[ih] 'internet' and "Internet"

[Jack Haverty]

On 8/7/23 17:55, John Levine via Internet-history wrote:
> In principle there could be
> multiple disjoint internets but we succeeded beyond our wildest dreams
> and in practice it's all one internet or Internet.

In reality, there definitely were multiple disjoint internets.   I was 
involved in running one of them about 30 years ago.  We were not alone.  
It was straightforward for a corporation to build its internal internet 
(aka "intranet"), and keep it physically separate from the Internet.   
We managed our own address space and other administrative matters 
separately from the Internet administration.   Various constrained 
interconnects, such as gateway machines for mail traffic or web servers, 
were used as needed.   To "the Internet" we looked like a single machine.

But I don't know what is "practice" today.   Do corporations still have 
their own private internets?   Or have they actually all migrated to the 
Internet and somehow addressed all of the security concerns?   How did 
they get from there (private internets) to here (everyone on the 
Internet)?  In practice is everyone really on the Internet today?

Hope I got the capitalization right.....

Jack