Re: Upcoming time boundary events

On 2025-05-30, Arne Vajhøj <arne@vajhoej.dk> wrote:

On 5/30/2025 8:18 AM, Simon Clubley wrote:

On 2025-05-29, David Wade <g4ugm@dave.invalid> wrote:

On 5/27/2025 8:15 AM, Simon Clubley wrote:

These old protocols have a habit of staying around a lot longer than
expected. For example, I suspect somewhere people are still using UUCP,
2780/3780, xmodem, DDCMP, original SNA (not SNA over TCP/IP), etc, ...

>
SNA is an architecture. SNA over IP is still SNA. In fact 3270 over
BiSync can be part of an SNA Network. Would you include SNA over X.25?
>

 
I look at SNA in the same way as I look at DECnet. At one time, DECnet
ran over its own transport and lower-level protocols. As a result of
a changing world, it was then adapted to run over a protocol (IP) which
is not a part of SNA/DECnet.

>
Isn't DNA the equivalent of SNA?
>

For me, the split point between original and current SNA/DECnet occurred
when the previously fully native implementation was adapted to run

over IP.
>
Isn't it more accurate to say that support for IP was added as a
possibility in parallel with still supporting the other protocols?
>

It's much more than that. What matters here is that this is the point
there was a distinct culture change with both DECnet and SNA.

Up to this point the general feeling among many people (inside both
IBM/DEC and customers alike) was that their own protocols were superior
to "that IP stack stuff" and that you didn't need IP.

The need to enable your own vendor-specific network stack to run over
the IP stack was the point at which you had to change that attitude
forever and that those vendor-specific protocols now needed to work
with an industry-standard protocol that the vendor did not control.

In case anyone here has forgotten this, I draw your attention to the
early days of UCX and how DEC was dragged into the TCP/IP world against
its will. With what other vendor would an ongoing market exist for
a third-party TCP/IP stack that you had to pay for ?

Simon.

--
Simon Clubley, clubley@remove_me.eisner.decus.org-Earth.UFP
Walking destinations on a map are further away than they appear.