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The_Decryptor
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135
Joined
9 mo. ago

ISO 8601

  • It's an easy fix at least, just check if you're comparing numbers on both sides and switch to a simple numerical sort.

    I think Windows used to get this wrong, but it was fixed so long ago that I'm not even sure now.

  • So one of the problems is the size of a "physical page", on a stock x86 system that's only 4KiB. If you allocate just 1MiB of RAM you need to back that with 256 "page table entries", and to then load a virtual address within that allocation you need to walk that list of 256 entries to find the physical address in RAM that the CPU needs to request.

    Of course these days an app is more likely to use 1 GiB of RAM, that's a mere 262,144 page table entries to scan through, on each memory load.

    Oh but then we're also not running a single process, there's multiple processes on the system, so there will be several million of these entries, each one indexed by address (Which can be duplicated, each process has its own private view of the address space), and then by process ID to disambiguate which entry belongs to each process.

    That's where the TLB comes in handy, to avoid the million or so indexing operations on each and every memory load.

    But caching alone can't solve everything, you need a smarter way to perform bookkeeping than simply using a flat list for when you don't have a cached result. So the OS breaks down those mappings into smaller chunks and then provides a table that maps address ranges to those chunks. An OS might cap a list of PTEs at 4096 and have another table index that, so to resolve an address the CPU checks which block of PTEs to load from the first table and then only has to scan the list it points to.

    Like this, this is a 2 level scheme that Intel CPUs used before the Pentium Pro (iirc), the top 10 bits of an address selected an entry in the "page directory", the CPU loads that and uses the next 10 bits to select the group of PTEs from that list, following that link that it finds the actual PTEs that describe the mappings and then it can scan that list to find the specific matching entry that describes the physical address to load (And it then promptly caches the result to avoid doing that again)

    So yes, for a given page size and CPU you have a fixed number of walks regardless of where the address lives in memory, but we also have more memory now. And much like a hoarder, the more space we have to store things, the more things we do store, and the more disorganised it gets. And even if you do clear a spot, the next thing you want to store might not fit there and you end up storing it someplace else. If you end up bouncing around looking for things you end up thrashing the TLB, throwing out cached entries you still need so now need to perform the entire table walk again (Just to invariably throw that result away soon after).

    Basically, you need to defrag your RAM periodically so that the mappings don't get too complex and slow things down (Same is true for SSDs btw, you still need to defrag them to clean up the filesystem metadata itself, just less often than HDDs). Meta have been working on improvements to how Linux handles all this stuff (page table layout and memory compaction) for a while because they were seeing some of their long-lived servers ending up spending about 20% of CPU time simply wasted on doing repetitive walks due to a highly fragmented address space.

  • The RA in RAM stands for random access; there is no seeking necessary.

    Well there is, CPUs need to map virtual addresses to physical ones. And the more RAM you have the more management of that memory you need to do (e.g. modern Intel and AMD CPUs have 5 levels of indirection between a virtual and physical address)

    But it also caches those address mappings, as long as your TLB is happy, you're happy. An alternative is to use larger page sizes (A page being the smallest amount of RAM you can address), the larger the page the less you need recurse into the page tables to actually find said page, but you also can end up wasting RAM if you're not careful.

  • This is what my comment was about. You can’t make social change with super powers. Super powers are a tool of physical force. I’m sure someone could write a great story about a super hero leading a violent and justified revolution, but you can’t possibly expect that to be a hallmark of the genre.

    One of the marvel movies has a line about how Stark Industries is now the world leader in clean energy thanks to his arc reactor, that would have a massive societal impact and upend existing power structures, but it'd also make for a pretty boring film.

    While there would be some people who'd watch RDJ sit in meetings for 2 hours making agreements, it wouldn't be the same amount that'd watch him put on the suit and punch people into orbit.

    Edit: Actually, on the other hand in Secret Invasion ::: spoiler spoiler the US president has the UK prime minster assassinated on live television ::: And even in universe they seem to have glossed over that.

  • Java Bros

  • TypeScript is actually pretty nice, it'd be JScript instead.

  • Yeah, I think Windows actually handles it quite well, the actual filesystem has no notion of what the filenames are outside of basic "It's UTF-16", it's the OS filesystem layer that handles all the quirks.

    Because that's what people seem to dismiss, there's no one standard notion of case folding. It depends on the locale you're using, and that shouldn't be built into the FS itself. The classic one was the German "long S", where "SS" should be case folded with "ß", except they changed it in 2024 so now they shouldn't match ("ß" becomes "ẞ" now), good luck updating your FS to support rules like that.

    Now your shell? That's easy, you can just warn the user that a "matching" filename already exists and prompt them to change it, and you can vary those warnings based on the locale, and you can push out updates as easily as any other patch.

  • Notepad

  • “Literally” is not an exaggeration

    Correct, it's an "intensifier"

  • I remember one of the modders behind a UI overhaul talking about the response to paid mods, when users kept saying that a donation system was better, that in the entire time they'd been making the mod they'd only gotten like $50 in donations total.

    Edit: And seeing modders use patreon now for support, and those mods still getting "pirated", I don't think the issue was ever about Bethesda or how they handled it.

  • insane

  • It is a bit odd.

  • Syngenta has consistently denied any link between paraquat and Parkinson’s, pointing to regulatory reviews in the U.S., Australia and Japan that found no evidence of causality.

    Well I don't know about the US or Japan, but I can trust my government to do the right thing.

    The chief executive confirmed the science underpinning the regulator’s decision rests largely on an earlier report prepared for the APVMA in 2016, which also assessed mice studies linking paraquat to Parkinson’s disease.

    That report acknowledged Dr Cory-Slechta and her co-authors’ findings from 2002 that paraquat caused hallmarks of Parkinson’s in mice that were injected with the chemical.

    But the 2016 report’s authors ultimately dismissed those findings, on the basis that an unpublished paper, funded by Syngenta, could not reproduce them.

    Oh...

  • Yeah, the days of end users installing their own OS is in the past, PCs are appliances for most people now.

  • Figuring out how to more efficiently house/care for a glut of humans farther in the future is way more practical.

    Our government's started means testing care services due to the projected costs and loss of tax income as the population ages and costs increase.

    It doesn't help that the only form of economic management they do is offer tax cuts, they're getting less and less tax out of an already declining share of the population.

  • Yeah I think they're generally regarded as a mistake, browsers have removed all the UI signifying an EV cert these days.

  • moot created the site in response to lowtax banning hentai on Something Awful, I'm not sure I'd call that "innocent"

  • I wish the tooling around Secure Scuttlebutt wasn't so annoying to use, more attention might have had some of the rough edges filed off.

    On one hand you can have an offline first replication method (Phones syncing messages over bluetooth, etc.), but then you can't post from multiple devices without moving your account between them.

  • Permanently Deleted

  • It's also not a progressive JPEG either.

  • I should have and honestly might have, been long enough that I don't remember that aspect.