3 ms·
My teenage impression of the Kermit and Zmodem protocols, written in the mid 90s: here’s my impression of how kermit works client: here is byte number 1 serve
by dmd 11y ago
My teenage impression of the Kermit and Zmodem protocols, written in the mid 90s:
here’s my impression of how kermit works
client: here is byte number 1
server: i have received byte number 1. the checksum was 3.
client: i agree that the checksum was 3.
server: ok, we’re done with byte number 1.
client: I agree, we’re done with byte number 1.
client: here’s byte number 2.
server: you know, it’s not easy being green
now zmodem zmodem goes something like this:
client: I’m gonna send you about 200k now, and you’re gonna bend over and take it
server: thank you sir! ( … )
server: ok, got 200k, checksum was 523
client: DID I ASK YOUR FUCKING OPINION?
server: NO SIR! SORRY SIR!
- bluedino 11y agoMy teenage impression of Zmodem: holy freakin' fast! After using Xmodem it was like my modem was upgraded from 14.4 to 28.8. And if someone picked up the house phone during a 3 hour download, I could continue where I left off, assuming the BBS wasn't busy by the time I called back.
- jejones3141 11y agoThat's Kermit in its very basic version, which is slow but has the advantage of working just about everywhere under extreme constraints. If you have an urge to send data from your C-64 or Tandy CoCo to a Burroughs B5500, there is or was probably a version of Kermit for each that would let you do it. Later Kermits had large packets, sliding windows, and ways to specify what characters needed special encoding.
- NoGravitas 11y agoYep. A properly configured, later version of ckermit was typically as fast or faster than zmodem (at least, as I remember from the mid-1990s).
- jamiesonbecker 11y agoYeah this was a while ago. ;) My experience was that zmodem was incredibly fast under real-world conditions. It really was like getting a speed boost on your 300 or 1200 baud (or 2400 baud, if you were lucky!) pipe. Anyone remember xmodem or ymodem as well? EDIT: I didn't realize he'd written ymodem as well! What a brilliant guy.
- jandrese 11y agoYeah, but getting Kermit properly configured required the blood of three chickens and a wizard. Z-Modem had sane defaults right out of the box.