ymodem, zmodem

ney25 · ‎08-26-2007

Hi,

anyone can tell me what is ymodem and zmodem use for ?

thanks a lot.

regards,

skywalker

Joseph W. Doherty · ‎08-26-2007

Ymodem and zmodem (and xmodem) were (old) protocols used to transfer files across serial links. Normally found in terminal emulators (e.g. HyperTerminal). Dial-up bulletin board systems (BBS) used them when you wanted to download or upload files. (In days of yore, vendors often had a BBS that you could dial-up and download patches.)

On much (all?) Cisco equipment, you can also upload a software image across the console serial port using one of these.

ney25 · ‎08-26-2007

Hi Josephdoherty,

thanks for the update, but i still dont understand if these 3 protocol are used to upload and download then what dont just come with 1 protocol like xmodem is good enough instead of ymodem then zmodem ? doesn't make sense, right ? it must be some usage between these 3 ?

regards,

skywalker

Joseph W. Doherty · ‎08-26-2007

Ah, well over time various individuals made protocols that did the same thing, but did it "better" (with these "better" was usually faster and/or better error handling).

The sequence was, I believe, Xmodem, Ymodem, and the Zmodem. Some had variants with the same protocol.

Normally, when you have a choice, you chose the latest or "best" version that both sides support.

ney25 · ‎08-26-2007

Hi Josephdoherty,

really thanks a lot, at least now i have some idea what does it use for .

thanks a lot.

regards,

skywalker