tjgq

9 ms·

31.
by tjgq 12y ago
Not really "at length", but he goes a bit into why he thinks computation should be decentralized here: http://rob.pike.usesthis.com/
32.
by tjgq 12y ago
Not everyone thinks the same way. There are certainly lay persons out there who do not find proofs by contradiction jarring when they come across them for the first time. I remember I was one of them. But the impression I get from my (possi
33.
by tjgq 12y ago
> I have to disagree. A trained mathematician understands why a proof is or it not valid, based on a combination of axioms and a logical sequence predicated on axioms, but with no gaps or overlooked assumptions. First off, to dispel any
34.
by tjgq 12y ago
To expand a bit further: this is an example of the "rabbit-hole" nature of mathematics. All but the most trivial theorems depend on previous results, and in most cases you cannot realistically follow all the dependencies until you
35.
by tjgq 12y ago
Thanks for the background! I didn't know about the original dnscat - that's why I mentioned iodine in case someone was interested in trying this out as a tunneling method. And thanks also for your thoroughly enjoyable talk.
36.
by tjgq 12y ago
> 2. If it's not prime, it has divisors. This proof claims it must include divisors that are prime but are not among those we started with. <-- THIS IS THE BIT I DON'T GET This step of the proof invokes the Fundamental Theor
37.
by tjgq 12y ago
The overall structure of the proof is not by contradiction, but one of the steps is. The Wikipedia article calls this out, right after the sentence you quoted.
38.
by tjgq 12y ago
Slide 56 onwards (2-way communication over DNS) is basically what Iodine [0] does to defeat firewalls. Quite a cool hack. [0] http://code.kryo.se/iodine/
39.
by tjgq 12y ago
In my humble opinion, proofs by contradiction are not the best examples of mathematical reasoning to be presented to the uninitiated. It has been my experience that people untrained in mathematics find it difficult to (intuitively) accept t
40.
by tjgq 12y ago
What happens when you write var x []string = strs ? If you make a copy of the slice's underlying array and point x to the copy, then you are hiding a potentially expensive allocation behind an apparently innocuous initialization
41.
by tjgq 12y ago
> I was trying to say something like this; I don't think it's true that you don't ever store full addresses in a router (You don't always store the address, sometimes just a prefix), but when you are describing a dest
42.
by tjgq 12y ago
Apart from the fact that "geographically close" does not always coincide with "network-wise close", that's essentially the principle behind route aggregation as used by routers today. However, applying it successful
43.
by tjgq 12y ago
IPv6 addresses are larger, but routers only store prefixes, not full addresses. And yes, one of the design goals of IPv6 is to reduce address fragmentation, allowing the global routing table to contain fewer and shorter prefixes. That'
44.
by tjgq 12y ago
> "universal constants" are really just statistically measured values. Except for the speed of light, interestingly.
45.
by tjgq 12y ago
I'm curious: can you name an optimization problem you would get that intuition from?
46.
by tjgq 12y ago
First off, good luck trying to implement any kind of decentralized network service when almost nobody has a globally routable address. Second, if ISPs are willing to keep records of IP-address-to-customer mappings, it's not much of a s
47.
by tjgq 12y ago
Also read Russ Cox's writeup on implementing regular expressions [0]. Backtracking can be done efficiently; it's just that most regular expression engines have suboptimal implementations for it. [0] http://swtch.com&#x2
48.
by tjgq 12y ago
Google has a system [0] whereby their crawler appends a special parameter to the query string to signal that you should serve a static, "indexable" version. What I get from this announcement is that their crawler is becoming good
49.
by tjgq 12y ago
> There is no such service. Not only does it not exist, it cannot exist. No ISP can provide that. Any independent network on the Internet can start dropping your packets tomorrow for any reason. Including a lazy admin filtering out your
50.
by tjgq 12y ago
> The kind of software that everyone uses, but that is not a differentiator ("the secret sauce") that makes something stand out. Doesn't OpenSSL fit this definition perfectly?
51.
by tjgq 12y ago
> The author advocates for treating telecom infrastructure like public utilities, but then says that competition is the answer. These are not compatible ideas! They are compatible if you decouple the infrastructure owner from the service
52.
by tjgq 13y ago
In most systems, this will only work within the same process. Contemporary Unix kernels always allocate zeroed pages to processes, so it's impossible for a process to recover data from another unless there's a kernel bug.
53.
by tjgq 13y ago
I suppose (s)he means that, if you squash commits, you lose the intermediate states containing code that was later deleted. It's not necessarily bad - squashing is a useful tool to clean up your changes before you merge them in.
54.
by tjgq 13y ago
Also reminiscent of this quote from Dijkstra [0]: My point today is that, if we wish to count lines of code, we should not regard them as "lines produced" but as "lines spent": the current conventional wisdom is
55.
by tjgq 13y ago
Ah, the memories. I had to thrice reinstall DOS on my childhood computer because of that. I later learned that editing binary files in a text editor wasn't a very bright idea...
56.
by tjgq 13y ago
You should read the article to answer your own question in depth. The short version is: on Linux, both /dev/random and /dev/urandom are fed from the same CSPRNG. A CSPRNG only needs to be seeded with a few bits of entr
57.
by tjgq 13y ago
I think the widespread practice of Android applications storing potentially large data in /sdcard dates to a time when /data was extremely small on most phones, and would fill up quite rapidly if you had a large number of applic
58.
by tjgq 13y ago
By that same logic, all websites are European (Swiss? French? German?) because HTTP was invented by Tim Berners-Lee while at CERN.
59.
by tjgq 13y ago
It's worth noting that during the transition period the core routers will actually need more memory and processing power, since they'll have to route both IPv6 and IPv4 prefixes for most destinations.
60.
by tjgq 13y ago
I think (and the article also suggests) that it is especially hard to explain to people who come from a CS background. We often get too caught up in our own way of seeing the world that does not, for better or worse, correspond to how mos

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