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tzot

274 karma · joined June 14, 2020

Just an earthbound misfit, I.
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tzot··on The tiny chip that powers Montreal subway tickets
Yep, the ones in Athens can be refilled too.
tzot··on Let's write a video game from scratch like it's 1987
Simon Tatham's Mines Windows exe stands at ~180KiB as seen at https://www.chiark.greenend.org.uk/~sgtatham/puzzles/
tzot··on Show HN: ESP32S3 ZXSpectrum
OK, I give up; I can't find an easter egg, except maybe for the simulated “curve reflection” on the spectrum on the right (but I wouldn't call it an easter egg, so most probably it isn't what you mean).
tzot··on Django SQLite Production Config
Indeed on rereading my question I see it was not phrased correctly.

Yes, the `journal_size_limit` affects the maximum journal/wal file that remains on disk if larger than that — and by the way ensures that these files are not deleted once created.

Your setting it to ~25MiB while the default `wal_autocheckpoint` PRAGMA is set to 1000 pages (with the typical page size of 4KiB that means after ~4MiB the WAL file contents will get moved to the main database file if no other transaction is active) is what confused me. 25MiB seems very specific for a file size to keep in the occasion that the WAL file keeps growing beyond 4MiB. Perhaps you also meant to tinker with the `wal_autocheckpoint` PRAGMA but didn't?

tzot··on Django SQLite Production Config
Is there a point for the PRAGMA journal_size_limit when we set the database to WAL mode?
tzot··on First pictures from Euclid satellite reveal billions of orphan stars
OTOH the phrase “a thousand million” for 10⁹ is not that uncommon. From what I've seen, in places where billions/trillions are mentioned and it's important that the number is accurately specified, a representation with digits or the exponent of 10 are typically provided.
tzot··on First pictures from Euclid satellite reveal billions of orphan stars
“Scientifically standard” are the SI prefixes. So, given the ambiguity of what 1 gigastar is (1/1000th of 1 terastar or a really huge star?) one should say “10¹²s of stars” maybe.
tzot··on Sir, there's a cat in your mirror dimension
“Stegatography” can be an even more appropriate choice if you speak one of the languages born around the European side of the Mediterranean sea.
tzot··on Commodore 64 runs AI to generate images
Even if “paleo-” means “old” and “archaeo- / archeo-” means “ancient”?
tzot··on Japan's Moon lander makes it through another lunar night
Perhaps you misread -247°C as -274°C?
tzot··on Keep Out – WebGL Game
So, arrow keys, SPACE un/holsters weapons, End flip 180°, Del/PgDn for strafe left/right. How do you fire the weapons?
tzot··on HTTP/2 Continuation Flood: Technical Details
I just love this typo:

> After serveral retries

tzot··on The return of the frame pointers
I am not sure, but I believe -fomit-frame-pointer in x86-64 allows the compiler to use a _thirteenth_ register, not a _seventeenth_ .
tzot··on Monodraw
I believe here ASCII was used not as in ASCII-the-standard but as “ASCII” in ASCII-art. I also believe that ASCII art should actually be called “monospaced Unicode text” since people doing ASCII art have been using as many codepoints as were available in their platform of choice.
tzot··on Let's talk about joins
This is a nice trick using full outer join! My question to wood_spirit still stands, though.
tzot··on Let's talk about joins
> All the other non-left joins are just syntactic sugar and can be expressed using only left join…?

A “vertical join” (SQL UNION) is one of the “non-left joins”. How can you transform a “vertical join” to a “left join”?

tzot··on 9999999999999999.0 – 9999999999999998.0
TCL does for quite some years now use real integers (unbounded size) and floats (float8) whenever possible. By the way, the article does not specify versions of languages, so:

    $ tclsh
    % puts $tcl_version
    8.6
    % expr "9999999999999999.0-9999999999999998.0"
    2.0
tzot··on Light can make water evaporate without heat
As I understand it, when you heat water, you give energy to all of the water molecules that start moving faster in their random direction. So molecules that were directed towards outside the water mass are “directly” extracted, and the rest will bounce around in the increasing pressure until they are “indirectly” extracted (I used “directly” and “indirectly” non-scientifically here, just to make a distinction.) It takes quite a lot of energy which leads to evaporation over time.

