Hmm… I remember zmodem being noticeably faster, more reliable, and flexible compared to its predecessors. But I think of it as ahead of its time inasmuch as what followed seemed a definite step back. Internet-based protocols which replaced it were quite a bit slower due to latency issues and what not, and it would take quite some time for new approaches to surface. Today, we have the like of bittorrent which does leap ahead in many ways but that was a long time coming.
Technically speaking, it wasn’t replaced by IP-based utilities, since they have different functions. Zmodem is intended for sending binary files over an ASCII-based (7-bit) serial line, whereas the Internet-based protocols send files over IP, which is a packet-based networking protocol. That’s where the performance difference comes in, since TCP/IP has significant overhead in the form of TCP and IP headers in each 1500-byte packet, plus extra processing costs on each end. That overhead brings with it far more flexibility in connecting to any arbitrary host on the network to transfer files, not just the two on either end of a serial line.
(It wasn’t even replaced, since it’s still available on my computer right now, installed as a dependency of something or other. I think the last time I used it was to transfer a file to an embedded device.)
Hmm… I remember zmodem being noticeably faster, more reliable, and flexible compared to its predecessors. But I think of it as ahead of its time inasmuch as what followed seemed a definite step back. Internet-based protocols which replaced it were quite a bit slower due to latency issues and what not, and it would take quite some time for new approaches to surface. Today, we have the like of bittorrent which does leap ahead in many ways but that was a long time coming.
Technically speaking, it wasn’t replaced by IP-based utilities, since they have different functions. Zmodem is intended for sending binary files over an ASCII-based (7-bit) serial line, whereas the Internet-based protocols send files over IP, which is a packet-based networking protocol. That’s where the performance difference comes in, since TCP/IP has significant overhead in the form of TCP and IP headers in each 1500-byte packet, plus extra processing costs on each end. That overhead brings with it far more flexibility in connecting to any arbitrary host on the network to transfer files, not just the two on either end of a serial line.
(It wasn’t even replaced, since it’s still available on my computer right now, installed as a dependency of something or other. I think the last time I used it was to transfer a file to an embedded device.)