I'll address your question in two parts: 1) is it redundant to store both the IP subnet and its subnet mask, and 2) why doesn't the router store only the bits necessary to make the routing decision.

Prior to the introduction of CIDR -- which came with the "slash" notation, like /8 for the 10.0.0.0 RFC1918 private IPv4 subnet range -- subnets would genuinely be any bit arrangement imaginable. The most sensible would be to have contiguous MSBit-justified subnet masks, such as 255.0.0.0. But the standard did not preclude using something unconventional like 255.0.0.1.

For those confused what a 255.0.0.1 subnet mask would do -- and to be clear, a lot of software might prove unable to handle this -- this is describing a subnet with 2^23 addresses, where the LSBit must match the IP subnet. So if your IP subnet was 10.0.0.0, then only even numbered addresses are part of that subnet. And if the IP subnet is 10.0.0.1, then that only covers odd numbered addresses.

Yes, that means two machines with addresses 10.69.3.3 and 10.69.3.4 aren't on the same subnet. This would not be allowed when using CIDR, as contiguous set bits are required with CIDR.

So in answer to the first question, CIDR imposed a stricter (and sensible) limit on valid IP subnet/mask combinations, so if CIDR cannot be assumed, then it would be required to store both of the IP subnet and the subnet mask, since mask bits might not be contiguous.

For all modern hardware in the last 15-20 years, CIDR subnets are basically assumed. So this is really a non-issue.

For the second question, the router does in-fact store only the necessary bits to match the routing table entry, at least for hardware appliances. Routers use what's known as a TCAM memory for routing tables, where the bitwise AND operation can be performed, but with a twist.

Suppose we're storing a route for 10.0.42.0/24. The subnet size indicates that the first 24 bits must match a prospective destination IP address. And the remaining 8 bits don't matter. TCAMs can store 1's and 0's, but also X's (aka "don't cares") which means those bits don't have to match. So in this case, the TCAM entry will mirror the route's first 24 bits, then populate the rest with X's. And this will precisely match the intended route.

As a practical matter then, the TCAM must still be as wide as the longest possible route, which is 32 bits for IPv4 and 128 bits for IPv6. Yes, I suppose some savings could be made if a CIDR-only TCAM could conserve the X bits, but this makes little difference in practice and it's generally easier to design the TCAM for max width anyway, even though non-CIDR isn't supported on most routing hardware anymore.

To start off, I'm sorry to hear that you're not receiving the healthcare you need. I recognize that these words on a screen aren't going to solve any concrete problems, but in the interest of a fuller comprehension of the USA healthcare system, I will try to offer an answer/opinion to your question that goes into further depth than simply "capitalism" or "money and profit" or "greed".

What are my qualifications? Absolutely none, whatsoever. Although I did previously write a well-received answer in this community about the USA health insurance system, which may provide some background for what follows.

In short, the USA healthcare system is a hodge-podge of disparate insurers and government entities (collectively "payers"), and doctors, hospitals, clinics, ambulances, and more government entities (collectively "providers"), overseen by separate authorities in each of the 50 US States, territories, tribes, and certain federal departments (collectively "regulators"). There is virtually no national-scale vertical integration in any sense, meaning that no single or large entity has the viewpoint necessary to thoroughly review the systemic issues in this "system", nor is there the visionary leadership from within the system to even begin addressing its problems.

It is my opinion that by bolting-on short-term solutions without a solid long-term basis, the nation was slowly led to the present dysfunction, akin to boiling a frog. And this need not be through malice or incompetence, since it can be shown that even the most well-intentioned entities in this sordid and intricate pantomime cannot overcome the pressures which this system creates. Even when there are apparent winners like filthy-rich plastic surgeons or research hospitals brimming with talented expert doctors of their specialty, know that the toll they paid was heavy and worse than it had to be.

That's not to say you should have pity on all such players in this machine. Rather, I wish to point to what I'll call "procedural ossification", as my field of computer science has a term known as "protocol ossification" that originally borrowed the term from orthopedia, or the study of bone deformities. How very fitting for this discussion.

I define procedural ossification as the loss of flexibility in some existing process, such that rather than performing the process in pursuit of a larger goal, the process itself becomes the goal, a mindless, rote machine where the crank is turned and the results come out, even though this wasn't what was idealized. To some, this will harken to bureaucracy in government, where pushing papers and forms may seem more important that actually solving real, pressing issues.

