martin@suna8.cs.uiuc.edu (02/04/90)
Hello all,
Currently I am working on a Face-to-Face/Computer- Mediated
communication experiment for another's dissertation. It involves
four people solving an inductive-learning problem with the
communication either by talking, or typing to each other on
different terminals.
I'm using sessions in a token-ring environment to implement the
computer-mediated part of the experiment; They are arranged so each
session will only send/receive information in one direction, for
simplicity's sake. My problem is that if I send messages very quickly,
the communication hangs on all four stations. The messages can be a
single character, but the mass of messages will still cause the
communications to halt. I have played with send/receive timeouts
in many different configurations, to no avail. I have even made
my program ack messages back, and hang on a send until an ack message
has been received, but the problem goes away. This suggests to me
that it may not be a timeout problem at all, which baffles me.
Please, if you have had experience with this before, and have an
answer or work-around, please, PLEASE, let me know! This program must
work soon for this lady to collect data in time for her dissertation.
Thanks in advance,
- Rocco Martinmeyer@sunb8.cs.uiuc.edu (02/07/90)
NETbios on a token-ring system is very flaky to program for, I agree. I had a similar 'mysterious' problem where a host program sent/received various types & sizes of messages to a number of client programs via sessions, with timer messages sent via datagram. The host program would randomly hang upon receipt of one type of message, often working perfectly for 5-10 minutes before hanging.ng. This message is neither the smallest nor largest message, so no buffer overflow problems. The solution - I implemented this specific message in datagram, an now it works perfectly. I'm not sure if you're doing this already, or not - but you may want to try posting one or more receives ahead of time. I generally do this as a rule - it tends to avoid blocking and improve throughput. (It doesn't work well under Windows/386 - any program using posted netbios commands will receive a "Not enough NCBs" error returned from the post command.) I have generally excellent success otherwise. _____ Don Meyer internet: dlmeyer@uiuc.edu (sunb8.cs.uiuc.edu) quote du jour: "If, indeed, there exists Artificial Intelligence, then there must also exist Artificial Stupidity" - ???