What had happened to Gareth Nelson? Is he in trouble too? He was the brain/algorithms guy behind the operation. He really seemed a very reasonable fellow. I was under impression that as an introvert he had to associate himself with some extroverts to deal with PR and other "people" tasks.

Battery-operated low-power consumer electronics aren't really relevant to mining hardware which is high-power application that pushes itself to the edge of death: either thermal from overclocking or starvation from undervolting.
Good. Analog and mixed-signal design flow is the way to go. Now please get back with your engineers and post some results of your preliminary simulations. E.g. which version of BSIM did you use? You could post some fragmentary results without disclosing the entire design.

This board has enough people that will understand such posts. And disclosing some technical data (even incomplete) will be the quickest way to distinguish you from all the previous scammers who only had marketroids at the ready and literally nobody to back them up on the technical front.

It looks like you are looking for a project to do on your miner.

In that case the sensible task is to modify the flash image:
1) boot with all file systems read-only
2) remount the fs read-write before the reconfiguration
3) remount the fs back to read-only after executing the configuration change
4) reconfigure syslogd (and other daemons) for logging to an external log concentrator
5) run the mining controller/concentrator on the UPS

Not only your flash storage will never be get corrupted but also you'll greatly increase its durability.

Obviously on Bitcointalk there always will be a sub-segment that treat coin mining as a status symbol.

For those I always advocate to look up the appropriate solution developed for audiophiles.

Edit: apcupsd and other UPS-communicating software only make technical sense when running on a server-grade hardware with error-correcting memory and the related processor circuitry fully supporting machine-check exceptions and recovery. Unless you change the controller in your miner that isn't the case. You'll just alter the failure modes and somewhat skew the probabilities of failures in your mining farm.

Edit2: I don't want to bump the thread: If you are really into running a mining farm on the UPS (e.g. you've already paid for it and cannot change the setup) then the proper tool to run is http://en.wikipedia.org/wiki/Network_UPS_Tools , which have both APC interface as well as support multiple devices per UPS and multiple UPS-es. N.U.T. also supports trivial UPS-ing via the cli: ssh/rlogin/telnet to each device and execute shutdown/poweroff/halt/telinit/whatever-else.

UPS-es are bad surge protectors. Firstly they have higher internal power loses than a dedicated surge protector. Secondly they exacerbate small power surges (I'm speaking of the cheap "line-interactive" UPS-es, not the premium "dual-conversion" UPS-es).

Mining hardware doesn't require a UPS. The only time it writes anything to its file system is when you reconfigure it. At all other times it is pointless to run miner on a UPS, by design miner doesn't remember anything for longer than some seconds or half a minute at most.

Even if your UPS is already a paid for capital expense your operating expenses will be lower if you run your miner bypassing the UPS, because no UPS is 100% efficient.

Some smart Icelanders finally did the correct calculations and started offering professional coin miner hosting with electricity hookups that are explicitly free of UPS-es and backup generators. Smart private miners were doing that since the beginning of Bitcoin mining.

In case this wasn't a rhetorical question. It is a manufacturing and maintainability aid. It allows things to be assembled and/or repaired by the folks that have no understanding of electronics. It is a typical requirement for military designs where the maintainer may be a soldier who explicitly is not supposed to know how and why his electronics work.

Thanks for your comment. Now that I recall that you use large shared heat-sinks I could also imagine that the pattern I see is a simple hex-tile to optimize the heat dissipation. I just couldn't see it on the PCB photograph alone. I forgot what's the gain from hexagonal tilling: sqrt(2)/sqrt(3)?

So can you tell us what is the motivation for the unusual design approach:

1) easier to simulate the mini-circuit
2) RF design to minimize reflection and noise in the traces
3) pick&place machine speed optimization or other manufacturability concerns
4) all of the above

The contrast to something like Enterpoint's quad FPGA board is obvious.

I have to ask: the main boards look mechanically designed to be cut/punched into 15 separate mini-boards. Are they indeed designed like so electrically?

Or maybe answering the above question will violate some of your non-disclosures?

Regretfully (or thankfully, depending on your point of view) this isn't the case. There's a lot of supposedly very new software and hardware that uses short (16- and 32-bit) timestamps. Off the top of my head: in the ATSC & DVB TV standards, lots of physical security hardware/software systems, countless price-sensitive embedded systems (including medical).

