> I tried downloading a six megabyte file once which used up about 4 hours of my monthly quota, only for the file transfer to be aborted right near the end. I n

> I tried downloading a six megabyte file once which used up about 4 hours of my monthly quota, only for the file transfer to be aborted right near the end. I nearly cried. The ability to resume an interrupted transfer was a huge benefit in the ZMODEM protocol, as compared to its predecessors XMODEM and YMODEM. https://en.wikipedia.org/wiki/ZMODEM https://en.wikipedia.org/wiki/ZMODEM There were lots of innovations in this area, many of them having to do with how unreliable modem connections could be (both in terms of possibly un-hardware-corrected line noise, and in terms of the risk of having your connection hang up in the middle). https://en.wikipedia.org/wiki/Comparison_of_file_transfer_protocols#Serial_protocols https://en.wikipedia.org/wiki/Comparison_of_file_transfer_pr... I sure felt safer when I was downloading a big file with ZMODEM rather than XMODEM. :-)