[Info-vax] Using terminal lines - a long shot question

[Jan-Erik Söderholm]

Den 2020-03-08 kl. 21:27, skrev Lee Gleason:
> 
>    I have occasion to write some programs that control some foreign gear 
> via terminal lines (I know - already, I am in a state of sin...).
> 
>    Many years back, Jamie Hanrahan (RIP) posted an entry to comp.os.vms 
> that described in great detail the best way to do this sort of thing - it 
> described when to use what sort of read qio's, from single character reads 
> with timeouts to bulk reads by length, and several types in between those, 
> and when to switch to which variety. It went on at length how to do this 
> sort of thing efficiently and reliably. It was a great generalized 
> description of how to deal with gear that needs to send and receive small 
> commands as well as large data packets - a sort of universal treatment of 
> how best to implement an asynchronous protocol
> 
>    I've misplaced my copy of that post - wondering if anyone else saw it 
> and saved a copy....
> 
> -- 
> Lee K. Gleason N5ZMR
> Control-G Consultants
> lee.gleason at comcast.net

What is a "terminal line" more specifically? Is it a physical hardware
serial port? Or can it also be ports like LAT LTAxxx or telnet TNAxxx
devices? Connected to some sort of terminal server with serial ports?

And how large is a "large data package"?