thanks Michael, very useful,<br><br>Michel<br><br><div class="gmail_quote">On Tue, May 10, 2011 at 3:49 PM, Michael Mehaffy <span dir="ltr"><<a href="mailto:michael.mehaffy@gmail.com">michael.mehaffy@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">Michel,<div><br></div><div>Yes, "design patterns" is Alexander's pattern language applied to software. (This writer mistakenly applies it more generically to patterns as in pattern books, which was only one aspect of Alexander's (and the software engineers') thinking - and not the most crucial aspect, which was the network logic.</div>
<div><br></div><div>Interestingly, the book author applies design patterns post facto to the development of computer networks - looks very interesting.</div><div><br></div><div>By the way, Google "design patterns" and you get 3 million hits. Google "pattern language" and you get 400,000 hits - about an 8 to 1 ratio. The architects did something wrong... (Hint: open source!)</div>
<div><br></div><div>Here is the correct history, listed accurately in the Wikipedia entry for Design Patterns:</div><div><br></div><div><span style="font-size: 13px; line-height: 19px; font-family: sans-serif;"><h2 style="color: black; font-weight: normal; margin: 0px 0px 0.6em; overflow: hidden; padding-top: 0.5em; padding-bottom: 0.17em; border-bottom: 1px solid rgb(170, 170, 170); width: auto; font-size: 19px;">
<span>History</span></h2><p style="margin: 0.4em 0px 0.5em; line-height: 1.5em;">Patterns originated as an <a href="http://en.wikipedia.org/wiki/Pattern_%28architecture%29" title="Pattern (architecture)" style="text-decoration: none; color: rgb(6, 69, 173);" target="_blank">architectural concept</a> by <a href="http://en.wikipedia.org/wiki/Christopher_Alexander" title="Christopher Alexander" style="text-decoration: none; color: rgb(6, 69, 173);" target="_blank">Christopher Alexander</a> (1977/79). In 1987, <a href="http://en.wikipedia.org/wiki/Kent_Beck" title="Kent Beck" style="text-decoration: none; color: rgb(6, 69, 173);" target="_blank">Kent Beck</a> and <a href="http://en.wikipedia.org/wiki/Ward_Cunningham" title="Ward Cunningham" style="text-decoration: none; color: rgb(6, 69, 173);" target="_blank">Ward Cunningham</a> began experimenting with the idea of applying patterns to <a href="http://en.wikipedia.org/wiki/Programming" title="Programming" style="text-decoration: underline; color: rgb(6, 69, 173);" target="_blank">programming</a> and presented their results at the <a href="http://en.wikipedia.org/wiki/OOPSLA" title="OOPSLA" style="text-decoration: none; color: rgb(6, 69, 173);" target="_blank">OOPSLA</a> conference that year.<sup style="line-height: 1em; font-weight: normal; font-style: normal;"><a href="http://en.wikipedia.org/wiki/Design_pattern_%28computer_science%29#cite_note-Smith1987-1" style="text-decoration: none; color: rgb(6, 69, 173); white-space: nowrap;" target="_blank"><span>[</span>2<span>]</span></a></sup><sup style="line-height: 1em; font-weight: normal; font-style: normal;"><a href="http://en.wikipedia.org/wiki/Design_pattern_%28computer_science%29#cite_note-Beck1987-2" style="text-decoration: none; color: rgb(6, 69, 173); white-space: nowrap;" target="_blank"><span>[</span>3<span>]</span></a></sup> In the following years, Beck, Cunningham and others followed up on this work.</p>
</span><div><br></div><div>p.s. One of the spinoffs was a little device Ward developed to work on the patterns collaboratively over the Internet - a little thing called Wiki. You've heard of it?!</div><div><br></div>
<div>Cheers, m</div><div><br></div><br><div class="gmail_quote"><div><div></div><div class="h5">On Tue, May 10, 2011 at 8:23 AM, Michel Bauwens <span dir="ltr"><<a href="mailto:michelsub2004@gmail.com" target="_blank">michelsub2004@gmail.com</a>></span> wrote:<br>
</div></div><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"><div><div></div><div class="h5">any relation with Alexander's work?<br><br>
see:<br><br><h1>Patterns in Network
Architecture</h1>
<h3>From P2P Foundation</h3>
<div>
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<p><b>* Book: Patterns in Network Architecture: A Return to
Fundamentals, by John Day, ISBN-10: 0132252422, ISBN-13: 9780132252423,
Prentice Hall, 2007.</b>
</p><p>URL = <a href="http://www.informit.com/store/product.aspx?isbn=0132252422" target="_blank">http://www.informit.com/store/product.aspx?isbn=0132252422</a>
</p><p><br>
</p>
<h1><span>[<a href="http://p2pfoundation.net/Patterns_in_Network_Architecture?title=Patterns_in_Network_Architecture&action=edit&section=1" title="Edit section: Review" target="_blank">edit</a>]</span> <span>Review</span></h1>
<p>Jon Crowcroft:
</p><p>"It isn't every day (pun intended) that one of the true Old Guard
writes and publishes a book, and it behooves us to take notice. In this
case, the author's expertise and his subject matter are of particular
timeliness, because of the worldwide resurgence of activities with
regard to next-generation network architectures, that is, a replacement,
or upgrade to the Internet (dare one say "Internet 2.0"?).
