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Topic: Request for Discussion: proposal for standard modular rack miner - page 11. (Read 9671 times)

legendary
Activity: 2128
Merit: 1073
Isn't 10in roughly the same size slab as a GPU these days?
Have you ever looked under the GPU's heathsink? How many chips it touches and where are the chips in relation to the heathsink?
newbie
Activity: 12
Merit: 0
Ah makes perfect sense, thanks for the explanation!

Additionally, you could test individual boards outside the box with a cheap USB cable and anything running cgminer.

It would be pretty cool to sell all in one miners (case, power, hasing boards and cooling) AND having a USB interface and 6pin power would allow users or GS to build out smaller miners using (roughly) the same equipment but in a PC mid tower with 3-4 hasing boards, or even a single board sitting on your bench using a 140mm fan just sitting on the heatsink and whatever PSU's you have laying around.

Point being standardizing the hardware (hasing boards controllers) and connectors provides (limitless) options for mounting and scalability -- I love it!

10 inches long contiguous aluminum heathsink?

The thermal expansion of such a slab of aluminum will be literally ripping the chips off of the PCB.

Either the heathsink or the PCB needs to be partitioned into sectors.


Isn't 10in roughly the same size slab as a GPU these days?
legendary
Activity: 2128
Merit: 1073
10 inches long contiguous aluminum heathsink?

The thermal expansion of such a slab of aluminum will be literally ripping the chips off of the PCB.

Either the heathsink or the PCB needs to be partitioned into sectors.
legendary
Activity: 3374
Merit: 1859
Curmudgeonly hardware guy
The Block Erupter Blade backplane was power only. There was no signal interconnect, no centralized controller.

If we wanted a backplane it'd either be at the bottom (which can cause board security problems like the famous S2 shipping disasters) or at one end (which blocks your airflow), neither of which are terribly optimal. Small out-of-the-way cables cause no airflow restrictions to the main heatsinks, and without a baseboard you can secure your boards quite solidly with a few screws and not need additional runner slots in framework. Having a backplane board adds to the cost both in electronics (an additional large PCB and the cost of edge connectors on every hashboard) and in framework (as now you have to make steel runners as well). Additionally, you could test individual boards outside the box with a cheap USB cable and anything running cgminer.

I feel USB cabling is the best overall solution when cost, ease of manufacture and overall reliability are prioritized.
newbie
Activity: 42
Merit: 0
okay sounds good so far. i would like more inter changeability of hashing boards no point re-buying the wheel each time.
newbie
Activity: 12
Merit: 0
Can you talk a little about why USB was chosen over saaayyy a PCI-E bus (a la Block Erupter Blade backplanes)? My thought would be that a USB driver is easier to work with but PCI-E is pretty cool and very modular...
legendary
Activity: 3374
Merit: 1859
Curmudgeonly hardware guy
I will not use USB3.0 for the data bus because there are no good options for USB3.0 to microcontrollers or primitive protocols which hashing chips are likely to use. USB2.0 should have more than enough bandwidth for everything.

There would be no box with 12 boards on the controller. At most 8. One controller per box, ethernet out. The USB interconnect is strictly internal, tying the controller to the hashing boards.
newbie
Activity: 42
Merit: 0
i would plan on using usb 3.0 for the data bus as it can move the data with less delay and you plan on making it have 8 hashing boards correct? with the amount of data on the bus require one controller per box? as in a box with lets say 12 boards on controller there links to the usb port on the main box with one, is this doable?
legendary
Activity: 3374
Merit: 1859
Curmudgeonly hardware guy
So this first post will be somewhat incomplete. I have as of yet no diagrams drawn up except sketches on paper. Dimensions are currently in inches, but a fairly universal standard should probably be defined in metric since the majority of manufacturers and customers would be more familiar with that system.

But here's the score so far. I am interested in building miners that don't suck. To that point, I am interested in building miners with reusable parts, with standard interfaces and with full adjustability of chip-level operating points inherent to the design.

My intention to build a board which can fit on an AntMiner S1 chassis has already been discussed at length. I have no problem using that base hardware as a fairly standard small-format miner. I don't know of any terribly good large-format (say, rack-mountable) miners which are generic enough to do what I'd like. So Novak and I have discussed and would like to propose for comments a basic standard for rack-mountable bitcoin miner, which is designed to be inherently flexible and upgradeable.

