keithwinstein

6 ms·

1.
by keithwinstein 2mo ago
This is really cool stuff, and I agree the future is likely to look more like this. I was surprised by the last two paragraphs ("Aside: verified assembly") -- my understanding was that this future is basically already here. I beli
2.
by keithwinstein 3mo ago
Looks very interesting! We have done a lot with WasmCert-Isabelle (and there's also WasmRef-Isabelle and their 2023 paper, and the earlier WasmCert-Coq); other than being in Lean instead of Isabelle/HOL or Coq, how would you compa
3.
by keithwinstein 3mo ago
> Constitutionally, only the federal government is allowed to regulate intellectual property It turns out that's not exactly the case! See, e.g., Goldstein v. California, 412 U.S. 546 (1973). Before 1978, state (often common law) c
4.
by keithwinstein 4mo ago
> For 8-bit, 16 maps to 7.5IRE which is the well understood legal black. Mapping 235 means they mapped peak to 110IRE. Generally no -- in an 8-bit NTSC-M Rec. 601 system, 16 maps to E'Y = 0 at 7.5 IRE, and 235 maps to E'Y = 1 a
5.
by keithwinstein 5mo ago
I can't speak to Binaryen, but afaik WABT's wat2wasm and wasm-tools's wat2wasm (aka wasm-tools parse) are both 100% spec-correct in this respect. Parsing the Wasm text format doesn't require any knowledge of the type of
6.
by keithwinstein 8mo ago
I'm sorry you're going through this! But also a little suspicious because a nearly word-for-word message was posted four days ago on Reddit with some of the details different, including the major and presence of a master's de
7.
by keithwinstein 11mo ago
> Even more pedantically, “standard time” is not necessarily consistent across each zone (particularly, during the period for which in parts of the zone it is advanced by an hour) since "standard time” only advances for those states
8.
by keithwinstein 11mo ago
If we're being really pedantic, in the U.S. context the zones observe "standard time" all year. "Standard time" refers to the standardization across the zone, and the practice of advancing the clock during daylight-
9.
by keithwinstein 1y ago
Shades of https://www.theregister.com/2006/03/24/tuttle_centos/ (from simpler times, almost 20 years ago!)
10.
by keithwinstein 1y ago
This story has been reposted many times, and I think GJS's remarks (as recorded by Andy Wingo) are super-interesting as always, but this is really not a great account of "why MIT switched from Scheme to Python." Source: I wor
11.
by keithwinstein 1y ago
You don't need ATSC 3.0 to do this kind of thing! The short-term stability of the oscillators they use for commercial DTV transmission is apparently good enough that just having one local reference to compare GPS vs. each TV station&#x
12.
by keithwinstein 2y ago
I think you're both right in a sense. Bazel doesn't (in general) prevent filesystem access, e.g. to library headers in /usr/include. If those headers change (maybe because a Debian package got upgraded or whatever), Baze
13.
by keithwinstein 2y ago
The first edition of SICP came out in the fall of 1984 (a year after these Hofstadter columns). This fall is the 40th anniversary!
14.
by keithwinstein 2y ago
No -- as discussed upthread, clang's musttail attribute requires the target function to have the same number of arguments as the caller and for each argument to be similar to the corresponding caller argument. That's stricter than
15.
by keithwinstein 2y ago
Yes, wasm2c implements the Wasm tail-call feature with trampolines, exactly this way. ( https://github.com/WebAssembly/wabt/blob/main/test/wasm2c/ta... has an example.) Doing it with a trampolin
16.
by keithwinstein 3y ago
I don't think that's quite right -- I think you're thinking of 1601 S. California Ave. Faceboook had there and 1050 Page Mill, but not 1501 Page Mill afaik -- that was HP/HPE until recently and is still an office buildin
17.
by keithwinstein 3y ago
My understanding is that jitter refers to essentially stochastic variation of an ideally isochronous/periodic process or signal. You might say "the event is supposed to occur exactly every 1 second; in practice we observed jitter
18.
by keithwinstein 3y ago
You're definitely right that Boston Light is officially in Hull, but The Graves (still a USCG-managed lighthouse, and bigger than Boston Light) is in Boston. See https://arc-gis-hub-home-arcgishub.hub.arcgis.com/dataset
19.
by keithwinstein 3y ago
I met Sally Snowman a few times -- we used to visit Boston Light 1-2 times every summer on MIT's sailboat with a group of students. She was super-welcoming and shared a ton of knowledge and stories about the lighthouse and station. We
20.
by keithwinstein 3y ago
The goal usually isn't for one party to take a C program and transform it into "safe" machine code. The goal is for a possible adversary to take a C program and produce an IR, and then for somebody else (maybe you) to valid
21.
by keithwinstein 3y ago
Well, a bunch of ways. It's much faster to execute than adding a software bounds-check on every load. (Because the module declares its memories explicitly, it's very easy for a runtime to use a zero-cost strategy to enforce that m
22.
by keithwinstein 3y ago
It takes tens or hundreds of microseconds to launch a new thread on Linux, and tens or hundreds of milliseconds (or more) to launch a new VM. It takes tens of cycles to instantiate a Wasm module and call one of its exported functions. The
23.
by keithwinstein 3y ago
wasm2c (part of WABT) does this transpilation in a spec-conforming way; it passes all* the WebAssembly tests and enforces the memory-safety and determinism requirements and the rest of the spec. The memory bounds-checking itself doesn'
24.
by keithwinstein 3y ago
ObNote that in standard English it's "premises," even for a single building. Some explanation here: https://ahdictionary.com/word/search.html?q=premises
25.
by keithwinstein 3y ago
:-) The UTF-8/Unix FAQ and existing terminal emulators don't agree with you here. As you say, there's no spec for this, but here's what Kuhn's FAQ says ( https://www.cl.cam.ac.uk/~mgk25/unicode.h
26.
by keithwinstein 3y ago
FWIW, I wouldn't try to parse escape sequences directly from the input bytestream -- it's easy to end up with annoying edge cases. :-/ In my experience you'll thank yourself if you can separate the logic into something l
27.
by keithwinstein 3y ago
No -- in 2019 Google Ad Manager announced it was moving to a first-price auction ( https://blog.google/products/admanager/simplifying-programma... ) and AdSense followed in 2021 ( https://support.google.co
28.
by keithwinstein 3y ago
For clarity, you don't really need a "browser-grade sandbox" for this -- the wasm2c route that Firefox/RLBox are using is quite lightweight. The only runtime support necessary is basically malloc/free + a signal han
29.
by keithwinstein 3y ago
Not so -- 1080p24 and 1080p30 sequences (and the 1000/1001-rate versions) were part of the original A/53 specification in 1995. This is for H.262 video (MPEG-2 part 2). It's also in the 2007 revision (see A/53:2007 part
30.
by keithwinstein 3y ago
Just to be pedantic, 1080p24 (and 1080p30, and the 1000/1001-rate versions) are already allowed by the existing A/53 spec and have been since 1995. The big (1080-line) broadcasters usually transmit their film-style programming as

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