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61  Other / Beginners & Help / Re: Submersing a rig on: January 26, 2012, 01:15:59 AM
Ok so how about this. Take a 44 gallon drum and flow the water in/out, pressurize it. Weld a metal well into the drum to seat the GPUs in an oil bath. The welding would be a little more fiddly and you would want to give it a good hydrostatic test but there is no reason you couldn't do it length ways with the drum on its side. You could also weld fins onto the bottom of the well to maximize surface area.

I see no reason why that wouldnt work, but boy, sure sounds a lot more complicated than buying a $40 oil cooler. In either scenario you still need tubing, a pump, oil container etc. It would also take up even more space in my shed for no apparent advantage. Perhaps if you have a water source and no filter or pumps to use, then your approach might make sense, though Id probably still prefer to just put the radiator straight in the pond or swimming pool or whatever.

Also dont underestimate how difficult it is to make a pressurized vessel of any kind. Ive had a smallish commercial pressure filter once, with a 19mm in and outlet.
when I accidentally hooked up the wrong (too powerful) pump, it exploded. Water pressure is nasty.

I was under the impression you had the pump and water flow already (pond filter) needing only a 3/4 inch (garden hose) bypass setup 20-30 psi. As for the rest I guess I was looking at my shed, the drum and scrap is sitting there....although I would have made a purpose built heat exchanger out of the same junk pile.

Have you considered having a fridge evaporator submerged into the oil? More power used but better cooling/control. I have the vac and reclaim gear so maybe not an option if you don't have access.

in your diagram you have not shown how you planned to pump the oil to the oil cooler. Also missing is the number of gpu you need to drown i.e. min dimensions of oil container need to house the gpu.

As i see it your issue currently is the amount of oil required? What if you submerged the oil cooler in the oil and pumped the water though it. This would mean that the water side is an open loop and would need cleaning every so often....

 
62  Other / Beginners & Help / Re: Submersing a rig on: January 25, 2012, 10:35:59 AM
I think you might be surprised how much heat a metal surface area can transfer with liquids on both sides.

Its no different than with a submerged radiator. Assuming your ammo box has equal thermal transfer characteristics as an oil cooler, which I doubt considering the thickness, coating etc, all that matter is surface area and temperature difference between the liquids.  A radiator has a huge surface area for its volume, while with your approach, surface area is directly linked to the amount of oil and scales rather poorly with it (cubic root) .

Mind you, Im not saying it wouldnt be enough but I fail to see the advantage, particularly since I wouldnt be able to flow nearly as much water through the "containing container", so Id have higher water temps.  The rigs will be above pond water level, so I cant use gravity feed, I need pump fed. Since you cant pressurize the container, you need gravity return. Unless I plumb at the very least 50mm water return pipes to the shed, thats going to be a serious limitation on flow rate or cause headaches with the water level. To give you an idea, I use 130mm return pipes in my filter, and with my pump capacity even that creates a 10+cm increase in water levels in the filters. Now I dont think youd need anything like the kind of waterflow I have through the filters, but it sure doesnt hurt, and I already have it, so why not use it? The higher the flow, the lower the water temps.

Quote
I am trying to picture what you are going to do. Are you only putting the cards into the pond if so how will you protect the MB and PSU etc?

Not sure what you mean by protect. Protect from what? Take a motherboard with a few gpu's (probably using extender cables), turn it upside down. Drop the cards in an oil bath. Even if oil would splash on the MB or PSUs or, or the oil creeps up, it doesnt matter. Ill probably prevent this by creating a lid over the oil box though, mostly to prevent dirt from getting in.  I will wire the cables through the lid and seal it (and may use PCIe power extender cables that are fixed in the lid, so the psu cables plug in to the lid), but thats not even necessary.

Sorry I had this picture of a PC hanging from a tree (little birds nesting on it) GPUs hanging down from it into the pond......


Ok so how about this. Take a 44 gallon drum and flow the water in/out, pressurize it. Weld a metal well into the drum to seat the GPUs in an oil bath. The welding would be a little more fiddly and you would want to give it a good hydrostatic test but there is no reason you couldn't do it length ways with the drum on its side. You could also weld fins onto the bottom of the well to maximize surface area.

