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Posted by timothy

+ - DOW drop, arbitrage and automated trading systems

Submitted by
Arun Jacob
Arun Jacob writes "On Feb 27, the Dow Jones Industrial Average (DJIA) dropped 540 points. In this 540, there was a 200 point-drop in a split-second that is attributed to problems with the Dow Jones data systems. Due to the record volumes, the DJIA re-calculation system could not keep up with the flood of orders and the DJIA value shown on tickers was 70 minutes behind the actual values. This was auto-detected just before 3 PM, when backup systems kicked in and updated to the real value in a split-second creating a 200 point cliff. This event itself had been reported on Slashdot previously.

Roger Ehrenberg, the former CEO of Deutsche Bank Advisors LLC and an ex-MD at Citibank analysed in a blog post the arbitrage opportunities that would have come up during the mismatch between the real DJIA and displayed DJIA. He points to automated programs doing statistical arbitrage that would have been able to notice the discrepancy and trade to take advantage.

Since quite a few of the brightest techies are writing pricing/risk/trading engines on Wall Street, can we get a feel from Slashdotters on the extent of automated trading programs out there? What is the scope of their algorithmic trading? Also, do these systems run on typical Unix systems, and what is the nature of experience of the techies who would code these systems?"

Comment: Re:copy-on-write (Score 2, Informative) 351

by MotownAvi (#17285540) Attached to: ZFS Shows Up in New Leopard Build
Why? In today's world, writing to an mmap-ed file most certainly doesn't hit the disk for each write. Instead, a block of memory from the buffer cache is used to hold the changes. The only difference is that instead of being backed (VM-wise) by the swap file, the block is backed by the mmap-ed file.

There's no real change here for ZFS, and it's unlikely that anything at the memory cache level even knows about the copy-on-write-ness of ZFS (or even cares).