I posit to you that the USA healthcare system suffers from procedural ossification, as many/most of the players have no choice but to participate as cogs in the machine, and that we've now entirely missed the intended goal of providing for the health of people. To be an altruistic player is to be penalized by the crushing weight of practicalities.

What do I base this on? If we look at a simple doctor's office, maybe somewhere in middle America, we might find the staff composed of a lead doctor -- it's her private practice, after all -- some Registered Nurses, administrative staff, a technician, and an office manager. Each of these people have particular tasks to make just this single doctor's office work. Whether it's supervising the medical operations (the doctor) or operating/maintaining the X-ray machine (technician) or cutting the checks to pay the building rent (office manager), you do need all these roles to make a functioning, small doctor's office.

How is this organization funded? In my prior comment about USA health insurance, there was a slide which showed the convoluted money flows from payers to providers, which I've included below. What's missing from this picture is how even with huge injections of money, bad process will lead to bad outcomes.

Source

In an ideal doctor's office, every patient that walks in would be treated so that their health issues are managed properly, whether that's fully curing the condition or controlling it to not get any worse. Payment would be conditioned upon the treatment being successful and within standard variances for the cost of such treatment, such as covering all tests to rule out contributing factors, repeat visits to reassess the patient's condition, and outside collaboration with other doctors to devise a thorough plan.

That's the ideal, and what we have in the USA is an ossified version of that, horribly contorted and in need of help. Everything done in a doctor's office is tracked with a "CPT/HCPCS code", which identifies the type of service rendered. That, in and of itself, could be compatible with the ideal doctor's office, but the reality is that the codes control payment as hard rules, not considering "reasonable variances" that may have arisen. When you have whole professions dedicated to properly "coding" procedures so an insurer or Medicare will pay reimbursement, that's when we've entirely lost the point and grossly departed from the ideal. The payment tail wags the doctor dog.

To be clear, the coding system is well intentioned. It's just that its use has been institutionalized into only ever paying out if and only if a specific service was rendered, with zero consideration for whether this actually advanced the patient's treatment. The coding system provides a wealth of directly-comparable statistical data, if we wanted to use that data to help reform the system. But that hasn't substantially happened, and when you have fee-for-service (FFS) as the base assumption, of course patient care drops down the priority list. Truly, the acronym is very fitting.

Even if the lead doctor at this hypothetical office wanted to place patient health at the absolute forefront of her practice, she will be without the necessary tools to properly diagnose and treat the patient, if she cannot immediately or later obtain reimbursement for the necessary services rendered. She and her practice would have to absorb costs that a "conforming" doctor's office would have, and that puts her at a further disadvantage. She may even run out of money and have to close.

The only major profession that I'm immediately aware of which undertakes unknown costs with regularity, in the hopes of a later full-and-worthwhile reimbursement, is the legal profession. There, it is the norm for personal injury lawyers to take cases on contingency, meaning that the lawyer will eat all the costs if the lawsuit does not ultimately prevail. But if the lawyer succeeds, then they earn a fixed percentage of the settlement or court judgement, typically 15-22%, to compensate for the risk of taking the case on contingency.

What's particularly notable is that lawyers must have a good eye to only accept cases they can reasonably win, and to decline cases which are marginal or unlikely to cover costs. This heuristic takes time to hone, but a lawyer could start by being conservative with cases accepted. The reason I mention this is because a doctor-patient relationship is not at all as transactional as a lawyer-client relationship. A doctor should not drop a patient because their health issues won't allow the doctor to recoup costs.

The notion that an altruistic doctor's office can exist sustainably under the FFS model would require said doctor to discard the final shred of decency that we still have in this dysfunctional system. This is wrong in a laissez-faire viewpoint, is wrong in a moral viewpoint, and is wrong in a healthcare viewpoint. Everything about this is wrong.

But the most insidious problems are those that perpetuate themselves. And because of all those aforementioned payers, providers, and regulators are merely existing and cannot themselves take the initiative to unwind this mess, it's going to take more than a nudge from outside to make actual changes.

