friedl@vsi.UUCP (Stephen J. Friedl) (02/27/88)
Netpeople,
We've been running a 3B2/400 for a while and have been
through a number of releases of the operating system. One chron-
ic problem is that PORTS cards (the ones with a parallel port
and four serial ports) seem to add delays when backspaces are
written. Try this:
$ echo "xxxxxxxxxxxxxxxx\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b"
and watch the cursor blow by the xxxxx and then move noticeably
slower on the backspaces -- I timed it at around 300 baud.
There are no backspace delays set via termio -- I wrote a hand-
full of little programs to open the port in absolutely *raw* mode
to no avail -- but I still get the delays. If I set the high bit
the \b goes out quickly, and this problem does occur on the EPORTS
cards.
I have seen this on every 3B2 I have been on and AT&T has no
answer for me. Has anybody else seen this? Any suggestions?
I've already rewritten some of my termcap/terminfo entries to use
alternate move-the-cursor-left strings but sometimes there are no
other ways than to use backspace. Sigh.
Thanks,
Steve
--
Life : Stephen J. Friedl @ V-Systems, Inc/Santa Ana, CA *Hi Mom*
CSNet: friedl%vsi.uucp@kent.edu ARPA: friedl%vsi.uucp@uunet.uu.net
uucp : {kentvax, uunet, attmail, ihnp4!amdcad!uport}!vsi!friedlbron@cit5.oz (Barry Bron) (03/07/88)
In article <55@vsi.UUCP> friedl@vsi.UUCP (Stephen J. Friedl) writes: > We've been running a 3B2/400 for a while and have been >through a number of releases of the operating system. One chron- >ic problem is that PORTS cards (the ones with a parallel port >and four serial ports) seem to add delays when backspaces are >written. We have a 3B2/400 running Version 5.3 and had noticed the problem when I installed some new software and found that by using the command " stty ofill " the problem was solved. I don't know why but it works for us. It appears there is no diference if you use either " ofdel " or " -ofdel ". They both work, but is this another problem or is it the fix. I leave that to others with more knowledge about unix. Barry Bron (bron@cit5.oz)
ray@dsiramd.nz (Ray Brownrigg) (03/10/88)
In article <218@cit5.oz> bron@cit5.oz (Barry Bron) writes: >In article <55@vsi.UUCP> friedl@vsi.UUCP (Stephen J. Friedl) writes: > >> We've been running a 3B2/400 for a while .... One chron- >>ic problem is that PORTS cards ... seem to add delays when backspaces are >>written. > > We have a 3B2/400 running Version 5.3 and had noticed the problem >when I installed some new software and found that by using the command >" stty ofill " the problem was solved. I don't know why but it works for us. >It appears there is no diference if you use either " ofdel " or " -ofdel ". I have been mildly bothered by this for a while also. Probably since we installed SVR3.0. Following up on the "stty ofill"; that works because the delays that are built into each backspace (0.05 secs) are replaced by a single character (either NUL or DEL depending on ofdel or -ofdel), so anything faster than 200 BAUD will see a speed improvement. Now the real problem is why delays at all? It appears that "stty bs0", which should turn off backspace delays, is the problem. Backspace delays are put in (by the tty driver?) independently of the BSDLY field in the c_oflag entry of the termio structure for a terminal. Thus the "stty ofill" is a workaround to the bug caused by backspace delays being output regardless of whether or not they are requested. I have put an "stty ofill" command into my /etc/profile. -- Ray Brownrigg <ray@dsiramd.dsir.govt.nz> DSIR Applied Maths Div System: OLIVETTI/AT&T 3B2/400B+, System V R3.0 PO Box 1335, Wellington, New Zealand "UNX -rules -OK"