[ih] Installed base momentum (was Re: Design choices in SMTP)

[Brian E Carpenter]

On 10-Feb-23 15:16, Jack Haverty via Internet-history wrote:
> On 2/9/23 14:57, Dave Crocker via Internet-history wrote:
>> Such is the lesson of installed base momentum.
> I agree - the installed base is a formidable obstacle to getting any
> kind of replacement propagated.   Stagnation and fragmentation into
> silos seems to be the result, as players introduce a desired new
> technology into just the components that they can control.
> 
> But I also wonder -- How did TCP overcome the momentum of the installed
> base?

Easy. It came for free with BSD Unix (and DEC Ultrix iirc) with a
full suite of applications. So it came on Sun, Silicon Graphics, Cray,
and there were X-terminals. There were cheap TCP/IP packages for PCs,
and Wollongong was reasonably priced for DEC/VMS. Everything else was
proprietary (SNA, Novell Netware, DECnet, etc.) or imaginary (OSI).

(IBM mainframes were a sticking point for a while.)

The timeframe was actually 1985-1990. The game was already over
by 1990, although it took another few years and the launch of
Mosaic and Netscape before management mainly realised it.

> 
> At the time, in the 1990ish timeframe, there was a huge installed base
> of network technology.   Hundreds of thousands of computers utilizing
> networks based on SNA, SPX, XNS, Decnet, etc. etc.   TCP existed, but
> was a small player, confined largely to the academic and research
> communities.

But we had an open network, and for most of the industry, that was still
a dream. It was interesting in the early 90s talking to the European IT
industry about what academia was doing - they simply couldn't understand
what we were talking about or why we wanted 34 Mbps international links,
when they thought 9600 baud was high speed.

> 
> But almost overnight, actually over just a few years, TCP became a real
> player, and then the dominant player, and by now all of the other
> technologies of that installed base have simply disappeared. The
> installed base of 1990 is gone without a trace.  Are there any computers
> anywhere still running those well-established technologies?   I haven't
> encountered any, but I wouldn't be surprised if some still existed.
> Perhaps something running Cobol somewhere.
> 
> So how did TCP manage to blast through that momentum of the installed
> base, creating such a chaos in the collision?   And how did it do it so
> rapidly?

Suppressed demand, I think, and expectations aroused by OSI hype. And
from 1995, the Web.

> 
> Curiously, that collision of TCP with the installed base involved TCP/IP
> V4.   TCP/IP V6 has come along and its been quite a few years in
> transition.   It seems that the momentum of the installed base of TCP/IP
> V4 has blunted the adoption of TCP/IP V6.   Why?  What's different?

We probably started IPv6 too soon, thinking very long term, so we over-
designed. But that long term process was also to some extent obviated
by the practical success of NAT, which took some of the urgency out of
deploying IPv6.

Google stats have IPv6 usage at 38% of the total now. Up a bit every
month.

https://www.ietf.org/archive/id/draft-ietf-v6ops-ipv6-deployment-10.html

> 
> A similar situation seems to exist in other network areas, e.g., the
> mechanisms of electronic mail that we've been discussing.  New
> technologies can get invented and documented, but often never get widely
> deployed.  Why?   What magic incantations were used to deploy TCP in the
> 1990s that have been apparently now lost.

Oh, I think it's an application by common consent of the adage
"If it ain't broke, don't fix it." Email isn't badly enough broken,
apparently.

    Brian

> 
> Perhaps some historian has some answers....
> 
> Jack