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---In [email protected], <dave.g4ugm@...> wrote :
...
> What is pissing me off is his fixation with running character mode software on IBM mainframes.
> Yes you can do it on a modern machine but to me its done in such a complex way its more un-IBM > than the way Paul does it.
> It still must be horribly inefficient because the LAN interface must be generating an interrupt per
> packet when running like this?
> Dave
...
> Please keep discussion about character mode terminals on the 380 list. The only way that character > mode terminals get into a Mainframe is via TCPIP.
> The rest, its line at a time block mode/ line mode all the way...
> ... and did you know that even the VT100 does block mode, just DEC never used it much, Not sure > if its part of the ANSI spec...
> Dave
Back in the day, one could attach character mode terminals, even ASCII ones, via a 2705 or 3705 communications controller. Teletypes were attached that way.
There were also IBM Selectric-based hardcopy terminals, which, of course, were character based as well (e.g., IBM 2741), also typically attached via a 2705 or 3705.
Another way it was done was to use a "protocol converter". The protocol converter looked to the mainframe like an SDLC attached 327x controller. It managed the screen buffer / block mode stuff, and used the character mode terminal as the display / keyboard over RS-232. One of those was manufactured by "Protocol Computers, Inc.".