Do you have any orders currently in the Mt Gox dark pool?  Or since trading resumed after the security problem?

July 2. 

15.5 is the new 17.

My situation is not as bad as yours.  I have three nearly identical rigs and one of them, sometimes needs more than one power on/off sequence, and a reset, in order to properly recognize both GPU cards.  When I first set up these rigs I was mislead because the poclbm miners would start fine - no errors, but proceed to use all the CPU at a low hash rate.  I speculate that this is because the miners can recognize the CPU as a device and I speculate that somehow the CPU is emulating the GPU and running at a much lower MH/sec.

Eventually I used aticonfig to display the recognized adapters, and rebooted until they were all there.  As I mentioned in the post above, I use a UPS to avoid reboots. The miner rigs run for days, and I reboot them only to upgrade mining software for example.

I prefer the notion of conventional FOREX market to your use of real market. 

As many here know "painting the tape" by placing misleading buy and sell transactions, is illegal in regulated markets.  However, to the best of my knowledge, placing misleading open orders is not illegal, so long as those bluff orders are not actually filled to "paint the tape".

With today's HFT, i.e. high frequency trading techniques, and especially the ease with which algorithmic bots can be written for the Mt Gox trading API, its no surprise to see misleading open orders, that can be rapidly canceled - by say a bot, in advance of price movement in their direction. 

For example, a market gamer style bot could issue enough bluff bid orders to make it appear that there is a preponderance of inventory for sale.  Conventional technical analysis would suggest to the naive trader that prices should move lower to correct that inventory imbalance.  But the gamer bot simply wants to purchase a small lot of bitcoins are a lower price, then cancel the bluff orders below that price, and sell on the rebound back to the non-bluff inventory balance.

Would more active Mt Gox traders please respond as to whether Mt Gox currently has a dark pool available for open orders.  On another thread, someone said that all open orders currently on Mt Gox are visible.

Good question.  I intend to record historical open order information to analyse such phenomena.

I use linuxcoin.  Often the linux reboot command does not work for me, in that I get the same problem you report - a failure to detect the GPUs.  I have a UPS to prevent reboots due to power interruptions, and when I need to perform a reboot. I shut off the power at the power supply switch, restore the power, and if necessary, short the reset pins on my case-less motherboards.  This latter quirky step is required to ensure that the rig boots from the USB memory stick.

Thanks, I saved your samples and was not aware of the curl_setopt feature.

Understood.

Sorry that I misunderstood your objection to my statement. Apparently what I described as market spreads, you meant market stability. With that clarification, your point stands.  I have nothing to offer regarding market volatility in the face of zero commissions.

For others, the definition of market spread: http://www.investopedia.com/terms/m/marketmakerspread.asp
the definition of market volatility: http://www.investopedia.com/terms/v/volatility.asp

Why are you selling?

I don't have your experience, and please forgive that, but my research on FOREX shows that there is no central market that charges commissions. Rather FOREX, i.e. the foreign exchange market, is organized on a distributed basis between FOREX market makers.  Furthermore, FOREX operates as layers of peers, such that the innermost market has large banks as members that interchange large orders on very narrow spreads - and such that the outermost layer dealing with the public has more or less fixed percentage fees derived from the spreads charged by inner layer market makers.

If you agree with my characterization, then perhaps the bitcoin FOREX market will evolve in this direction, in which direct interaction between big players will sidestep commission-charging markets, e.g. Mt Gox - leading to yet another sort of FOREX free of centrally-charged commissions.

From the Mt Gox web site ...

Regarding my conclusion, see http://www.forextraders.com/forex-broker-tips/dealing-spreads-provide-incentives.html for a description of how market maker spreads are determined. 

Briefly, to conduct a profitable market making operation, the market maker places both a bid order and an ask order from their inventory.

(1) The price spread between these two orders must cover the market commissions - if any.  The market maker profits as buyers entering the market purchase at the ask price, and conversely sellers sell at market maker's bid price.  Assuming a typical transaction distribution of such buyers and sellers, market making is profitable. 

(2) Competition between market makers forces the spreads to the lowest profitable level. Thus, if a certain number of active Mt Gox traders have zero commissions, then their market making activity generally determines the spread. 

Therefore it is shown that zero commissions cause historically narrow spreads.

It has been suggested elsewhere that public interest in bitcoins are reported by Google Insight has recently declined. 

If public interest is a leading indicator of price, then that is an explanation.  On the other hand, public interest may be a coincident or lagging indicator because rapid bitcoin price increases are news that makes some people want to learn more about bitcoins.

When the Google Insight time series has enough ups and downs then we may be able to figure out the degree of predictability for bitcoin public interest as an indicator.

This works for me.  I am developing a Java client for the Mt Gox API and use the linux curl utility for testing.

The -v option gives a verbose trace of the HTTP protocol, and is not otherwise needed. The -k option ignores the Mt Gox SSL certificate checking - and should not be used in a production script.

For the next 25 days or so, certain traders affected directly by the Mt Gox rollback have zero commissions.  That accounts for the historically narrow spreads.

Bluff bid/ask orders attempt to manipulate the market by providing a false indicator to traders' and algorithms' depth-of-market decisions.  These are legal, and risk of actual order filling is reduced if a high-frequency algorithmic bot cancels the order in time.  On the other hand, actually placing orders to "paint the tape" may constitute illegal activity in regulated financial markets.  See http://en.wikipedia.org/wiki/Market_manipulation.

Your personal trading activity is stereotypical with regard to modern markets dominated by market-making algorithmic bots.  Such algorithms are not based upon emotions, i.e. greed and fear. Personal market making or day trading without the aid of a computer trading system is nowadays difficult. Of course there may be plenty of profit without a computer trading system - simply buy dips and hold, or even more simply - cost average bitcoin purchases and hold. 

See: http://en.wikipedia.org/wiki/Dollar_cost_averaging

What you call ROI is more correctly called operating income - which supports your point just fine.  Return on investment is all about return on capital invested. 

Agreed.  I may look back into it.  During the day or two I spent tuning the GPUs, I had some stability problems dropping the memory frequency and did not pursue that option, rather I concentrated on pushing the core clocks to the max.

Looking over my Mt Gox trade log, I do not see any single large transaction that caused the move.  Rather there are many small, almost random sized transactions on the way down and on the way partly back up.  Here is one of the larger ones that occurred shortly after the 16.65 level was breached ...

[mtgoxUSD 1309472003463345 2011-06-30T17:13:23.000-05:00 269.10395017@16.64001]

It would be a chance for certain market makers subject to the .3 % commission rate to make a profitable trade - given how relatively large the spike down was.  I suppose that once the swing began, existing bid limit orders were cancelled and moved lower thus drawing the price downward in the face of continuing market sales orders.  I do yet track Mt Gox open order issuance, matching and cancellation, but once that happens it will be easier to explain this sort of behavior - but only the point of ignoring open orders in the dark pool.

Modern trade execution prefers to break up a single large order into seemingly unrelated smaller chunks.  Even if executed from the dark pool to hide the order, trades become  public knowledge once matched.  Breaking up a such a trade is a tactic to out-game front-running algorithms. 

My rigs: 1.48 MH/s/watt + no AC cost
Your rigs: 1.60 MH/s/watt + maybe some AC cost

Clearly your rigs are more efficient.  My GPUs are overclocked, perhaps yours is not.  In any case, I had limited choices when purchasing my rigs and chose the Sapphire HD 5770 because of their low purchase cost for the MH/sec produced - by then the 5830's were gone.