lphillips@lpami.wimsey.bc.ca (Larry Phillips) (03/09/90)
In <6828@hydra.gatech.EDU>, gt4662b@prism.gatech.EDU (BRANHAM,JOSEPH FRANKLIN) writes: >After looking at the new Fish disks, I noticed a program which supports> >the XPR protocol. > >What is it? XPR is a method of allowing any protocol to be implemented as a program external to the terminal program. It is implemented as a shared library, and all the terminal program needs to do is to call the appropriate routines in the library, and to provide the appropriate 'callback'; routines for such terminal oriented things as getting or sending serial port data, checking the keyboard, and so on. It means that a terminal program author can impelment XPR, and be assured that the user can choose any XPR protocol available. >I've also heard rumors of a reasonably neat protocol which allows uploads >and downloads in both directions at once. Has anyone implemented this on >an Amiga? How badly does it slow down transfers? I don't know which one you are speaking of, but the principle is that in any protocol transfer, the majority of the data flows in one direction, and the other direction only carried acknowledgements or error reporting to tell the sender that something was either received, or was in error. Because of this, one direction is virtually unused, and can be used for transfer of data the other way. The only performance degradation is due to the amount of overhead incurred by the handshaking, which is minimal (a few percent at most, for most prootcols. Additionally, it is also possible to interleave other types of transfer that can happen at the same time as the up/download. 'CHAT' is a good example. Yes, it will steal a few cycles fron the up/download, but typing speeds are such that the degradation is small indeed. -larry -- Entymology bugs me. +-----------------------------------------------------------------------+ | // Larry Phillips | | \X/ lphillips@lpami.wimsey.bc.ca -or- uunet!van-bc!lpami!lphillips | | COMPUSERVE: 76703,4322 -or- 76703.4322@compuserve.com | +-----------------------------------------------------------------------+
gt4662b@prism.gatech.EDU (BRANHAM,JOSEPH FRANKLIN) (03/09/90)
After looking at the new Fish disks, I noticed a program which supports the XPR protocol. What is it? I've also heard rumors of a reasonably neat protocol which allows uploads and downloads in both directions at once. Has anyone implemented this on an Amiga? How badly does it slow down transfers? Curiousity calls. -- <------------------------------------------------------------------------------> < FRANK BRANHAM | "I exist; therefore I am." > < Georgia Institute of Technology | -The Patchwork Quilt > < Internet: gt4662b@prism.gatech.edu | by August Derleth >
papa@pollux.usc.edu (Marco Papa) (03/10/90)
In article <6828@hydra.gatech.EDU> gt4662b@prism.gatech.EDU (BRANHAM,JOSEPH FRANKLIN) writes: >After looking at the new Fish disks, I noticed a program which supports >the XPR protocol. What is it? The last batch of Fish Disks includes XPR-Kermit, an XPR-based Kermit, amiga-tized by myself and Steve Walton. -- Marco -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= "Xerox sues somebody for copying?" -- David Letterman -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=