Subj : Re: kermit protocol in syncterm
To : fusion
From : Digital Man
Date : Fri Aug 18 2023 07:02 pm
Re: Re: kermit protocol in syncterm
By: fusion to Digital Man on Fri Aug 18 2023 08:23 pm
> On 18 Aug 2023, Digital Man said the following...
>
> DM> YMODEM-G is a protocl. gkermit is a terminal transfer protocol driver.
> DM> You're comparing apples and oranges. If you want to compare X/Y/ZMODEM
> DM> protocol performance, you should be comparing with the reference
> DM> X/Y/ZMODEM protocol implementation (rz/sz).
>
> sorry i misspoke. i can see gkermit (and by extension, kermit. just to spell
> it out) outperforming sexyz's ymodem-g.
Okay. <shrug>
> you asserted ymodem-g shouldn't have any overhead and should be as fast or
> faster than kermit. is that in theory?
Correct, I'm talking about the protocol itself. Unless you're using a compression feature with Kermit (are you?), it's really impossible for the Kermit *protocol* to outperfrom Ymodem-G protocol over the same TCP/IP link - removing any implementation details. Ymodem-G simply has near zero over head over TCP/IP and no wait for acknowlegement of any subpacket data, so the only want to get *faster* is to use a protocol with literally zero data overhead (e.g. FTP) or to use some kind of data compression.
> because i tested ymodem-g with sexyz
> and it performs extremely poorly with incredible overhead. (again,
> sexyz->syncterm)
"Overhead" refers to the amount of extra data that is sent in addition to the actual payload (file) data. It's not really relevant in that sentence. The overhead is a function of the protocol, not the impplementation. Anyway, okay, so you found gkermit outperms sexyz in your particular test environment. Cool.
> if i compare to the reference implementation of rz/sz what am i trying to
> prove?
Your initial messages said you were comparing Kermit to Zmodem. If that's what you really want to do, use the reference implementation of Zmodem by Chuck Forsberg for your tests.
> that sexyz's ymodem-g (or zmodem) works better with the reference
> implementation than with itself? or am i proving both perform poorly
> compared to kermit?
>
> you mentioned zmodem shouldn't be far /behind/, yet it performs better than
> ymodem-g with sexyz.
Faster than Ymodem-G? Not under my tests. And there's no technical reason why it should.
> people are easily using it correctly and getting poor results where they
> shouldn't be. so they try kermit and it blows sexyz out of the water. after
> which you chime in and say "use ymodem-g it should be even better!" .. well
> i'm saying that doesn't pan out in real life.
Your "real life" test is over a localhost link or a local network? Why on earth would you be using a serial/modem file transfer protocol over a local network (Ethernet, WiFi?) and call that "real life"?
--
digital man (rob)
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