9 Dec
2017
9 Dec
'17
5:38 a.m.
Folks,
The tn3270 support in Hercules emulates channel attached 3270's not bi-sync so may not
be a good source of info. On a local 3270 controller each screen has a unique
channel-controller-device address.
On a bi-sync device only the line going to the device, additional addressing is required
using poll/select sequences...
The total reference book is the Datastreams Programmers Reference.
http://www.bitsavers.org/pdf/ibm/3270/GA23-0059-4_3270_Data_Stream_Programm…
This covers most of what you want to know. Chapter 9 covers the differences encountered in
a bi-sync environment.
If you need to understand the lower level bi-sync and the poll-select protocols, which I
think may be what is blocking you at present try this:-
http://www.euclideanspace.com/coms/protocol/bi_sync/dlc/index.htm
its not wonderful but it may help. Looking at the chapter on 3270's in the VM sysgen
might help explain the addressing (it might not)...
http://www.bitsavers.org/pdf/ibm/370/VM_370/Release_6/GC20-1801-10_VM370_Sy…
Dave
-----Original Message-----
From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Guy
Sotomayor Jr via cctalk
Sent: 09 December 2017 01:38
To: Charles Anthony <charles.unix.pro at gmail.com>; General Discussion: On-
Topic and Off-Topic Posts <cctalk at classiccmp.org>
Subject: Re: IBM 3270 controller emulation
It might be worthwhile to look at the source for hercules (370, 390, z/series)
emulator since that includes support for 3270 terminals through tn3270. It?s
pretty good since I can use actual 327x CUT terminals connected to a 3174
controller which connects to hercules emulating the mainframe.
TTFN - Guy
On Dec 8, 2017, at 5:22 PM, Charles Anthony via
cctalk
<cctalk at classiccmp.org> wrote:
>
> I am trying to wire 3270 support into the DPS8/M emulator.
>
> Multics supports 3270 via a bisync connection to the 3270 controller.
> Multics sends commands to the Front End Network processor, which
> (originally) passed the commands down the bisync line to the 3270.
>
> I have a running Multics and running 3270 display emulators using
> tn3270
> (3270 over telnet), so I need to write the code that maps the Multics
> commands into 3270 controller commands (and vice versa) and manages
> the telnet connections to the 3270 display emulators and maps the
> tn3270 traffic into 3270 controllers.
>
> I don't need to actually implement the bisync communications; the
> controller emulator will be running inside the FNP emulator, but I
> need to express controller responses to Multics in the bisync format,
> as Multics is expecting that the responses arrived over a bisync connection.
>
> The problem is that I have no idea how the 3270 controllers worked;
> I've looked through the bitsavers collection; those documents are
> largely concerned with the displays and tend to treat the controllers
> as 'black boxes' that just do the right thing.
>
> So I am seeking pointers to documentation that will give me a better
> grasp of the controller functionality and/or discussions with someone
> who knows how they work.....
>
> Thanks,
> -- Charles