thomas@trane.UUCP (Thomas Driemeyer) (12/18/90)
I connected a digitizer tablet (looks like a mouse to the system) to ttyb of a Sun 3/60 running SunOS 4.0, i_popped the stream naked and pushed my own streams module to do some checking and repackaging of the tablet data. It works, but the system is _extremely_ slow. While the tablet is sending about 1000 bytes/sec, only about 50 bytes/sec get through, and the process that opened the stream barely crawls. There are no other processes except the usual assorted daemons. This even happens if my module eats all the data and passes nothing upstream, without doing any of the tablet-related processing. I varied the tunable parameters, but it didn't help. On SunOS 3.4 and 3.5, I used a line discipline, and had no problems at all. The same thing happens on a Unisys Convergent SPC200, running SVR3-based CTIX 3.0, so I suppose it's not a bug in SunOS (CTIX even freezes up completely, and I have to reboot). I have seen a mouse module that walks over the process table to increase its owner's priority, so I guess I am not the only one with this problem. What is going on here? I have no source access. Sorry if this came up in c.u.i before, I can't always keep up with the volume. Thanks for any help! I'll summarize email if there is interest. Thomas Driemeyer ...!pacbell!trane!thomas (don't send to pyramid!trane)