</p><p>John Day is a well-known scholar of historical cartography, and
this book, in a way, is a roadmap of network architecture. The roadmap
starts back in 1970, tracing from the roots of connectionless
packet-switched dynamically routed systems such as Cyclades, and the
ARPANET, through to recent discussions on multihoming, multicast, and
mobility, with a view along the way of naming, addressing, protocol
stack design, protocol design, and concepts of layering.
</p><p>That description makes the book sound fairly standard in terms of
structure and content, but it isn't. The book includes many discursive
elements whose intent is to provide a collection of patterns. Design
patterns originated in the building trade as a way for crafts people to
pass on successful methods of construction (in the sense of affordable
and noncollapsing) to less-inventive people (or people who want to spend
their inventive efforts in different areas). Software engineers picked
up on this idea, applying the techniques in both the microscopic world:
patterns allow you to decide what algorithm is applicable in solving a
problem in the small; and the macroscopic world: architectural patterns
allow you to decide on an approach to breaking down a large system into
the right kind of components.
</p><p>Essentially, this book does the same thing, at the protocol stack
level, and at the system level, with a collection of historical and
contemporary examples to support the arguments.
</p><p>The book makes interesting reading, especially as it represents a
fair balance in reporting the early ideas that came not just from the
United States, and restates the importance of the Opens Systems
Interconnection (OSI) model (not the ISO protocols) in understanding
layering and beads-on-a-string, as well as reasserting the use of the
model in clarifying the perennially confusing concepts of names,
addresses, and routes.
</p><p>The book begins with a discussion of seven principles that
emerged through the early history of networking (I won't spoil the book
for readers by listing them here), and ends in the tenth and final
chapter, entitled "Backing Out of a Blind Alley," with an appeal to
fundamentals. Essentially, the author points out that researchers
(especially academics) are strongly motivated to keep moving on with
claims of ever-newer tricks, but rarely to consolidate these tricks into
a set of principles that stand for a long time (because then they would
have to completely change the topic of their research). Thus uncovering
a foundational theory of networking would put a whole generation of
networkers out of work (or funding at least).
</p><p>The book is peppered (saltily) with fine quotes and fascinating
asides from philosophy (for this reader, especially, the Chinese
diversions were most novel and illuminating). Illustrative of the range
is that one finds Wittgenstein and Dave Clark, Confucius, and Dr.
Seuss—Frege's useful reminder that "The sign '=' should be read as 'is
easily confused with'" would make an excellent IETF T-shirt.
</p>I found the book extremely readable and enjoyable, and although I
might argue with some of the opinions in the book, I think that this is
just more evidence that I should recommend the book to anyone
interested in knowing why we are where we are in networking, and being
better informed about where we should go next."<br clear="all"><br>-- <br>P2P Foundation: <a href="http://p2pfoundation.net" target="_blank">http://p2pfoundation.net</a> - <a href="http://blog.p2pfoundation.net" target="_blank">http://blog.p2pfoundation.net</a> <br>
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