jeh@sisd.kodak.com (Ed Hanway) (10/12/90)
joseph@valnet.UUCP (Joseph P. Hillenburg) writes: >jeh@sisd.kodak.com (Ed Hanway) writes: > >> papa@pollux.usc.edu (Marco Papa) writes: >> >In article <1990Oct8.193808.21972@ux1.cso.uiuc.edu> jbn35564@uxa.cso.uiuc.ed >> >>Why not fix the XPR Zmodem? >> >> >There is really nothing to fix. XPR-Zmodem has an inherent overhead due to >> >the external protocol definition. >> >> Then why not fix the external protocol definition? Or what I really mean >> is extend it to make it capable of handling full-duplex streaming protocols >> without degradation. > >The fact that the protocol is *external* is why it isn't as fast as an >internal protocol. Perhaps my overuse of the word "protocol" wasn't clear. If XPRZmodem is slow because the interface between the terminal program and the XPR library isn't adequate for a full-duplex streaming protocol like Zmodem, then enhance that interface. From my brief perusal of the XPR spec, the interface between the terminal program and the XPR library looks very clean, but tailored to half-duplex, synchronous protocols like Xmodem. The fact that the Zmodem XPR is shoehorned into this interface probably accounts for its performance (or lack thereof). With an improved interface, there's no reason why an "external" protocol should have any more overhead than an "internal" one. Ed Hanway uunet!sisd!jeh