[freefolks]

in the 90's, Xmodem seemed to be a inferior protocol compared to Z-Modem and HS-Link.

[lproven]

Hint: X comes before Y which comes before Z.

They were successor protocols designed and implemented to fix perceived shortcomings in the original one.

1977: https://en.wikipedia.org/wiki/XMODEM

1985: https://en.wikipedia.org/wiki/YMODEM

1986: https://en.wikipedia.org/wiki/ZMODEM

[jpalomaki]

And then https://en.wikipedia.org/wiki/SMODEM

SModem supported simultaneous upload/download and chatting.

[karaterobot]

For what it's worth, Zmodem came about 10 years after Xmodem, and HS/Link came about 15 years after Xmodem.

[kragen]

Sure, but that's because they were designed later with the benefit of hindsight on XMODEM, and didn't have to run on such tiny machines.

[snvzz]

Yet they're both worse than Kermit, which is much older than them.

But XMODEM is still the oldest.