On Thu, 02 Jun 2016 05:41:40 -0400, Gene Heskett wrote: > On Thursday 02 June 2016 04:13:51 alister wrote: > >> On Thu, 02 Jun 2016 18:50:34 +1200, Gregory Ewing wrote: >> > jlada...@itu.edu wrote: >> >> One common data transmission error I've seen in other systems is >> >> added/dropped bytes. I may add a CRC-8 error-checking byte in place >> >> of the newline. >> > >> > Also maybe add a start byte with a known value at the beginning of >> > each packet to help resynchronise if you get out of step. >> >> No maybe about it if you are sending a binary stream you need to be >> able to reliably signal the start AND finish of the data stream (either >> send the length in the message start or have a fixed msg. length) >> >> after a lot of experimenting to ensure reliability you will probably >> have reinvented something like intelhex or x-modem >> > Neither of which can handle that last packet well unless the last packet > is padded out to be a fill packet and the filler bytes thrown away in > the receiver.
The examples quoted were for examples of binary transfer protocols & not intended to be an exhaustive list. > >> The work [of software development] is becoming far easier (i.e. the >> tools we're using work at a higher level, more removed from machine, >> peripheral and operating system imperatives) than it was twenty years >> ago, and because of this, knowledge of the internals of a system may >> become less accessible. >> We may be able to dig deeper holes, but unless we know how to build >> taller ladders, we had best hope that it does not rain much. >> -- Paul Licker > > Paul is absolutely correct. > > Cheers, Gene Heskett ^^^^ like that quote -- Under deadline pressure for the next week. If you want something, it can wait. Unless it's blind screaming paroxysmally hedonistic... -- https://mail.python.org/mailman/listinfo/python-list
