Re: FW: Re: 5250 Data Stream Operation Codes

["Jason M. Felice" <jasonf@xxxxxxxxxxxxxxxx>]

On Fri, Dec 10, 1999 at 09:26:01AM -0600, wsuetholz@centonline.com wrote:
> I had forgotten where the problems had occured, I just noticed the 0x0D and 
> thought it was worth forwarding, I should have looked closer and seen that 
>they
> were talking about Opcodes.  I haven't looked at tn5250 recently, so I don't
> know if you are processing the 0x0D opcode or not.  It is newer than the spec
> that I used for doing my tn5250 emulator which doesn't process it currently.

Then I'm sure we're just ignoring it.  We just ignore any opcodes we don't 
understand, and that seems to work well as there are only a few opcodes which
really require some different processing than normal.

Of course, this is the area with aboslutely _no_ documentation.  Probably some
SNA guru might understand what they mean or why they're there ...

> 
> Just to make sure we are on the same page....
> 
>   Opcodes:  These are the things that they added to the 5250 datastream for
>             the telnet processing,  Basically something that is really part
>             of the SNA protocol level. 
> 
>   Commands: These are the 5250 Datastream High Level what to do..
>             Like Write, Read, Clear, Save, and Restore
>             Screen...  Save/Restore is kind of weird as it's an Opcode and
>             a command.  I've seen the Save with a Put/Get Opcode, and I've
>             also seen it with a Save Opcode,  Same goes for the Restore 
>Command.
> 
>   Orders:   These are really only used in WriteToDisplay type Commands AFAIK.

Yuppers.

> 
> Speaking of Saving and restoring the screen, did you or Mike Madore ever
> redesign tn5250 to not use local buffers, and instead send the necessary info
> to the host to redraw the screen?

Out of curiosity, why would we do that?

I just extended it in such a way to remove the 'limit' of local buffers for
the format table and display.  I thought the idea was pretty nifty, myself :)

> 
> Bill Suetholz
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