sdab
Joined 12 years ago
Joined 12 years ago
As for how to prepare the images, you need a ramfs image with the root filesystem as a cpio file and a kernel as a vmlinuz file. You then serve these in a basic HTTP file server that your iPXE config points to.
Generating the vmlinuz file is pretty easy given a kernel. The cpio file is trickier. netboot.xyz recommends just grabbing a standard distribution. Otherwise this reduces to the problem of creating your own.
Yet another quote for the misrepresentation of science in articles.
Having just re-read Lynch's paper, can you explain what you mean here? I didn't see anything explicitly relying on time. It could be there is some implicit usage I didnt see. Additionally, the paper's impossibility result is about "perfectly correct consensus" which applies with and without clocks and then has a positive result for "partially correct consensus" (i.e. not deciding a value is a correct result). Im not sure which you mean when you say "consensus becomes impossible" as it is either already impossible (the perfectly correct protocol) with one faulty process or (to my understanding) not dependent on time (the partially correct protocol).
p.s. great article!
These computers are quantum adiabatic computers which are indeed quantum in that they use qbits, but it is not clear that they can perform some operations required for QBP problems. See scott aaronson's blog for more info [1].
These are often confused in articles, do you happen to know if that was the case in this article? Did they mean 1180 MWH or 1180 MW as stated? Otherwise your yearly production calculation is very off. 1180 MW (j/s) would produce 10^7 MHW per hour.
Two links deep, I found [1]. The salient being "...floating point representation gives you extra precision for numbers near zero, this extra precision comes at the expense of precision for numbers further out"
1. http://www.pathengine.com/Contents/Overview/FundamentalConce...
Did the experiment limit a user's participation to one time? Otherwise, the results might be skewed and the benefits exaggerated.
https://www.reddit.com/r/cpp/comments/3gd29t/c_internals_stl...
Thanks for the puzzle, its hard to find good concurrency problems.
Edit: Looked through your solution. You are right, we thought of similar things. I started out by wanting a multi condition variable, but didnt want to implement it :). I ended up getting something similar in a roundabout way.
I believe it follows all of the requirements. There is one glaring flaw which is that it uses a condition variable per 'wait_until_equal' call, though it uses only N mutexes. So this doesn't fall under the N^2 primitives (in the case of many waits), though its unclear to me if thats an official rule.
Im happy to listen to feedback or if someone sees an error.