[comp.protocols.appletalk] NSCA Telnet 2.3 bugs

wilson@csli.Stanford.EDU (Nathan Wilson) (10/04/89)

Speaking of NSCA bugs, I've run into a couple bugs in version 2.3.
Local Machine:
	IIcx, 8meg RAM, 80meg Quantum HD, Radius TPD, System 6.0.3,
	Multifinder, Assorted INITs

Network Environment:
	AppleTalk with 4 similar systems, LaserWriter IINTX, and
	Kinetics Fastpath 3 to Ethernet
	Ethernet has the KFPS 3, 4 Sun 2's and a DecStation 3100
	One of the Sun 2's is running CAP and SLIP

*** Mac/Sun/Name Service Bug: ***
The first bug is that when the machine at the other end of the
SLIP connection is down, I can't make *new* telnet or ftp connections.
I've isolated this to a problem with name service.  The file
server is doing name service using ypserv -i and the resolv.conf
points to a machine on the other side of the SLIP connection.
What seems to happen is that Telnet asks for some name resolution,
the sun spawns a new ypserv -i process and never gets a response,
Telnet hangs with the window to the machine open but no login
prompt ever appears.  The only fix I've found is to kill all the
ypserv processes on the file server and to restart using ypserv
without the -i flag.  Does anybody have an explanation for this?
What is Telnet asking for?

*** Window Size/vt100/tset Bug: ***
The senario:
	1) running NCSA Telnet 2.3 with vlines set to 65
	2) log into a local machine
	3) log into a remote machine
	4) on the remote machine (a vax) the .login asks for the
		terminal type using the command:

ts -Q -n -r -m switch:\?$defterm -m network:\?$defterm \?$term

	5) reply vt100 (expecting to use the command: stty rows 65 to
		make everybody happy).
		
The cursor now jumps up to the 24(?)th without scrolling, and from
now on NCSA Telnet acts like I have a 24 line terminal.  Worse than
that lines that scroll off the top don't get saved and if some program
on the host machine tries to use the lower lines it causes a system
error in Telnet.  The exact actions that just did this were the above
followed by:

	6) logout
	7) more bnf.tex
	8) Mac freezes.  Interrupt button doesn't work.  Have to do hard
		reset

Workaround:
	Do 1-4 above.
	5) reply dumb
	6) set term=vt100
	7) stty rows 65

and everything works.

*** Scrolling Bug: ***
Running NSCA Telnet 2.3 with vlines=65 and scrollback=325 fill up
the entire scrollback.  I just did this with a little C program that
prints the numbers from 0 to 399 on separate lines.  Now take the
scrollbar thumb and drag it all the way to the top.  Note that when
you let go it jumps down a little ways.  Now drag the thumb to the
bottom.  Now back to the top.  Note it doesn't jump this time.  Now
drag back to the bottom and back to the top.  The *bottom* line,
ie the current prompt, now appears as the oldest line.  Do an other
bottom/top pair and another the line with 399 appears at the top,
etc.  Sounds like pointer math problems.

*** Intermittent Redraw Bug: ***
Using the system so far described, I often run gnuemacs and have
several other Mac programs running like MPW, and Allegro Common Lisp.
Every once and while when a redraw is forced in Telnet by switching
back into it, I get the wrong stuff written on the screen.  Telling
gnuemacs to redraw itself usually fixes this but occasionally Telnet
will go down in flames.  This is particularly annoying because ACL
doesn't like it when I enter the debugger.  See posting in
mac.sys.programmer.  Unfortunately, I can't reproduce this one
reliably, yet.

*** Praise for Telnet: ***
Even given the above bugs, some of which I consider to be quite
serious, I must praise the folks at NCSA for a wonderful product.
All the Mac folk here use it on a daily basis with little or no
problems.

	Nathan Wilson
	Teleos Research
	nathan%teleos.com@ai.sri.com