I'm out of the loop. Is there any context? Can't pick up on what really changed here.
236 karma · joined November 10, 2022
Blog: https://blog.leonbecker.de
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I know its never as easy as just do this, this and that and everything will work out fine. I wish you the best.
1. Is answered in the parent comment
2. It's not really about solving problems directly. Its more about a common way to hold meta information about your data. But of course that might help you with approaching similar problems.
3. Thats hard. You dont really think about it that way. Again its not really the type of problems directly. Its more about similar approaches to solving different kinds of problems. So you can use monads for solving basically any problem. But you can also choose to not use monads to solve the problem. This is something you'll need to get a feel for. And it shouldn't be for first line of thought. When solving a problem you might recognize that a certain monad lends itself to solving the problem. But it's not really something you actively go looking for.
This is how "side effect" information is carried outside the actual information the monad is carrying. Real side effects like writing to disk however are not real monads. The IO monad pretends to be a real monad but it's not. It just helps with hiding the impurity of IO from the pure parts of Haskell.
So one might think about the IO monad kind of like the list monad where the order of the IO operations is encapsulated. It kind of pretends that the IO part is pure and deterministic when its actually not in order to have a somewhat clean separation between pure and non pure parts of the program.
Hope that helps.
A monad is kind of like a generic class to boxes that adds additional logic to the data it boxes without actually caring about the data itself.
My goto monad for that concept is a linked list and the map operator. So an instance of the linked list might be Node(5) -> Node(7) -> EmptyList. Now let's call map with a function f(x) = str(x) + " * 2 = " + str(2x). This gives us Node("5 2 = 10") -> Node("7 * 2 = 14") -> EmptyList.
Now let's separate the monad from this. The monad is the structure and logic around the data and the function that we provide. The monad doesn't care what data it holds and is doesn't care what function we provide. It only defines the structure and how functions are applied to the data it holds.
You actually said it yourself in your comment: "not everyone can deal with AWS, nor can everyone edit a website." Stelae is for the second group, the WordPress-editor side, who don't want to run public PHP to publish. The €19.90 isn't margin on the hosting; the hosting is yours, on whatever provider you pick.
For example in a distributed event based LAN chat, I used MD5 for an "integrity chain". Every new event id is the hash of the old event id + some random bytes. This way you can easily find the last matching event two systems have in common. Just a random id isn't enough, when two instances integrate an event from a third system, while one of the two added a new event just before that.
No security needed, speed doesn't matter much, it is not designed for high throughput. MD5 seems like a very good choice, because it's easy to work with and can be verified on every system.
And I don't think that is enough. I agree that it easier and sufficient for most systems to just be connected over the internet. But health, aviation and critical infrastructure in general should try to be offline as much as possible. Many of the issues described with being offline stem from having many third party dependencies (which typically assume internet access). In general but for critical infrastructure especially you want as little third party dependencies as possible. Sure it's not as easy as saying "we don't want third party dependencies" and all is well. You'll have to make a lot of sacrifices. But you also have a lot to gain when dramatically decreasing complexity, not only from a security standpoint. I really do believe there are many cases where it would be better to use a severely limited tech stack (hardware and software) and use a data diode like approach where necessary.
One of the key headaches mentioned when going offline is TLS. I agree and I think the solution is to not use TLS at all. Using a VPN inside the air-gapped network should be slightly better. It's still a huge headache and you have to get this right, but being connected to the internet at all times is also a HUGE headache.
I used to struggle with this too, but now I look at it this way: you're always at risk of being breached when connecting to the Internet (zero days in Browser, Router, maybe IoT devices on the local network, supply chain attack of some installed software, router, ...). Everything you add to your system/network adds attack surface. But: somewhat popular github projects are usually low risk, because 1) enough people are looking into it to be reasonably sure there's nothing funny in the code base, 2) it's not big enough to be an instetesting targeted for malicious actors.
I think a big part of why it feels scary is the unpredictability you mention. You don't know how you would be compromised and whether you would even notice. Sure you could get comprised and then spread the infection, but it's extremely hard to build malware like that. The much more likely scenario is the that the malware tries to steal crypto or encrypts your files. The chances that something really bad would happen are very slim (Do you even have large amounts of crypto? Do you not have any backups of important files?). In the end that's just a risk you'll have to live with (when connecting to the Internet) just like you're at risk of getting hit by a car when going outside.
This sounds like a pretty big negative to me