"As the article states, no sensible application does 1-byte network write() syscalls." - the problem that this flag was meant to solve was that when a user was typing at a remote terminal, which used to be a pretty common use case in the 80's (think telnet), there was one byte available to send at a time over a network with a bandwidth (and latency) severely limited compared to today's networks. The user was happy to see that the typed character arrived to the other side. This problem is no longer significant, and the world has changed so that this flag has become a common issue in many current use cases.
Was terminal software poorly written? I don't feel comfortable to make such judgement. It was designed for a constrained environment with different priorities.
sure, but we do so with much better networks than in the 80s. The extra overhead is not going to matter when even a bad network nowadays is measured in megabits per second per user. The 80s had no such luxury.
Not really. Buildout in less-developed areas tends to be done with newer equipment. (E.g., some areas in Africa never got a POTS network, but went straight to wireless.)
Yes, but isn't the effect on the network a different one now? With encryption and authentication, your single character input becomes amplified significantly long before it reaches the TCP stack. Extra overhead from the TCP header is still there, but far less significant in percentage terms, so it's best to address the problem at the application layer.
It was not just a bandwidth issue. I remember my first encounter with the Internet was on a HP workstation in Germany connected to South-Africa with telnet. The connection went over a Datex-P (X25) 2400 Baud line. The issue with X25 nets was that it was expensive. The monthly rent was around 500 DM and each packet sent also had to been paid a few cents. You would really try to optimize the use of the line and interactive rsh or telnet trafic was definitely not ideal.
Was terminal software poorly written? I don't feel comfortable to make such judgement. It was designed for a constrained environment with different priorities.
Anyway, I agree with the rest of your comment.