (2) Make sure the new lines you create have either ' ' or ':' in the first column and that the first field is unique. (3) ***DO NOT*** put in a getty for an explicit /dev/w?, e.g. /dev/w7. This doesn't work. Each getty should use the *same* device, /dev/window. An open on an unused /dev/w? will fail; the driver expects such a device to be opened by an open on /dev/window. /dev/window is sort of like /dev/tty for window; when you open /dev/window it allocates a new window and then opens that device. Other than this so long as you adhere to the published format for inittab you should be all right. Now for the bad news. Almost all of UNIX works just fine with multiple gettys, but there are a few library routines that break. The main culprit seems to be getlogin(3C). Any utility which depends on this routine will produce flaky results. If you are addicted to that cute envelope icon to inform you of new mail you may be unhappy with multiple gettys. There are a few other programs that do strange things, but personally I use multiple gettys every day & have never been sorry. Note that you will consume a window for an enabled getty even if you don't have anyone logged in on that window. Since UA is rather piggy in how many windows it consumes, you may have to restrict yourself to 3 or 4 gettys if you want to run UA in one of them. At one time there were allegations that multiple gettys can cause all kinds of dire consequences, but I was never convinced there was a reason not to enjoy them. Perhaps one of you multiple-getty flamers can summarize the ojbections. -- Jim Rosenberg CIS: 71515,124 decvax!idis! \ WELL: jer allegra! ---- pitt!amanue!jr BIX: jrosenberg uunet!cmcl2!cadre! /
ditto@cbmvax.UUCP (Michael "Ford" Ditto) (03/06/89)
In article <449@amanue.UUCP> jr@amanue.UUCP (Jim Rosenberg) writes: [ about adding window gettys to /etc/inittab ] >(2) Make sure the new lines you create have either ' ' or ':' in the first >column and that the first field is unique. I think I would advise just the opposite. The ' ' or ':' convention relies on undocumented behavior by /etc/init, breaks some programs which parse inittab, and makes those lines subject to being geferked with by programs which run setgetty. The ONLY reason to use the ' '/':' convention is so that uucico or cu can turn off that getty when it dials out on that line (and hopefully you don't do uucp through a window!). The correct way to disable a getty is to change its "respawn" field to "off". -- -=] Ford [=- "The number of Unix installations (In Real Life: Mike Ditto) has grown to 10, with more expected." ford@kenobi.cts.com - The Unix Programmer's Manual, ...!sdcsvax!crash!kenobi!ford 2nd Edition, June, 1972. ditto@cbmvax.commodore.com
wnp@killer.DALLAS.TX.US (Wolf Paul) (03/07/89)
In article <6144@cbmvax.UUCP> ditto@cbmvax.UUCP (Michael "Ford" Ditto) writes: > ... . The ONLY reason to use the ' '/':' convention is so >that uucico or cu can turn off that getty when it dials out on that line >(and hopefully you don't do uucp through a window!). ... ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Well, maybe there are some folks out there who like speaking g-protocol to their 3b1 ... -- Wolf N. Paul * 3387 Sam Rayburn Run * Carrollton TX 75007 * (214) 306-9101 UUCP: killer!wnp ESL: 62832882 DOMAIN: wnp@killer.dallas.tx.us TLX: 910-380-0585 EES PLANO UD