63  Other / Beginners & Help / Re: Submersing a rig on: January 25, 2012, 09:42:01 AM
I think you might be surprised how much heat a metal surface area can transfer with liquids on both sides. It would be easy enough to test if you have a submersible heater or jug element.

I am trying to picture what you are going to do. Are you only putting the cards into the pond if so how will you protect the MB and PSU etc?
64  Other / Beginners & Help / Re: Submersing a rig on: January 25, 2012, 09:04:46 AM
What about if you used a metal box like an ammo box that you can just fit the cards into. Leave the fans on the cards to circulate the oil. Because the cards fit snugly into the box not as much oil is needed to submerge them, this way you can use the mineral oil rather than run the risk of vegetable oil.

Place the metal box into a larger plastic container of water. Place it the top of the metal box is sitting above the top of the plastic container so any accidental water overflow goes onto the floor not into the box. Pump water into the plastic container and use gravity to take it back to the pond via an overflow. The oil/metal/water interface should be a good heat conductor.

Make sure you put a zinc in the water to stop galvanic series eating the box away.

I cannot see the issue about thermal grease being eaten away, if it was wouldn't just be replaced by the oil that ate it??
65  Other / Beginners & Help / Re: How to vote for/against p2sh? on: January 25, 2012, 06:25:51 AM
So one way to vote no is to join the Eclipse pool?

Unfortunately for me I am not brave enough to cope with their color scheme Cheesy
"No" votes are completely useless. They are exactly the same as not voting at all. Again, this is not a vote.

Sorry I must have missed something? The acceptance of p2sh comes down to 51% of the hash power running the new software? So if you are not solo mining then one way to have a 'vote', so to speak, would be to lend your hash power to a pool that represents your position i.e. running to new software or not.

I have read several of these threads so maybe I have things mixed up
66  Other / Beginners & Help / Re: How to vote for/against p2sh? on: January 25, 2012, 06:03:31 AM
So one way to vote no is to join the Eclipse pool?

Unfortunately for me I am not brave enough to cope with their color scheme Cheesy
67  Bitcoin / Pools / Re: [90 GH/s PPLNS] BitMinter.com *** Merged Mining! *** on: January 25, 2012, 03:14:15 AM
not me I haven't made my first coin here yet.....Cheesy

I started on this pool by mining that very long coin the other day and accidentally broke the server....shhh don't tell anyone.
68  Bitcoin / Pools / Re: [90 GH/s PPLNS] BitMinter.com *** Merged Mining! *** on: January 24, 2012, 12:26:54 PM
it's the coin, it just does not want to be mined Tongue
69  Bitcoin / Hardware / Re: FPGA development board "Icarus" - pre-order acceptable. on: January 22, 2012, 04:14:23 AM
I got my board on Thursday and was thoroughly impressed. The packaging was protective and neatly packed. Everything needed to get up and running was included. After plugging in the board I cloned the Icarus software, read the README for the mining software, modified the .sh file (I am on Ubuntu) and it started working. The board itself is very tidy. It has several LEDs and a power switch. I haven't explored its potential as a development board yet, but I'm sure it would be equally useful there. Thanks ngzhang for the great work!

One slight issue is the mining software seems to always run at 50% of one of my CPU cores (Intel Core i7). Not sure if it's the python version I'm running or the software, but I'm wondering if this would run well on a low-powered PC or even a Rasberry Pi. Anyone try this yet?

Have to agree about the packaging etc. Received in 5 days from shipment date. I think what really impressed me was that the plugpack came with the correct 240v pins for Australia.


