Re: capacity v bandwidth

Jack Haverty via Internet-history <[email protected]> Sun, 31 May 2026 12:13:31 -0700
Newsgroups	gmane.culture.internet.history
Message-ID	<[email protected]>
Turning purple is a clear sign of psychological stress.   Vint's escort 
was probably contemplating the massive amount of paperwork required to 
document the incident, the disciplinary hearings that would follow, as 
well as considering what his or her new life would be like at the new 
assignment on one of the outer islands of the Aleutians.

I can only recall small bits of my own meeting experience.  I'm not even 
sure of where I was working at the time.   It may have been while I was 
at BBN, and involving a meeting somewhere in the metro DC area.  Or it 
may have been when I had a student job at the MIT Instrumentation Lab, 
where navigation systems were developed for use in Apollo and 
Minuteman.   Anyway, it was a long time ago, in the late 1960s or 1970s.

There was a meeting, and I was late for it.   I wasn't a participant 
giving a presentation, but more like a fly on the wall to learn about 
some project.  After getting through the check-in procedure in the 
Entrance (with security clearances it could take a while...), I went 
down a corridor, saw a meeting already in progress with a few dozen 
people, most of them around a large table engaged in intense debate.  I 
found a chair against the wall and quietly sat down.  No one noticed.

The discussion involved DIA and DCA, which apparently "don't work well 
together".  As a techie nerd, I had heard of DIA and DCA, but hadn't had 
any actual experience with them.  They were both part of IBM's technical 
architecture.   DIA was Document Interchange Architecture, and DCA was 
Document Content Architecture.  I could believe that they didn't work 
well together -- possibly designed by different committees or groups 
within IBM.

The discussion seemed to be focussed on comparing different scenarios, 
and predicting what would happen in each.  The main difference between 
scenarios was apparently associated with "new debts".  I thought perhaps 
the current topic had something to do with budgeting.  But someone 
mentioned "new debts per second", which seemed a little strange.  I 
could believe "per year" or "per quarter" would make sense for financial 
planning and decisions.  But "per second"!?

Finally someone put up a slide or document for some scenario.   I had 
heard what I expected to hear - "new debts".  But the slide revealed it 
was actually "nudets".  I realized the discussion had been about NUclear 
DETonations in different scenarios.  The "per second" part was 
frightening, which is probably why I still remember it.

I was clearly in the wrong meeting.  Here, DIA was Defense Intelligence 
Agency.  DCA was Defense Communications Agency. Nothing to do with IBM 
technology.

I quietly got up and left the room.

I learned that day that the world suffers from a serious shortage of 
acronyms.  IP addresses are easy, just make the numbers longer.  But 
TLAs have to be just three letters, and that's not enough to avoid 
conflicts and ambiguity.

/Jack Haverty


On 5/31/26 10:59, the keyboard of geoff goodfellow via Internet-history 
wrote:
> thanks vint! AND believe it or not (now that we know what the room was) it
> just so happens there is a "vintage" 1976(!) picture of the NMCC at
> https://en.wikipedia.org/wiki/National_Military_Command_Center
>
> yours truly is now wondering what a present day/"modern era" of it must
> look like... :)
>
> g
>
> On Sun, May 31, 2026 at 10:47 AM Vint Cerf <[email protected]> wrote:
>
>> Thanks for asking, Geoff.
>>
>> On my first day of work at ARPA (as it was then called in 1976), I had to
>> report to the Pentagon to pick up my DOD building pass. I went into the
>> River Entrance and the guard told me to take a seat. Not long after, a guy
>> came out of the bowels of the Pentagon, conferred with the guard who
>> pointed at me. The man came over to me and said something that I didn't
>> really hear [you all know I wear hearing aids ...] but assumed it was
>> something like "good morning" - so I nodded and he escorted me into one of
>> the corridors. Soon we encountered another guard (Marine, armed) and they
>> attached another badge. We continued deeper into the Pentagon, I picked up
>> additional badges on the way until we entered a very big space with a lot
>> of people with headsets, large displays, even larger displays on the walls.
>> I said "This looks pretty elaborate for a personnel office." My escort
>> looked startled, turned purple (no kidding!)
>>
>> "Aren't you Mr. Smith!!??" he said. "No, I'm Vint Cerf. I'm just here to
>> pick up my building pass."  My escort fell silent, whipped me around, said
>> not another word, marched me through the reverse path, shedding badges as
>> we went. I ended up back in the River Entrance. I had just inadvertently
>> visited the National Military Command Center. In all the years since,
>> despite my clearances, I have never returned to the NMCC!
>>
>> Vint Cerf
>>
>>
>> On Sun, May 31, 2026 at 12:53 PM the keyboard of geoff goodfellow via
>> Internet-history <[email protected]> wrote:
>>
>>> vint, any chance you would be willing to recount to the list what happened
>>> at the Pentagon on your first day at ARPA in 1976.. in how you mistakingly
>>> got mistook for someone else in the reception area.. and ended up being
>>> walked thru multiple levels of guarded "security" checkpoints and ended up
>>> in the "War Room" (or whatever it was) instead of the HR office (recalling
>>> that ARPA didn't have an HR office)?
>>>
>>> over the years yours truly has retold that story of yours -- that iirc you
>>> to related to us at a meeting or conference or something -- when people
>>> have said such-and-such a "security" breach thing was "fake"/"made up" and
>>> couldn't ever possibly have happened in real life (such as say the
>>> security
>>> breach incident in the 1997 movie "Contact" that resulted in deliberate
>>> sabotage) where someone "got/slipped through security"
>>>
>>> g
>>>
>>> On Sun, May 31, 2026 at 9:07 AM vinton cerf via Internet-history <
>>> [email protected]> wrote:
>>>
>>>> Yes, I left Stanford in July or August and started at ARPA in Sept 1976.
>>>>
>>>> V
>>>>
>>>> On Sun, May 31, 2026, 11:39 Lawrence Stewart via Internet-history <
>>>> [email protected]> wrote:
>>>>
>>>>> … Rummages around for information theory hat.
>>>>>
>>>>> I don’t think I am alone in holding that things with digital
>>> interfaces
>>>>> should say “bandwidth” and things with analog interfaces should say
>>>>> “capacity”.
>>>>>
>>>>> The Shannon-Hartley theorem is about the analog part of this.
>>>>>
>>>>> In the digital domain, I think almost everyone uses “bandwidth” to
>>> talk
>>>>> about peak available bits-per-second and “capacity” to talk about
>>> usable
>>>>> bits-per-second under certain loads, queuing policies, and the like.
>>>>>
>>>>> In the above, bandwidth is absolutely misused for digital circuits as
>>>>> compared to its analog meaning.  Capacity, unfortunately, has two
>>>> meanings
>>>>> and they get muddled all the time.
>>>>>
>>>>> Language evolves and non of this offends me.
>>>>>
>>>>> Regarding Vint at Stanford I arrived there in September 1976, and by
>>> the
>>>>> time I was corresponding with Vint about using Ron Crane’s VDH line
>>>> driver
>>>>> to get SU-ISL connected to the SUMEX IMP, he was back in Washington I
>>>> think.
>>>>> -L
>>>>>
>>>>>
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>>
>> --
>> After July 1, Please send any postal/overnight deliveries to:
>> Vint Cerf
>> 1435 Woodhurst Blvd
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>>
>> Until July 1, send postal/overnight deliveries to:
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>>
>>

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