kadie@cs.uiuc.edu (Carl M. Kadie) (10/05/90)
Is it practical to run X over a fast modem? Is V.32 (9600 baud) modem with V.42bis compression fast enough? -- Carl Kadie --- kadie@cs.uiuc.edu University of Illinois at Urbana-Champaign === Today the NEA and alt.sex, tomorrow our public libraries ===
mikeh@bryant.NCD.COM (Mike Harrigan) (10/06/90)
In article <1990Oct5.023310.12638@ux1.cso.uiuc.edu>, kadie@cs.uiuc.edu (Carl M. Kadie) writes: |> Is it practical to run X over a fast modem? |> Is V.32 (9600 baud) modem with V.42bis compression fast enough? |> Network Computing Devices has a product called XRemote that allows you to use our X terminals over RS232 lines either with direct connection (up to 38.4Kbaud) or on V.32 modems (9600 baud). You can run slower, but performance suffers. The way it works is you get special PROMs for the NCD terminal that contain the X server code and the XRemote communications code. The XRemote code does both data compression and end-to-end error checking. On the host computer you need an XRemote binary that provides the communication at the host side. Currently NCD supplies binaries for Suns, but we have DEC/Ultrix and DEC/VMS ports underway. Also NCD makes the source code for XRemote available to systems vendors, so MIPS, Sequent and others have ports underway. XRemote does not make use of modem compression because most modem compression techniques affect latency which causes X applciations to feel uncoordinated. What works best is a full duplex modem, typically V.32. You probably want to know about performance of XRemote compared to Ethernet and/or SLIP. We find that at 9600 baud it is much faster than SLIP (about a factor of 10), but still not as fast as Ethernet. At 38.4 kbaud you start approaching Ethernet speeds for some applications. Still, it is a good way of getting X in a remote location at a low price. If you have more questions, please contact NCD via email at info@ncd.com. Mike Harrigan Network Computing Devices mikeh@ncd.com
kadie@thucydides.cs.uiuc.edu (Carl M. Kadie) (10/13/90)
In <1990Oct5.023310.12638@ux1.cso.uiuc.edu> I write: >Is it practical to run X over a fast modem? >Is V.32 (9600 baud) modem with V.42bis compression fast enough? Here is a summary of responses: -------------- Yes: GraphOn OptimaX 200 -- V.32/V.42bis Doubt a SLIP/X would work well -------------- Text will fare quite a bit better than graphics. SL/IP's fairly slow. Some X terminals run the actual server on the host. I can really feel the difference between a direct connection and a Telebit running at 9600 baud. --------------- V.32 is acceptable on a Graphon X terminal (server in the host, compressed serial proprietary protocol) ------------ NCD xterminal's practical. Not as much fun as having a SparcStation, but OK. ------------ AT clone, PC-XView (from GSS), and FTP network software with SLIP, and SLIP in the Ultrix (DEC) environment. -> 9600 didn't exactly blaze, but it wasn't too bad. 4800 was hard to use, 2400 losed big time. --------------------- Thanks for your input. I hope QuarterDeck is listening. I think usability at 9600 baud could be a big selling point for their DesqView/X product. -- Carl Kadie --- kadie@cs.uiuc.edu University of Illinois at Urbana-Champaign === Today the NEA and alt.sex, tomorrow our public libraries ===