I think what they found is a set of circumstances where the energy of the light “chips off pieces” of water, so the energy needed is much less. A small broken-off “piece” (or cluster of water molecules) has a very large ratio of surface area over volume, so the rest of the evaporation is taken care of by the surrounding environment as-is.

tzot··on Light can make water evaporate without heat
Did you get a green light to make that joke here?
tzot··on The Philosophy of Humor: What Makes Something Funny? (2022)
> I think Heinlein nailed it in Stranger in a Strange Land.

Also in _The Moon Is a Harsh Mistress_ he made the research of what is humour be one of the primary self-assigned directives of Mike (the accidentally created GAI).

tzot··on New world record with an electric racing car: From 0 to 100 in 0.956 seconds
The word “dedicated” does not correspond to verifiable facts, since `units` can do dimensionless / unitless calculations just fine; it is already a calculator with units built-in, and the example you provided only intensifies the impression that `qalc` and `units` are equivalent.

IMO a proper pro-tip for `qalc` would need an explanation why one should prefer it over `units`.

tzot··on NASA’s Webb finds carbon source on surface of Jupiter’s moon Europa
While on the subject of etymology, spelling the Greek word “dilemma” (δι+ληπ+μα) incorrectly does not help with providing a definitive answer as a Greek. I'm not starting a flame war, I just make an observation (and as it happens, I'm a fellow Greek).

Yes, the word “European” (inhabitant of Europe) is rooted on the Greek word Europē, Zeus' mythical mistress (one of many), after whom both the continent and the satellite were named, but is the “-ean” a proper transcription from Greek?

Perhaps “Europaean” could be the better answer to the question we discuss; after all, in English the continent's name is a modernized “Europe” while the satellite stays closer to the intermediate Latin as “Europa”, and since this discussion is in English, I feel that the difference in suffix justifies a different label for the inhabitants of the satellite.

tzot··on New world record with an electric racing car: From 0 to 100 in 0.956 seconds

    $ units
    You have: 100 km per hour / 0.956 sec
    You want: gravity
        * 2.9629132
        / 0.33750567
tzot··on You Don't Need UUID
> I'm really reaching here, but an ID that omits special characters is easier to extract from a url, since it can be double-clicked in a URL bar to select it, whereas a GUID with hyphens forces the user to select the beginning and the end of the string.

The is-hyphen-part-of-a-word issue depends on the text control (browser, UI widget library, …) / terminal you use, which is not universal.

In any case, the hyphens/dashes are not required part of the representation, and one can use the “dashless” representation (exactly 32 hex digits) in URLs and in-code without any issues whatsoever, as far as I know; for example, Postgres accepts either “dashful” or “dashless” UUIDs the same.

tzot··on My favorite prime number generator
The fastest variant I know of this algorithm is the one found at https://stackoverflow.com/a/3796442/6899 :

    import itertools as it
    def erat3( ):
        D = { 9: 3, 25: 5 }
        yield 2
        yield 3
        yield 5
        MASK= 1, 0, 1, 1, 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0,
        MODULOS= frozenset( (1, 7, 11, 13, 17, 19, 23, 29) )

        for q in it.compress(
                it.islice(it.count(7), 0, None, 2),
                it.cycle(MASK)):
            p = D.pop(q, None)
            if p is None:
                D[q*q] = q
                yield q
            else:
                x = q + 2*p
                while x in D or (x%30) not in MODULOS:
                    x += 2*p
                D[x] = p
tzot··on The Real Question Behind 'What Do You Want?'
Yes, ranked wants with artificially restricted phrasing have exactly this problem you describe.
tzot··on The Real Question Behind 'What Do You Want?'
In the context of an absolute ranking system, the choice is to act towards the higher-ranked want vs the lower-ranked want, so the resolution is simple: the higher-ranked wins. If one values completion over incompleteness, then one can prioritize that want over all (or many) others.
tzot··on The Real Question Behind 'What Do You Want?'
If one can absolutely prioritize their “wants” (no “want” has equal rank with any other), then any choice between two of them is simple: choose the higher ranked and “sacrifice” the lower one, right?
tzot··on North American English Dialects
Is the etymology really needed in this case to know how to pronounce "c"?

I believe in -ce- -ci- -cy- the c is an s, while in -ca- -co- -cu- the c is a k.

Perhaps the etymology is needed to know how to write a k/s sound you've never heard before.

tzot··on My favorite Vim oneliners for text manipulation
> I should've recognized \s as the space character. … whitespace pattern.
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