Edit: especially the medical field is notorious for implicit and explicit "expiration date"s. They've been using this concept for quite a while now, e.g. by giving expiration dates to completely stable chemical compounds.

This has already been discussed/dealt with. The timestamp field is meant to be "unsigned int32_t" which gives us additional over fifty years to ponder the proper way to hard fork.

For comparison, Unix time_t has to be signed to remain compatible with the existing programs that compute time differences.

Edit: Whatever you come up with, please do not leave it "undefined". Some jokers will put "This program cannot be run in DOS mode" there to create panic amongst Windows antivirus users. Luke-jr will probably put some prayers into them. Please just demand them to be zeros.

Your power factor is less than optimal, that is less than one.

http://en.wikipedia.org/wiki/Power_factor

This type of argument is why plastic bags in the USA had the following warning: To avoid danger of suffocation, keep this plastic bag away from babies and children. The plastic bag could block nose and mouth and prevent breathing. This bag is not a toy.

Just take away the external metal casing. Flip the machine on its side. Borrow a good centrifugal "air mover" from a neighborhood water damage repair contractor and some baffling that they use to direct the air. Also borrow a contact-less thermometer to understand the why the SP10 casing is badly designed for cooling and creates unnecessary temperature gradients. I don't know if Spondoolies' firmware has a "seized fan" shutdown programmed in, so you'll have to experiment with which fans can be removed.

The alternative is just to dress in your best cold weather clothes and photograph yourself near your Spondoolies' machines. You'll have a nice memento.

I haven't used Spondoolies' hardware personally, but I do have relevant experience of restarting bankrupt batch data processing facilities filled out with racks of 1U and 2U hardware from Dell and Sun. It had the same symptoms: the bottom was getting hot and the intake air had to be really cool. Neither Dell nor Sun field service technicians were giving us any trouble after seeing our temporary facility w.r.t. warranties and service contracts. We've actually lowered the rate of faults due to seized fans and accumulation of dust and debris. Only hard drive failures had increased.

I have to partially agree with the above. It does take some effort from skilled technicians. I'm not really familiar with the money saved in my case, it reduced the cost somewhere between 2 and 4 times.

Same about the warehouse, but I wouldn't call it "big" but "tall" and "thick walled". You may be able to operate mostly with natural convection and thermal inertia from the daily temperature oscillations.

Exactly. You not only don't need uninterruptible power, you'll be better of buying cheap, explicitly interruptible power from the utility company using special industrial/agricultural/pumping tariffs. I even dare to say that air-conditioning is an overkill, good airflow (which for SP10 means getting rid of the cases) and maybe cheap, evaporative cooling will be good enough. Get a small UPS to have a continuous network connection just for the local switches/routers and security cameras.

Or just admit to yourself that you've got your Bitcoin mining hardware as a status symbol.

Thanks. Could you ask them why they used TOGGLE_RATE 0.2? For SHA-256 TOGGLE_RATE should be 50%, this is pretty much a design goal for any one-way hash function.

Edit: Bonus question: Ask them how they calibrate/characterize the temperature sensors. IIRC your temperature sensors are intentionally low-resolution: something like 10C,20C,30C,... What is the achieved accuracy of step-crossing temperature for your existing chips that were already manufactured?

Last time I looked into the Satoshi client code it either ignored or de-prioritized peers listening on a non-default port.

Thank you very much for your succinct explanation.

Indeed, the security device I've seen (nothing related to Bitcoin) was designed for use on a nearly every day, and the charging period was shorter because the device was completely enclosed during recharge/data exchange.

How about supercapacitor instead of the rechargeable battery? Would that meet your goals?

And just to wrap it all up for both US and non-US readers I've accidentally found a nice short link showing pretty much all modern configurations available around the globe:

http://www.ccontrolsys.com/w/Electrical_Service_Types_and_Voltages
http://www.ccontrolsys.com/w/Four_Wire_Delta_Circuits
http://www.ccontrolsys.com/w/Three-Phase_Grounded_Delta_Circuits

I just noticed that you now have 6 terraminers instead of 5 in the original post.

Then another cheaper option is to get 240V 3-phase 3-wire with an additional electric meter. 6 miners will form a sufficiently symmetric load that won't require the neutral wire.

But you clearly will need help of an electrician and cooperation from the utility.


Those are the types of service that an example US electrical utility offers that do not require negotiation, just a matter of ordering and waiting for provisioning.