🚀 go-pugleaf

In article <9101091607.AA01872@lilac.berkeley.edu> Pam Williams <hpda!hpcuhc!pjw@ucbvax.Berkeley.EDU> writes:
>I am finding that when using a sna3270 terminal
>emulator to an IBM host with a BINDed RU size of 1K, a few
>host applications still send security screens
>in one RU of larger than 1K to the 3270 terminal.
>The 3270 emulator doesn't like this and sends
>back a neg response.
> .....
>However, I don't understand why I would
>be receiving the larger RU in the first
>place.
>
>How can VTAM be sending a RU larger than
>the value set in the BIND?

The 3174 Subsystem Control Unit Functional Description (GA23-0218)
has several comments on RU sizes.  One of them leads you to believe that it
does check outbound (from host to device) RU sizes against BIND values, but
the sense code that would be used to report the error (X'1002') is only
returned by a Type 1 LU (printer).

It also says that for remote models, for LU Type 2 and 3, there "are no
restrictions" on the outbound RU size.  Whether that is meant to include
checking against BIND limits is left quite *un*clear in the document.

This appears to be the same for a 3276, based on an older Component
Description I have.

This is a classic area where 3270 emulators run into IBM not following
their own architecture in hardware implementations.
-- 
Tom Gillispie               Internet: gillispi@tinton.ccur.com  (201) 758-7329
Concurrent Computer Corp.   UUCP:............rutgers! \
106 Apple St.                 ..princeton! or masscomp!- petsd!tinton!gillispi
Tinton Falls NJ 07724         .....purdue! or encore! /