On 2018-05-22, Grant Taylor <gtay...@gentoo.tnetconsulting.net> wrote:
> Aside: Now my brain is trying to remember the old differences between
> telnet and 3270 / 5250. I think that telnet was inherently line
> oriented (by default) and 3270 / 5250 were something else (but I don't
> remember what).
The 3270 was completely screen-oriented. An entire screen was loaded
from the host. That screen included fields with various attributes
(e.g. editable vs. read-only). You could edit whatever was editable
on the screen, and then when you hit "submit" the entire screen was
sent to the host (there may have been an option to send only edited or
editable fields, I don't remember the details). IOW, it worked
vaguely like an HTML page containing a form. Except there were
various entertaining ways things went wrong that don't happen with an
HTML form. IIRC, if you inserted too much data into an improperly
defined field, it could shift everything below it and muck up all the
rest of the fields. I also seem to recall sometimes being able to
edit fields that weren't really supposed to be editable, and then
hilarity ensued when you hit submit.
Though I did actually use some genuine IBM green-screen "3270-like"
terminals, most of my experience was with 3270 emulators running under
X11 -- so some of the fun was probably caused by bugs in the
emulators.
--
Grant Edwards grant.b.edwards Yow! I'm shaving!!
at I'M SHAVING!!
gmail.com
