[erlang-questions] Lets build a stock exchange!

Joel Reymont <>
Thu Nov 15 14:34:48 CET 2007

On Nov 15, 2007, at 12:55 PM, G Bulmer wrote:
>>> (I realise your focus
>>> is a book, but wouldn't you like millions of people to use the
>>> software?).

No, I wouldn't. The software I will create for the book is just  
educational software. I will use this software to demonstrate Erlang  
features and to try to build a huge EC2 cluster.

I will likely develop the software for millions of people to use after  
I write the book. It will be a commercial effort based on the concepts  
described in the book. I don't think it's possible or viable to  
develop production software and write a book about this software at  
the same time. There's not enough time or pages in the book to  
accomplish such a feat.

>> Further, I am not sure how low the latency will be; I can't ping  
>> amazon, but when I ping google I get round-trip averages over 50 mSec

I think latency here is the delay introduced by the software itself,  
not the delay introduced by the internet.

> My problem is I don't see why *I* would run a stock exchange  
> application, so I don't see why *I* would run Amazon EC2 instances.

You don't need to run a stock exchange application. You may want to  
add your instance to the cluster to take part in the Erlang  
scalability test.

> On the other hand, I do see why I and others might want to run EC2  
> instances for auctions.
> A plausible explanation for why I'd run the stock exchange  
> application would help me a lot.

Writing a book is a marketing venture with an element of teaching. It  
helps to be passionate about the subject one is writing about. I'm not  
passionate about auctions but I am passionate about all things  
trading. I don't want to sell books or have a need to. I do, on the  
other hand, want to show that Erlang is a good fit for high- 
availability financial apps. This is my focus.

> Adjusting resources by starting and stopping EC2 instances also  
> seems to be a reasonable fit to auctions. Having a 'hub' which  
> contains the product catalogue would seem to be an enabler for the  
> whole system, and separate EC2 instances would be used for auctions  
> (with some 'low-rent' instances for low-activity auctions).

I'm putting together all the feedback that I received so far and  
trying to organize it into a table of contents. The book is turning  
out to be quite thick. May I suggest that you take up a parallel  
effort and describe how to build auctions on EC2 in a series of blog  
posts? The software you develop will be commercially viable and useful  
to you. It will serve as additional proof of viability of Erlang on EC2.

	Thanks, Joel


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