lisper

45 ms·

781.
by lisper 2y ago
Like everything in computer security, it's complicated, and there are tradeoffs. First, intercepting SMS is not that easy. It's "easy" for someone who knows what they are doing and is willing to expend some resources,
782.
by lisper 2y ago
Only a naive implementation requires infinite memory. (And even then it's unbounded, not infinite.)
783.
by lisper 2y ago
> he does not have an answer Well, yeah. That's the whole point.
784.
by lisper 2y ago
Richard Feynman gave what I consider to be the best possible answer to questions like this: https://www.youtube.com/watch?v=Q1lL-hXO27Q
785.
by lisper 2y ago
> Delivery is what happens when the signals cross from the wire into the network interface card. If you look at this sibling comment [1] you will find someone who disagrees with your definition. [1] https://news.ycombinator.co
786.
by lisper 2y ago
But I don't disagree with that definition. The only thing in dispute is whether or not it is possible to achieve. It seems clear to me that it is possible, but for some reason that I still don't understand people keep insisting
787.
by lisper 2y ago
> I am not interested in talking to you anymore. Then why do you keep doing it?
788.
by lisper 2y ago
> considering something at the end of a fault-free channel as the element of the distributed system being delivered to is silly. That may be, but that's a different discussion. "Silly" and "impossible" are not s
789.
by lisper 2y ago
> To discard the duplicates, you need to update your state based on the first message and consult that state for all subsequent messages. Someone must be delivered those messages for this to happen. Yes, that's right. > If you sa
790.
by lisper 2y ago
What you call "technical minutiae" I call "the meanings of words", which is very germane to the matter of human communication.
791.
by lisper 2y ago
> if the deduplication isn't atomic with the application's actions, incorrect behavior results So? What do the application requirements have to do with the question of whether or not exactly-once delivery is possible? The app
792.
by lisper 2y ago
> An element of a distributed system that wants to debit from bank accounts must acknowledge the receipt of a message after making its effects durable. I do not and never have disputed that. But I fail to see what that has to do with t
793.
by lisper 2y ago
> you're insistent on calling them different entities so that you can win an internet argument No, I'm insistent on calling them different entities because in actual practice they can be, and indeed usually are, different entit
794.
by lisper 2y ago
> The guards have "processed" the message for this purpose, and the fact that they can deliver it to you over a perfectly reliable channel is moot. No, it isn't, because the situation inside the fort is different than the
795.
by lisper 2y ago
> You are especially well-answered here I don't see anything there that is at odds with anything I have said. All I see there is a restatement of my position. > One reason the delivery / processing distinction exists becaus
796.
by lisper 2y ago
I don't have any hangups about how other people feel about anything. My "hangup" is that I see no evidence that there is a consensus on a technical definition of the word "delivery". In the absence of such a defin
797.
by lisper 2y ago
Thank you for that link! You just saved me a lot of time reinventing that wheel.
798.
by lisper 2y ago
> solved without constraints on time window, msgs rates and msgs sizes But that is not what I am claiming.
799.
by lisper 2y ago
Really? That is what causes you to question whether or not I'm acting in good faith? If that's what you call "calling people out by name" I guess we'll just have to agree to disagree.
800.
by lisper 2y ago
> You're calling people out by name I am? Where? > Getting "exactly once" processing usually requires making various kinds of resilience tradeoffs based on timing windows, storage requirements, etc Yes, of course. Bu
801.
by lisper 2y ago
I'm not asking for a debate. I'm simply asking you to tell me what "exactly once delivery" actually means in a way that isn't circular and doesn't beg the question of whether or not it is possible, i.e. the de
802.
by lisper 2y ago
The kind of reliability I'm talking about where "100% reliable" is a reasonable assumption is inside the boundaries of a single server, i.e. a CPU, memory bus, and I/O peripherals including a NIC and non-volatile storage
803.
by lisper 2y ago
As you have described it, you are right, it's not. But presumably the thing discarding the duplicates then does something with the non-duplicates, like deliver then to something else. That is exactly-once delivery.
804.
by lisper 2y ago
Thanks.
805.
by lisper 2y ago
Yeah, but that just seems like a bizarre definition on which to base the claim that you cannot have exactly-once delivery. Obviously, if you define delivery to preclude de-duplication, then you can't have exactly-once delivery. B
806.
by lisper 2y ago
> if you have received duplicate messages then by definition you have been delivered that message more than once Yes. So? If you don't include a mechanism for ensuring exactly-once delivery then you will not be guaranteed exactly-
807.
by lisper 2y ago
Yes, that's true, but that's often a reasonable assumption.
808.
by lisper 2y ago
> It seems like this person does not understand what exactly once delivery actually means. Then by all means, enlighten me.
809.
by lisper 2y ago
> the handoff can fail in the same way Everything in a digital system can fail, but by convention (and because it's not so far from the actual truth) some parts are assumed to be 100% reliable when modeling them. If you don't
810.
by lisper 2y ago
I disagree. If I'm an actual general in a fort with a gate, and I tell the gate guards to inspect messages brought in by couriers and not allow couriers carrying duplicate messages to enter, the ones that the guards let through are st

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