[HECnet] DAP

[Paul Koning]

> On Dec 10, 2019, at 6:36 PM, Thomas DeBellis <tommytimesharing at gmail.com> wrote:
> 
> Interesting.
> 
> Do you have source for the DAP/NFT/FAL on Tops-10 or know where I might get what you have?
> 
> May I ask you what it does against a VMS system?  Unless it is reporting DAP 7, my guess is that it won't work.

Why would you say that?  The DECnet rule is backward compatibility, that's why the version numbers are exchanged.

Actually, DAP takes this very seriously indeed, which is why it sends very long bitmaps describing in detail all the protocol features supported.

It may well be that a V7 DAP implementation won't talk to V4 (Phase II).  But I'd be very surprised to see it fail talking to a V5.6 protocol peer -- I'm pretty sure RSTS uses that version and we would certainly have complained if other Phase IV implementations had trouble with that.

More in general, across the board the rule always was "One version back compatible".  So Phase IV can talk to Phase III (but not to Phase II -- except for PyDecnet.  :-)  )

	paul