It is my understanding that at least Eligius pool isn't a "honest node" and intentionally produces acausal blocks (or at least as close to acausal as they deem practical).

If I remember correctly it integrates the error over 2016 time intervals. This is some approximation of PI, more accurate approximation would be if the calculation for the expected block time was carried since the block 0 (time = -infinity).

Due to the esotheric block timekeeping the typical discrete-time transformation cannot be applied. If I remember correctly the block chain can be extended by a block up to two hours in the past. Because of that process under control is marginally acausal. This esotheric timekeeping precludes use of any standard mathematical tool from the theory of control systems.

So if you wanted to implement a discrete time approximation of P controller, you would measure the error over a single interblock interval. In case of non-monotonic block time you would have to set difficulty to some negative number.

PID, PI and P are terms from the the theory of Linear Time-Invariant systems and pretty much nobody deals with acausal systems. I agree that PID controllers are not that difficult to fine tune. But any tool (theorethic or practical) do do such tuning assumes causality. Moreover, the PID controller design with discrete time but variable time step are quite complex mathematically.

If the block time was changed from the current esotheric one to something which is monotonically increasing (like NTP time), then the change in the difficulty feedback loop could be considered and implemented with safety.

I have a semi-constructive suggestion:

Anyone proposing a change in the feedback controller for difficulty should be required to show the stability region of his proposal. Pretty much everyone who tries to "improve" the PI controller implemented by Satoshi comes up with some hackneyed version of PID controller and then is surprised that it can be made to osciallte and is not even assymptotically stable in the Lyapunov sense if any nonlinearity is included.

http://en.wikipedia.org/wiki/Lyapunov_stability
http://en.wikipedia.org/wiki/PID_controller

I may have some software engineering disagreement with some of the Satoshi's choices, but the choice of PI regulator to adjust the difficulty is an example of excellent engineering: PI-s may be slow, but they are absolutely stable for every causal process and for every error signal.

I want to belive you and yet my experience tells me that there's something fishy here.

Run-from-flash on a cache-less ARM is definitely possible but also definitely very slow. It may be OK for driving a modem, but most likely it will not be OK for any real crypto application.

As far as I know, the SSL and TCP/IP implementations sold by Verifone (licensed from Windriver?) are seriously crippled by implementing only minimal subsets of the full functionality, suitable to run only on LANs or WLANs with low packet loss.

If the whole project get from the start rearchitectured to dumb-wimpy-client/smart-ruddy-server that would increase the chances of achieving something that is both deliverable and maintainable in case of the future need for modifications.

Admittently I don't have an actual experience with Verifone's hardware, but we had to deal with something very similar. In the end the acceptable and secure solution required about 5-15 seconds wait to respond to the keypresses. And  this was after immense time spent optimizing the C code with hand-crafted assembly.

I just downloaded some random pdf book full of blurbage from Verifone Devnet. Here's what I read there:
Is it 3, 4 or 6? And how much of that is left for the application to use?

In light of the above the whole project looks science-fiction-ey to me.

For the benefit of the readers who never visited the USA:

Bounty is the market-leading brand of the clothes-dryer sheets.

Cute joke, but somewhat inside-ry.

I think those are the transaction fees that are available in that block but unclaimed by the miner.

Well, bittorrent was an inclusionary protocol. Bitcoin is the opposite: explicit exclusionary protocol.

Anyway, I just checked the blame on lines 1297 down to 1307:

https://github.com/bitcoin/bitcoin/blame/master/src/main.cpp

Gavin Andresen had wisely ceded the signature control over checkpoints to fabianhjr. Hopefully Fabian resides in a country that doesn't have an adversarial legal system.

I'm going to side with ArtForz and his idea of built-in SNTP for the Windows version of bitcoin. The native Windows NTP works well only in domains. For the regular Windows boxes that are just members of a workgroup there are multiple problems. Majority of those problems are caused by the various add-ons, but I don't know how many people run just bare Windows machines with software only from Microsoft.

