[ntp:questions] NTPD concurrent clients limit
david at ex.djwhome.demon.co.uk.invalid
Fri Aug 1 07:19:04 UTC 2008
> Unruh wrote:
> "Those poor students come onto the lists asking questions and
> demonstrating that their knowledge level is low, but they are responsible
> to putting out the programs that will be used by thousands of people. "
> Unruh, Stop and think a moment, as fast as the electronics and software
> industry has gone, if you were a full-time student you still couldn't keep
The type of question that I believe he is thinking of often looks like a
college homework question and indicates a basic lack of understanding of
computer technology and how to find and understand fundamental source
documents (there may be some excuse for the latter in that Microsoft
documentation tends to lead you in circles around the details, never
reaching them and the ntpd RFCs are written for mathematicians, not
Companies should not be using such people without strong supervision.
Although I don't know whether it comes from using students, or simply
using people good at time and budgets, but lacking technical knowledge,
but a lot of commercial internet and web related implementations are
clearly done by people who didn't understand the basic philosophy behind
the protocols. For example Microsoft stick quotes round the human
friendly part of email addresses, because they are sometimes needed to
protect special characters. However the whole point of the design of
email addresses and email headers in general, is that they should look
reasonable when viewed as a memo header. As a consequence, the human
readable part is carefully specified such that, in normal usage, quotes
should not be used. There are also many travesties of web standards
around, which look like they were the result of untrained staff.
Microsoft made some significant, but conceptually simple, errors in
implementing SNTP in W32Time, one of which is now grand fathered in.
(Specifically, I'm thinking of hard coding the stratum at 2, and using
symmetric active instead of client request modes.)
Unruh's basic point, though, was that, if you buy an NTP implementation
and there is any possibility that it wasn't implemented from the
reference implementation code, it is very likely that it will contain
significant mis-implementations of the protocol and will almost
certainly considerably lag behind the current release information (which
lags behind the development branch that Dr Mills oversees).
In terms of failing to understand protocols. You are using the
(original) usenet interface to this forum, but it is actually gatewayed
to a mailing list. As a result, quite a few lookups are going to get
done on the xxx top level domain. Ignoring the forgery implications,
this concentrates excess traffic on a limited number of servers. I use
.invalid, which is specially allocated for the purpose of bogus domain
names, and, even if they don't actually do so, the root servers could
take steps to cause responses to be cached for a very long time. In any
case, there are proposals to allocate .xxx.
> up with the "progress" and changes. Consider the boy that started ebay, he
> cobbled up a bunch of canned scripts for lack of programming experience to
> get that thing going. I would say in the end his approach succeeded beyond
> his wildest dreams.
> We all get thrust into positions dealing with the relatively unknown, that's
But here we are only talking about things relatively unknown to us
personally, in which case the correct solution is to research them, but
what often happens is people try to get others to give them potted
answers to that research (usually without providing enough facts to
confirm that what is being asked is even a resonable approach to the
> how most of us learn and what eventually leads to innovation. That's also
The people we are talking about don't want to learn; they simply want an
answer to the current sub-problem.
> what got me into electronics in the first place, regardless of how smart you
> are, or what you know, you can never learn it all. The day you stop learning
> is the day you cease to exist.
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