As I concluded my prior answer on USA health insurance, I noted that Congressional or state-level legislation would be necessary to deal with spiraling costs for healthcare. I believe the same would be required to refocus the nation's healthcare procedures to put patient care back as the primary objective. This could come in the form of a single-payer model. Or by eschewing insurance pools outright by extending a government obligation to the health of the citizenry, commonly in the form of a universal healthcare system. Costs of the system would become a budgetary line-item so that the health department can focus its energy on care.

To be clear, the costs still have to be borne, but rather than fighting for reimbursement, it could be made into a form of mandatory spending, meaning that they are already authorized to be paid from the Treasury on an ongoing basis. For reference, the federal Medicare health insurance system (for people over 65) is already a mandatory spending obligation. So upgrading Medicare to universal old-people healthcare is not that far of a stretch,

I know this is c/programmerhumor but I'll take a stab at the question. If I may broaden the question to include collectively the set of software engineers, programmers, and (from a mainframe era) operators -- but will still use "programmers" for brevity -- then we can find examples of all sorts of other roles being taken over by computers or subsumed as part of a different worker's job description. So it shouldn't really be surprising that the job of programmer would also be partially offloaded.

The classic example of computer-induced obsolescence is the job of typist, where a large organization would employ staff to operate typewriters to convert hand-written memos into typed documents. Helped by the availability of word processors -- no, not the software but a standalone appliance -- and then the personal computer, the expectation moved to where knowledge workers have to type their own documents.

If we look to some of the earliest analog computers, built to compute differential equations such as for weather and flow analysis, a small team of people would be needed to operate and interpret the results for the research staff. But nowadays, researchers are expected to crunch their own numbers, possibly aided by a statistics or data analyst expert, but they're still working in R or Python, as opposed to a dedicated person or team that sets up the analysis program.

In that sense, the job of setting up tasks to run on a computer -- that is, the old definition of "programming" the machine -- has moved to the users. But alleviating the burden on programmers isn't always going to be viewed as obsolescence. Otherwise, we'd say that tab-complete is making human-typing obsolete lol

It's also worth noting that switching from ANSI to ISO 216 paper would not be a substantial physical undertaking, as the short-side of even-numbered ISO 216 paper (eg A2, A4, A6, etc) is narrower than for ANSI equivalents. And for the odd-numbered sizes, I've seen Tabloid-size printers in America which generously accommodate A3.

For comparison, the standard "Letter" paper size (aka ANSI A) is 8.5 inches by 11 inches. (note: I'm sticking with American units because I hope Americans read this). Whereas the similar A4 paper size is 8.3 inches by 11.7 inches. Unless you have the rare, oddball printer which takes paper long-edge first, this means all domestic and small-business printers could start printing A4 today.

In fact, for businesses with an excess stock of company-labeled #10 envelopes -- a common size of envelope, measuring 4.125 inches by 9.5 inches -- a sheet of A4 folded into thirds will still (just barely) fit. Although this would require precision folding, that's no problem for automated letter mailing systems. Note that the common #9 envelope (3.875 inches by 8.875 inches) used for return envelopes will not fit an A4 sheet folded in thirds. It would be advisable to switch entirely to A series paper and C series envelopes at the same time.

Confusingly, North America has an A-series of envelopes, which bear no relation to the ISO 216 paper series. Fortunately, the overlap is only for the less-common A2, A6, and A7.

TL;DR: bring reams of A4 to the USA and we can use it. And Tabloid-size printers often accept A3.

That book sounds very insightful. I hope my public library accepts my purchase suggestion.

You are correct: even when you have a live body on the stand about to give testimony, it is essential to lay the foundation as to who they are and their legitimacy. Obviously, if they aren't who they say they are, that's a huge problem. So the party who called the witness will have done their homework in advance, and the opposing lawyers will have been notified in advance of this witness's appearance and conduct their own homework.

For when a person is testifying but they aren't in the room, I understand that there are several requirements that a telepresence system must comply with, both technical and usability. Certainly, someone's visage or image would be preferable to an audio-only phone call. Presumably, the jury needs to trust this witness to believe them or else it's rather pointless. Nowadays, with deep fakes and AI, it could possibly become an issue in future if video appearances in court are actually faked, or if the suggestion becomes plausible due to advancements in the technology.

So if we think of the zombie not as a live body but someone whose presence is being facilitated by the necromancer's abilities, then the necromancer must be quizzed as to the veracity of their abilities, and the court would have to question what limits must be imposed on the testimony to make it admissible.

