chk@alias.UUCP (C. Harald Koch) (11/15/89)
What is the difference between the ttyd*, ttym*, and ttyf* devices? What do the various bits in the minor device number really do? From scouring the manuals, I have managed to find that ttym* is meant for modems, which probably means that an open() call won't return until DCD is set. I can't find anything else, other than an obscure reference to the Owner's Guide (which doesn't say anything useful). aTdHvAaNnKcSe, -- C. Harald Koch Alias Research, Inc., Toronto ON Canada chk%alias@csri.utoronto.ca chk@gpu.utcs.toronto.edu chk@chk.mef.org
vjs@rhyolite.wpd.sgi.com (Vernon Schryver) (11/15/89)
In article <619@alias.UUCP>, chk@alias.UUCP (C. Harald Koch) writes: > What is the difference between the ttyd*, ttym*, and ttyf* devices? What do > the various bits in the minor device number really do? ttyd* use RD,TD, and SG RS-232-C fashion. DTR & RTS will be + when the device is open, unless HUPCL has been fiddled. ttym* is the same ttyd*, except that DCD is waited for on open (unless NODELAY is set--used by uugetty), and causes SIGHUP and forced-close upon a falling edge. ttyf* is the same as ttym*, except CTS controls output as RS-232-C directs, and RTS follows the industry practice, non-RS-232-C-standard flow control scheme. That is, RTS low tells the device to stop talking. > From scouring the manuals, I have managed to find that ttym* is meant for > modems, which probably means that an open() call won't return until DCD is > set. I can't find anything else, other than an obscure reference to the > Owner's Guide (which doesn't say anything useful). > -- > C. Harald Koch Alias Research, Inc., Toronto ON Canada > chk%alias@csri.utoronto.ca chk@gpu.utcs.toronto.edu chk@chk.mef.org Essentially the preceding words are in text and tables in at least one of the manuals. I know because I regularly get the help necessary to find them, and because we spent lots of memorable time arguing over exactly what would be enough but not so much as to be confusing. Unfortunately, I must have a mental block about where these words are, because I can NEVER find them without help. Use ttym for slow modems. Use ttyf for fast modems which want "hardware flow control", such as TB's. Vernon Schryver Silicon Graphics vjs@sgi.com