Then the only remaining issue is the physical security: that the miners using experimental chips did not go missing in the night or the owner of premises for the mining farm repossesses/places a lien on the equipment for nonpayment of the rent or electricity bills.
If it's a "legit" co-lo facility, security can be part of the package. How secure depends on the facility and how much you want to pay...
Edit: I remember seeing the photographs of the DRAM banks for the aforementioned hardware RAM disks. The DRAM chips were all in DIP packages and all socketed. To avoid the theft the DRAM banks were then cemented to steel plates on top to prevent individual removal. One of the "thefts" to prevent was actually not theft (chips goes missing) but unauthorized replacement (experimental chip replaced with an off-the-shelf equivalent). Apparently in the DRAM business seeing and measuring un-binned chips would allow detailed reverse-engineering of the manufacturing process. This includes not only taking the actual possession of the experimental chip and de-capping it but also a temporary removal from the original socket to run a battery of post-manufacturing electrical tests and then putting the chip back in the original circuit.
When I was working for a prominent US DSP chip maker on one of their engineering test floors, there was a Schlumberger scanning electron microscope (I believe) that was used to test silicon. What it displayed on the screen was pretty interesting and what it could do was pretty sweet. You could see all sorts of details, and based on the colors tell what elements were used and whether a particular trace was energized or not, and if I recall you could tell the difference between voltage levels. Virtual probes allowed you to measure signals and display them in a "scope" window. Granted this was in 1989-1990 time-frame so I know there is way more capable and cooler sch!@t available now.
- zed
EDIT: fixed spelling of Schlumberger...