The code to properly query the Windows Time Service would be more complex than just a simplest generic SNTP code.

No, bankrupt like Linus Torvalds in his dorm room. If you have an access to the typical news retrieval service search for that quote from Balmer about Linux. He said that on a conference call with investment managers and had a very nice explanation followed by a nice discussion. It really explains how open-source positioning changes the financial performance of securities.

Yeah, the bitcoin economy is still in the testnet phase. If I may borrow a Linux phrase from Steve Balmer, "Bitcoin, in a way, launched bankrupt." So you just can't apply your usual metric. It will get ripe when the first audited financial reports come out of the Bitcoin economy.

Not enough finance professional involvement yet. Various Bitcoin-related business entities are only just getting formed. Its not yet ripe for the real interest.

I apologise for the misrepresentation. I misunderstood somebody's else description. I never looked at the 0.3.24 code. I went straight from 0.3.23 to 0.4rc2. Sorry.

Sorry, no. Please compare 0.3.24 to 0.3.23. The example of the bug:
You have 10.0007 in the wallet and configure it to pay 0.0005 fee. You send 10 plus 0.0005 fee
and expect the wallet to retain the remaining 0.0002. Psych! It went to the miners and your wallet is empty.

The "serious" part mostly pertains to the "conspiracy" part. Traditionally, charges of conspiracy were made when the people involved modified the off-the-shelf accounting software. When "off-the-shelf" really means "off-the-sourceforge" the conspiracy charges are an easy add-on for the plaintiff lawyers.

Mining pools mostly. Out of the top 10 is there any that doesn't skim or is upfront about the fact that it skims the "means to assure the security of the network transactions".

Also, to the lesser extent, the clients with a bug "change is to small to return it to the wallet, so send it to the miners." It was re-introduced in 0.3.24, which is the current official one.

It also pertains to you:
What if your or ShadowOfHarbinger's software were used to run somebody's else business? You can eat your own fees just fine, but if you make someone else "eat fees" that is somewhere between "negligent accounting" and "conspiracy to commit fraud in accounting". The last one is when someone modifies the software that handles the transactions. In bitcoin ecosystem pretty much everyone runs modified software, so lawyers will have a field day in wringing the settlements from the naive programmers and business-people who hired them.

3) Lawyers have sufficient income from other sources. The bitcoin targets are not yet ripe enough. By "ripe" I mean that nobody yet signed off on their audits as "true & correct". Once the word gets out among the lawyers that bitcoin-using businesses routinely sign off the perjurous audits that don't follow the GAAP the writs will start flying.

Well, I apologise for being presumptious about your personal involvement in the fee-skimming scam. Its my personal bias I'm getting from the bitcoin promoters that I personally met.

As to who is bat-shit crazy it will be probably for the courts to decide. This pertains especially to those developers who reside in the USA and other coutries with an adversarial legal system. The various fee-skimming scams are just such an juicy target for a class action lawsuit in the Eastern Texas Circuit that somebody there will just grab this opportunity.

It either that or bitcoin will tank so low that not even a bottom-feeding lawyer will be willing to get out of the bed.

Famous last words. Garbage collecting stale locks on the wallet is a nice gig, you'll spend endless nights debugging it.

kjj probably runs a mining pool which collects those fees and doesn't distribute them to the actual miners. So your cost will be his gain.

Isn't the bitcoin ecosystem wonderfully egalitarian that way?

A huge majority of internet routers use NTP. A huge majority of the long distance synchronous optical links use GPS to synchronize clocks. To use the IP protocol is essentially to trust in the US Goverment.

Any sufficiently self-deluded internet cryptoanarchist is indistinguishable from a crackpot.

The un-deluded cryptoanarchist would probably research how to transmit bitcoin over shortwave radio. Or better yet, use VHF/UHF moon bounce (EME). It is the only way to be safe.