I should have some layout diagrams generated in the next few days, but for now I'll give a bit of a text description.

The case

4U Rack-mountable, 7 inches high by 17.5 inches wide outside dimensions.
A total of six 38mm 4-wire PWM fans, three 140mm at the front and three 120mm at the back in push-pull configuration.
Two server-grade power supplies, 1U height, probably DPS-1200 or functional equivalent, mounted at the top rear on an internal shelf separating the hashboard volume from the upper chamber containing controls and cabling.

The hashboards

The span between front and rear fans (inside to inside) is 15 inches.
The hashboard PCB is five inches tall by twelve inches in length and bearing two heatsinks.
The main heatsink is four inches tall by ten inches in length with a total fin height of no more than 1.38 inches.
The secondary heatsink is four inches tall by ten inches in length with a total fin height of no more than 0.5 inches.
The secondary heatsink would be drilled for screws to run through, through the PCB and thread into the main heatsink. This is so that the secondary heatsink can, if the PCB design calls for it, be removed without hindering the mounting of the PCB to the main heatsink.
The main heatsink would be drilled and tapped through the fins such that it can be screwed to the bottom panel of the case.

The heatsinks will be aligned with the rear bottom corner of the hashboard, such that the topmost one inch and frontmost two inches of the hashboard have no heatsink contact on either side. This gives room for through-hole components, VRMs, connectors and other circuit parts.

There is a one-inch gap between the front of the hashboard and the inside of the front fan. There is a two-inch gap between the rear of the hashboard and the inside of the rear fan. Hashboards would be mounted perpendicular to the bottom of the case, with heatsink fins extending horizontally outward from the board.

Each board should have two 6-pin PCI connectors extending at a right angle from the top of the board, just past the end of the heatsink (the rearmost edge of the rearmost jack would be 10" from the rear of the board). To the front of the frontmost jack is the USB header. All connections would be accessible from holes punched in the separator shelf.

8 boards will fit widthwise across the inside of the case with a bit of room inbetween to ease vertical installation.

Boards should be limited to 300W maximum power dissipation each.

Controls

It's our intention that the controller can be fairly generic. Any small single-board-computer like the Raspberry Pi, Cubie or BeagleBoneBlack would be suitable provided it had both USB and Ethernet connections accessible, and one could compile cgminer for said device.
A space inside the upper chamber would be reserved for a "drawer" onto which the controller is mounted; dimensions for this are to be determined and a replacement controller should be provided with its own "drawer" tapped in the proper places for mounting said controller.

A board specific to the miner is to be assembled providing a modified USB interconnectivity on 8 ports. The connection would be a six-pin header, onto which would be socketed a cable with five wires and a shield. Four of the wires carry standard USB lines (5VDC, GND, D+, D-); the fifth wire carries a logic-level signal for a status LED. The sixth pin connects to the cable's shielding. An identical six-pin header would be present on the hashboard, which enumerates as a USB device and controls the status LED. The status LEDs would be visible through the front panel of the miner.
This board connects to the controller, which sees it as an 8-port USB hub.

The board would connect to thermocouples mounted in the airstream in front of the rearmost fans. All six fans would connect to this board, which would use the thermocouple feedback (and a calibration trimpot) to determine fan speeds, individually for each pair of fans.
Alternatively, if software control was desired, the controller could link on an unused USB line and interface with a cgminer driver tasked with determining fan speed from hashboard reports and pass commands to the controller on the board.



The goal of this endeavor is to define a standard box inside which any board designed for its form-factor could be run. By using a standardized dimension, heatsink and USB interconnect, boards from different manufacturers with different chips operating on different protocols could all be run in the same box off the same controller. Operating new boards might require updating cgminer on the controller to detect the new hardware. Piecewise upgrades would be readily possible as hashboards could be sold individually. As long as the basic dimensional standards are met, as well as the basic operating standards (12V 300W max, USB connection) and avoiding software conflicts, any number of small or large manufacturers could produce any number of boards which could all be run together in the one box. Replacement parts for the machine itself would be both standardized and fairly generic. The benefits in cost savings, maintainability and diversifying the market are substantial.
I know it's not a perfect household miner being as it would look to draw over 2.4KW power. The point is not to build a perfect household miner.


So, that's the gist of our idea. Anyone got any comments?
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