Running 3 boards off a micro atx atom 525, no fan on cpu just heat-sink, 80w PSU (overkill), and using almost 0 CPU.
70  Economy / Services / Re: *** Get over 3,500 new Twitter Followers for Almost Nothing -- Only 2 BTC! *** on: January 22, 2012, 03:58:33 AM
Just revived an account, quick service

6,091 followers

never used twitter before so now I will have to go and tweet something, lol
71  Bitcoin / Wallet software / android wallet to webcam client? on: January 20, 2012, 05:12:24 PM

I am still fairly new to BTC so please forgive me if this has been suggested before. My concern is having my BTC secure and easy to use without the headache of use a bootable usb or worry about malware trojans etc.


1. Cheap $50 android pad, no web access ,app that has your private keys and can do transactions (suitably backed up).
2. PC with webcam and a client that keeps track of your transactions plus internet.

Step 1. Display your beneficiaries QR code on the PC's monitor.
Step 2. Use android pad to scan QR code.
Step 3. Carry out transaction and display resulting QR code on pad's screen.
Step 4. Scan Android pad's screen using PC's webcam
Step 5. Client on PC sends transaction to the net.
 
The only communication to the web by the device holding the private keys is via QR code so should be petty much hacker proof.
The inconvenience factor is relativity small in light of other methods such as booting the PC off a USB OS.

What do you think? And better still where can I get the software needed ready made Cheesy

72  Other / Beginners & Help / Re: unhackable wallet concept on: January 02, 2012, 01:46:07 AM

Having a trojan intercept the USB communication is something you can EXPECT will happen if the Bitcoin community standardizes on a monoculture of a specific hardware device.


What if the communication involved copying of a csv file. The only area the PC would have access to is the memory attached to the plug and that could be just enough to hold the incoming and outgoing csv files. So the pic parses the specifiably named csv.

A trojan could not access the PIC program so the only options would be to subvert the copy command, client or overwrite/edit the csv. I cannot see how they could mess with a low level dos command without it being obvious something is up. That would leave overwriting the csv but if they did that the client would pick it up when it verifies. So now the only option i can think of is to subvert/replace the client...... I guess you could double check the csv with notepad but that could not be automated.

unless anyone can think of another way i guess back to the drawing board.

ok, how about if the installer program required a password and then compiled the executable and an encrypted data file based on that password. As the executable was custom spawned it needs specific data that was randomly selected by the compiler onto the encrypted file that also hosts the address book and key list. i guess the executable could be replaced but it could not know the password so would accept any password........but cannot load the address book and key list.

ok i give up for now Smiley

                                          | random num gen |
                                                     |
| usb plug |----| mem for csv files|--| PIC |-----| memory |-----| micro usb socket |
                                                     |
                                               | button |
73  Economy / Trading Discussion / Re: Accusations against shakaru on: January 01, 2012, 10:54:09 AM


First i would like say say that I found this thread hilarious, value entertainment. Thanks go to all contributors and credos to Turbour who posted the cats  Wink

Having just read through the whole thread the money is currently with Astanas CC provider as he put a stop payment on and that is why paypal is holding the transaction because of this stop payment, did I get that right?

Anyhow keep out the good work I am looking forward to further episodes Cheesy
74  Other / Beginners & Help / Re: Does Bitcoin Cater to the Rich? on: January 01, 2012, 06:15:20 AM
Retard.  Smiley

I asked "what?" because your argument makes absolutely no sense.

We're not talking about fiat.  Just because you can argue that fiat caters to the rich does not mean that you can make any conclusions about Bitcoin.  Both can cater to the rich, but if you believe Bitcoin does not, then I would like to hear an argument that makes sense.

At the current rate of around $4 and maximum of 21m coins = theoretical but not practical maximum atm is $84m.

You can not buy a half way decent decent super yacht for that......... so atm bitcoin is not for the rich
75  Other / Beginners & Help / Re: unhackable wallet concept on: January 01, 2012, 05:53:12 AM
Has been proposed, biggest drawback is you're still depending on the computer to tell you what your device is about to sign.  It could say you're sending 5 BTC to merchant A, but really you're sending 5000 BTC to badguy X.  So the device needs a screen.

And with a screen, comes a cost that many are unwilling to pay.  People are already unwilling to pay $29 to secure their thousands of dollars at MtGox.  There would also need to be a secure way to back up the device so your bitcoins aren't gone if it fails - another step that would turn people off.

