Comment by nostrademons | Hacker News Reader

Comment by nostrademons | Hacker News Reader

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It's interesting that you mention TCP/IP, because that's the most famous example of a technology that "works in practice, but not in theory". Take a look at Van Jacobsen's presentation on the history of ARPANET:

http://www.youtube.com/watch?v=oCZMoY3q2uM

Packet switching was "utter heresy" (20m in) when it was invented. It "wasn't a network, it was an inefficient way to use an existing network". And it almost collapsed 25 years after it was invented; the presenter is famous for inventing the modern TCP/IP congestion control that saved the Internet [1]. The TCP/IP flow congestion algorithm has been redesigned several times since [2]. It works not because it was designed well, but because it wasn't designed and instead evolved over many years with many contributions from people devoted to keeping it working.

Alan Kay is usually who I think of for great ideas that "work in theory, but not in practice". He's done some crucially important work in OOP, programming languages, and GUIs. But note that we don't actually use SmallTalk; instead we got C++ and Java. Nor do we use Dynabooks and Altos; instead, we got Microsoft Windows.

[1] http://en.wikipedia.org/wiki/Van_Jacobson#Career

[2] http://en.wikipedia.org/wiki/TCP_congestion-avoidance_algori...

Good points. We might be focusing on different evidence for good design. Certainly a system has to be tested -- the theory is not enough. But areas of TCP that were designed up front were things like being able to carry arbitrary payloads, including itself! This is what makes ssh and vpns possible. By contrast, many web protocols break when tunneling: soap within soap.

Also, for those unfamiliar with the actual process of protocol development back in those days, it was a wire protocol, which meant formal modeling and testing. Sure, it doesnt catch everything, but the web is far less formal. For example, the w3c originally said it wasn't going to provide an XML parser reference implementation because any graduate student should be able to code it up in two weeks. WTH?! While I don't doubt that is true, in practice it has meant that dozens of slightly different parsers were written, leading to hundreds of slightly different incompatibilities. Anyone who has had to integrate two different XML stacks will know.

I use Ruby, which was inspired by smalltalk; modern Java is also becoming much more functional.

In some ways, it has taken the larger community 20 years to understand Kay's vision. Also, he always said that the systems he worked on were prototypes -- he's commented before that he fully expected real-world systems to have surpased his long ago.

But now we have Ruby, Node and Rust. Even Java and Spring.io have dramatically reshaped things towards a "smalltalkish" future. So I still put a lot of weight behind some of Kay's observations of the industry.

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