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Cake day: July 2nd, 2023

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  • C, C++, C#, to name the main ones. And quite a lot of languages are compiled similarly to these.

    To be clear, there’s a lot of caveats to the statement, and it depends on architecture as well, but at the end of the day, it’s rare for a byte or bool to be mapped directly to a single byte in memory.

    Say, for example, you have this function…

    public void Foo()
    {
        bool someFlag = false;
        int counter = 0;
    
        ...
    }
    

    The someFlag and counter variables are getting allocated on the stack, and (depending on architecture) that probably means each one is aligned to a 32-bit or 64-bit word boundary, since many CPUs require that for whole-word load and store instructions, or only support a stack pointer that increments in whole words. If the function were to have multiple byte or bool variables allocated, it might be able to pack them together, if the CPU supports single-byte load and store instructions, but the next int variable that follows might still need some padding space in front of it, so that it aligns on a word boundary.

    A very similar concept applies to most struct and object implementations. A single byte or bool field within a struct or object will likely result in a whole word being allocated, so that other variables and be word-aligned, or so that the whole object meets some optimal word-aligned size. But if you have multiple less-than-a-word fields, they can be packed together. C# does this, for sure, and has some mechanisms by which you can customize field packing.







  • The REAL problem is that the industry collectively uses JS almost exclusively for shit it was never meant to do. Like you say, it’s intended for it to not throw errors and kill your whole web page, because it was only ever intended to be used for minor scripts inside mostly-static HTML and CSS web pages. Then we all turned it into the most-popular language in the world for building GUI applications.








  • It’s the capability of a program to “reflect” upon itself, I.E. to inspect and understand its own code.

    As an example, In C# you can write a class…

    public class MyClass
    {
        public void MyMethod()
        {
            ...
        }
    }
    

    …and you can create an instance of it, and use it, like this…

    var myClass = new MyClass();
    myClass.MyMethod();
    

    Simple enough, nothing we haven’t all seen before.

    But you can do the same thing with reflection, as such…

    var type = System.Reflection.Assembly.GetExecutingAssembly()
        .GetType("MyClass");
    
    var constructor = type.GetConstructor(Array.Empty<Type>());
    
    var instance = constructor.Invoke(Array.Empty<Object>());
    
    var method = type.GetMethod("MyMethod");
    
    var delegate = method.CreateDelegate(typeof(Action), instance);
    
    delegate.DynamicInvoke(Array.Empty<object>());
    

    Obnoxious and verbose and tossing basically all type safety out the window, but it does enable some pretty crazy interesting things. Like self-discovery and dynamic loading of plugins, or self-configuration of apps. Also often useful when messing with generics. I could dig up some practical use-cases, if you’re curious.


  • Generally speaking, fault protection schemes need only account for one fault at a time, unless you’re a really large business, or some other entity with extra-stringent data protection requirements.

    RAID protects against drive failure faults. Backups protect against drive failure faults as well, but also things like accidental deletions or overwrites of data.

    In order for RAID on backups to make sense, when you already have RAID on your main storage, you’d have to consider drive failures and other data loss to be likely to occur simultaneously. I.E. RAID on your backups only protects you from drive failure occurring WHILE you’re trying to restore a backup. Or maybe more generally, WHILE that backup is in use, say, if you have a legal requirement that you must keep a history of all your data for X years or something (I would argue data like this shouldn’t be classified as backups, though).