But otherwise, yes, it would work.

Off-the-shelf refurbished credit card machines are an example of something that would meet the need hardware-wise and are often available at a very nominal cost.  (there's a whole thriving industry of refurbishing CC machines abandoned by businesses that upgrade their systems or go out of business... in this case, refurbishing generally meaning putting old good electronics into brand new made-in-china knockoff enclosures so they look like brand new machines at an affordable price.  Check out eBay for "Omni 3200" for a good example)

What is the hardware requirements for actually generating the key? I am assuming that a 16bit PIC could handle it making the production unit cost under $10.

As for amount verification you have the PIC hold the incoming amount and key and continually stream that back to the client meaning it cannot be overwritten while it is held by the PIC. Have the pic clear that data buy pressing the button or Press button for 3 seconds to generate new key.

I guess there could be a trojan that could emulate the usb stick and intercept communications between the client and PIC using a pin number on the client would not add to the cost............

As for those not spending $29 securing thousands it does make those of us taking minimal precautions safer via the low hanging fruit method Smiley
76  Other / Beginners & Help / unhackable wallet concept on: January 01, 2012, 04:41:04 AM
I have been reading up and there appears to be a lot of concern about wallet security against thieves and trojans. There seems to be a lot of methods for making your wallet more secure and most are a PIA.

I have an idea using hardware but do not know how feasible it would be....I am hoping those with more experience might comment on it.


| usb plug |------| PIC |-----| memory |-----| micro usb socket |
                           |
                     | button |


The idea is to have a usb stick with a micro processor built in such as a PIC. The key data is stored in memory only directly accessible via the mico usb slot.

Steps
1. Store all primary keys on memory via micro usb socket (one time only with precautions)
2. plug into PC via usb plug
3. the client sends key data to PIC (recipient key, amount and number of primary key needed)
4. PIC relays same data back to client for verification
5. User presses button for PIC to generate new key off the selected primary key and send result back to client.
6. Client now has payment data and at no time did it have access to any primary key.

As the PC has no access to the primary keys and physical access is needed to generate a pair I don't see how a hacker could steal money.....unless i am missing something.


What do you think?
 
77  Other / Beginners & Help / Re: Introduce yourself :) on: January 01, 2012, 03:58:20 AM
hi all. want to get into mining using fpga and look forward to discussing it
78  Other / Beginners & Help / Re: Newbies Hangout on: January 01, 2012, 03:50:04 AM
hey so i am a total nube but i thought this thing was like an untracebal ebay of sorts and i am confused as to how this system works? i have been reading through posts but this computer jargin is leaving me confused...help please!


I am a newbie to bitcoin too. I'll give a simple explanation a try...

A bitcoin is a digital object that it cannot be copied to increase its value.

Think of it like a cheque. If you made many perfect copies this would not increase the value because the bank has records and will bounce all but the first one submitted.

The bank has central records to keep track of transactions. Bitcoin uses an encrypted file on a p2p network to record transactions and uses peers to verify and process these transactions. The bank uses armored truck, security guards and FBI ect. to keep their money secure. Bitcion relies solely on ultra secure encryption methods.

To receive a bitcion you send your encryption signature generated from your primary encryption key to the person sending the money. That person adds the amount along with their signature and your signature and sends it to the p2p network to be verified and processed. Once this is done that amount of money is added against your primary signature on the master record bouncing around the p2p network thus enabling you to generate money off your primary key that can be validated.

As to anonymous ebay you could in theory go to a website on via TOR and pay for something using bitcoin.
79  Other / Beginners & Help / Re: Could bitcoins be made illegal? on: December 31, 2011, 10:59:42 AM
i think it is safe for now unless it is used for pirating movies  Grin
80  Other / Beginners & Help / Re: Newbies for FPGAs on: December 31, 2011, 07:09:48 AM
+1 for me. I created this account just to research an FPGA miner I could also use for electronic hobby projects.

A.J.

same here Smiley
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