Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!mailrus!ames!sgi!calcite!vjs From: vjs@calcite.UUCP (Vernon Schryver) Newsgroups: comp.unix.wizards,comp.unix.i386 Subject: Re: STREAMS tty drivers for SysV Summary: probably not Message-ID: <45@calcite.UUCP> Date: 11 Jun 89 00:07:37 GMT References: Distribution: comp Organization: Rhyolite Software, Mountain View, CA Lines: 29 In article , klemets@sics.se (Anders Klemets) writes: > ... > On SUN 4.0 the ttys are STREAM devices, but definitely not on this > System V box. > Does anybody know if the ttys are STREAM devices on the Interactive > Systems 386/IX OS? ... It is impossible to put a SVID-compliant tty under the SVR3.[012] stream head as it comes on the 3B2 source tapes. There is no provision for VTIM/VMIN in the SVR3 streams head, and you cannot do it below the head in SVR3 streams. Also, the SVR3 stream head believes a non-blocking read returns EAGAIN like BSD ttys and other, reasonable SV devices, instead of 0 like SVID tty's. Sun may have an advantage or two. Did they put a BSD "new tty" style driver under their streams, instead of something current-SVID-compliant? They might reasonably expect someone to listen to their requests to change the next version of the SVID. They may also have modified the stream head. I can authoritatively state that at least one SVR3 vendor is shipping a SVID-compliant streams tty driver, based on an extended streams head. You also need streams character drivers for the bottom, and some kind of line discipline module. The one I did is not small, even if the stack is 12x faster than what it replaced. It would be impossible to correctly emulate each and every bug (oops, I mean feature) of the ancient tty driver without source. Vernon Schryver vjs@calcite.uucp