root@zswamp.uucp (Geoffrey Welsh) (06/04/91)
In a letter to All, Robert D. Thompson (rdthomps@vela.acs.oakland.edu ) wrote: >What kind of throughput can one expect on compressed >files over V.32bis ? That depends on protocol; streaming protocols like ZMODEM or YMODEM-G should give 1750 CPS or so unless you're calling a modem that doesn't support V.42 or MNP (which isn't all that common these days). >From the discussions, I gather that it does not >degrade below 9600 because of error-correction, flow, etc... I can't for the life of me guess what that means. >I also gather that it does not take advantage of >compression, and thus does not exceed 9600 ? Perhaps the most important thing that a reader can learn from this conference is that data compression has absolutely nothing to do with the modulation protocol. V.32bis is a modulation protocol (it describes how bits are converted into signals for the phone line, and nothing more), and it does not include data compression... but neither does any other modulation standard. You follow? >So...will compressed (or randome) files pretty much >stay at 9600 baud throughput ? They'd better not, since V.32bis is a 14,400 bps modulation protocol. -- Geoffrey Welsh - Operator, Izot's Swamp BBS (FidoNet 1:221/171) root@zswamp.uucp or ..uunet!watmath!xenitec!zswamp!root 602-66 Mooregate Crescent, Kitchener, ON, N2M 5E6 Canada (519)741-9553 "He who claims to know everything can't possibly know much" -me
rdthomps@vela.acs.oakland.edu (Robert D. Thompson) (06/05/91)
In article <154.284B10AF@zswamp.uucp> root@zswamp.uucp (Geoffrey Welsh) writes: >In a letter to All, Robert D. Thompson (rdthomps@vela.acs.oakland.edu ) wrote: > > >What kind of throughput can one expect on compressed > >files over V.32bis ? > > That depends on protocol; streaming protocols like ZMODEM or YMODEM-G >should give 1750 CPS or so unless you're calling a modem that doesn't support >V.42 or MNP (which isn't all that common these days). > >Geoffrey Welsh - Operator, Izot's Swamp BBS (FidoNet 1:221/171) >root@zswamp.uucp or ..uunet!watmath!xenitec!zswamp!root >602-66 Mooregate Crescent, Kitchener, ON, N2M 5E6 Canada (519)741-9553 >"He who claims to know everything can't possibly know much" -me Geoffrey, So are streaming protocols like ZMODEM and YMODEM-G better than say Kermit when it comes to transfer performance. I know that ZMODEM is faster in general, but is it specifically better for transfer over V.32bis Modems? What are the advantages and disadvantages of each protocol in terms of high-speed transfers of pre-compressed files (like *.ZIP)? Thanks for your help - please don't be too hard on me because of something I don't know - "You Follow?" |(8> --- Robert rdthomps@vela.acs.oakland.edu
glendwer@cats.ucsc.edu (Craig Steven Bell) (06/05/91)
If you use BiModem, you can expect @1775cps going in BOTH directions. Why settle for less? BiModem supports crash recovery, batch, 4096 byte blocks, and 115k DTE rates. ..and chat.
les@chinet.chi.il.us (Leslie Mikesell) (06/06/91)
In article <16641@darkstar.ucsc.edu> glendwer@cats.ucsc.edu (Craig Steven Bell) writes: >If you use BiModem, you can expect @1775cps going in BOTH directions. >Why settle for less? >BiModem supports crash recovery, batch, 4096 byte blocks, and 115k DTE rates. >..and chat. Is unix source available? Where? Les Mikesell les@chinet.chi.il.us