woods@eci386.uucp (Greg A. Woods) (11/19/90)
In article <1990Nov15.225853.26239@decuac.dec.com> mjr@decuac.dec.com (Marcus J. Ranum) writes: > has anyone ever written a modem multiplexer for windows ? something > that would allow me to, say, open 4 windows on my Sun at home, with their > input all channeling to a process that tags each packet with a window number > before sending it across the line to a server on a remote host which then > demultiplexes and sends the data to an equal number of ptys on that host, > and reverses the process ? It's kind of a bummer to have windows on a > workstation at home but only one remote connection. (SLIP is out) > > anyone done this yet ? Yup. AT&T. It's called the "AT&T Windowing Utilities". It is part of SysVr3.0 and newer (and was available for r2.0). It uses a protocol called layers, supported by a device driver called xt, and works with various AT&T terminals (blit, 5620DMD, 615MTG, 630MTG, 705, 730, etc.) Layers is based on work done by Rob Pike (Bell Labs) for the original blit (or was it the jerq :-) windowing terminal. The original multiplexor was called mux, and I've heard there is a streams version of mux in V10. For more info. on the history, see the Bell Systems Technical Journal articles about the blit (1984 UNIX volume, I think). The blit, 5620, 630, and 730 have lots of RAM and support downloading of software into the terminal for various fun programmes, such as troff previewers, drawing programmes, games, etc. (These terminals are also graphics terminals.) Much of this software is available through the AT&T Toolchest for very little $$. These terminals run a firmware based OS called layersys. The best little "dumb" terminal available for few dollars today is, IMHO, the AT&T 705, and it supports two (character-only) windows running layers. Word has it that someone in Bell Labs once wrote a similar thing to layersys for the IBM-PC (actually the AT&T 6300). There is a user-code version of the "driver" for BSD-like hosts. It is probably covered by AT&T SysV source license. There is considerable interest in the Toronto area in writing another implementation for PC's, and perhaps Macintosh. There is also considerable interest in re-implementing the xt driver and layers software for the host end too (because of various silly limitations and because of stupid vendors who don't support layers). This interest may be driven by the fact that there are a good number of new owners of 5620's in this area. If you can find a used one (or a used 630, or 730), or can afford a new 730 (~$3500CDN), they are wonderful to use.... -- Greg A. Woods woods@{eci386,gate,robohack,ontmoh,tmsoft}.UUCP ECI and UniForum Canada +1-416-443-1734 [h] +1-416-595-5425 [w] VE3TCP Toronto, Ontario CANADA