steveb@shade.UUCP (Steve Barber) (07/10/88)
Has anyone else noticed a problem with Pcomm not being able to keep up with a 2400bps data flow? I have an external 2400bps modem connected to my 3B1, and whenever I use Pcomm to dial out (hardly at all any more, due to this problem and the fact that I've got everything in ATE working correctly now) I can really see the speed problem. To my eye it looks like it might even be slower than 1200bps. I don't seem to have this problem when using pcomm from a terminal rather than the console. I thus suspect the console drivers for being the guilty party, rather than pcomm itself. It's just painfully obvious to me when using pcomm. I *know* the console window can display data faster than that. My question is, why is it so slow with pcomm? Maybe it's all the extra overhead of using RAW or CBREAK mode? I've noticed that you can see long ksh prompts (in emacs mode, which would be CBREAK?) printing character by character as well. I investigated the tty code in pcomm to some extent and saw no reason for it to be the cause of the problem. Am I the only one seeing this problem? BTW: has anyone hacked a terminal emulation add-on to pcomm? -- Steve Barber ...!umix!shade!steveb "Did I say that?"
karl@mstar.UUCP (Karl Fox) (07/10/88)
Pcomm is slow on output because it gets each character from the modem
with a read(fd, (char *)&c, 1) and echos it with a call to fwrite(). I
sped up my copy of Pcomm about 7-fold (I use it with a TB+) just by
changing input.c to read up to 100 characters at a time, and then
echoing them in a more efficient manner. The output is a little
bursty, but it can repaint a screen in less than 1 second at 9600 bps.
--
Karl Fox, Morning Star Technologies ...!{att,osu-cis,pyramid}!mstar!karl