[ih] vm vs. memory

[Bernie Cosell]

On 25 Oct 2017 at 13:40, Brian E Carpenter wrote:

> On 25/10/2017 13:13, Paul Vixie wrote:
> ...
> > Neither the Internet nor the DNS can be stopped and restarted, nor
> upgraded
> > as a whole unit.  New features must always be introduced in a way that
> is
> > backward compatible and thus ``roll out'' incrementally. 
> 
> +1e6
> 
> (Which is why we need to understand history.)

I first learned that with the ARPANET IMP code.  Before that, the systems 
I worked on could be taken down in the middle of the and new things 
tested, and then the old system put back if necessary.  With the ARPAnet, 
there was almost no time, day or night, that the IMPs could go offline.  
We quickly learned that something had to change, it was in three steps: 
1) put in code that handled the old way AND the new way [and of course, 
figured out which was which].  2) distribute code to switch over to the 
new way [could be done a few systems at a time to limit the damage if 
something went wrong], 3) take out the old-way code.  I can't imagine how 
you'd do something like that in today's internet, where noone has control 
over everything and so there's no way to get *anyone* to change their 
code [if they even can]

I think I only crashed the ARPAnet once [or maybe twice] with a buggy 
patch... sigh..

/Bernie\

-- 
Bernie Cosell                     Fantasy Farm Fibers
mailto:bernie at fantasyfarm.com     Pearisburg, VA
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