If it's anything like the bunk science that courts have previously adopted -- bite mark analysis comes to mind -- then it only takes one court to permit necromancy and other courts will point to that one case as precedence. This would only be a problem if the necromancy is flawed in some serious way.

I'm not a lawyer, but let's have some fun with this.

To start, I'm going to have to assume a jurisdiction. I'll go with California, because Hollywood films have depicted a lot of walking dead, zombies, and whatnot. And also because that's the jurisdiction I'm most familiar with. I think that such a case where the undead might be a witness would mostly arise in California state courts, since zombies rarely walk/jump/crawl quickly enough to cross state lines from the major population centers of California, which wokld invoke federal jurisdiction.

Now, we need to hone in on the type of case. A murder case where the victim is called as a witness would certainly be very juicy. But the same legal intrigue would arise from a less-interesting inheritance or family law case. We could also go into contracts and see whether or not the presence of an undead counts as an "act of God" but maybe that's a bit too niche and law-school theoretical.

To really showcase the problems this would pose to the court, we will focus on the undead being witness in a criminal trial, as the standard of proof to convict the defendant would be proof "beyond a reasonable doubt". As the most stringent category of proof, it necessarily follows that the court must err on the side of the defendant in matters of impartiality. This is because the court is technically an arm of the state, and the prosecution wields all the resources of the state against an individual who stands accused of some criminal act.

As such, for criminal trials, there are certain constitutional rights of the defendant that the court must uphold. The foremost is the right to due process, guaranteed by the Fifth and Fourteenth Amendments. One of the results from applying due process is that evidence introduced in a criminal trial must not be "unduly prejudicial". That is, no evidence can be admitted which so irresponsibly causes the jury to render a verdict based on anything but the law.

Often, this rule is invoked to set aside irrelevant evidence which has no bearing on the charges, except maybe to impugn the reputation of the defendant so that the jury thinks they're a terrible person. Other times, it can be used to exclude relevant but really-bad evidence. The US courts have been through cycles where novel science is used in a prosecution but which later turns out to be bunk and lacking any foundation in reality. It certainly is "evidence" but because it purports to be science when it's really not, it must be excluded. Psychics are certainly not going to be welcomed witnesses as a subject matter expert.

Finally, the other category for evidence being unduly prejudicial is when the jury -- through no fault of their own -- would weigh that evidence as being the primary factor, above all else, whether it's DNA or video evidence. This is more a matter of testimony evidence rather than physical evidence. Imagine a small, devoutly religious town where the local pastor is called to testify about whether the defendant could have committed hit-and-run.

Having a respected community authority figure testify about someone's potential to commit a crime might be something the jury members would be open to hearing, but the judge might have to weigh whether the fact that the lay witness is a pastor will cause the jury to put too much weight on that testimony, even though the pastor is no more able to weigh someone's character than some other member of the community. If there are other ways to obtain the same evidence -- such as bringing in the defendant's mother or employer -- the judge should not allow the pastor to testify, because it could jeopardize the soundness of the trial and lead to an appeal.

So now we come back to zombies. Would a jury be able to set aside their shock, horror, and awe about a zombie in court that they could focus on being the finder of fact? If a zombie says they're an eye-witness to a mugging, would their lack of actual eyeballs confuse the jury? Even more confusing would be a zombie that is testifying as an expert witness. Does their subject matter need to be recent? What if the case needs an expert on 17th Century Parisian fashion and the undead is from that era and worked in haute couture? Are there no fashion historians who could provide similar expert opinions?

But supposing we did overcome all that, there might be one form of testimony which -- even though very prejudicial -- might be allowable for a lay-witness (ie not expert) zombie witness to testify about, and I already mentioned it earlier.

In most jurisdictions and in California, a dying person's last act which might point to their killer will not necessarily be excluded for being irrelevant or being circumstantial. It is a rebuttable presumption that someone dying has no incentive to lie, and will likely have been the final witness to their own murder.

To that end, it's entirely plausible that a zombie who died by murder could come to court to testify against their killer. Of course, how long does it take for the dead to become undead? If this takes longer than the statue of limitations allows (note: California has no limits for charging murder), the defendant would walk. Likewise, if the zombie's testimony is the only shred of evidence for the murder, that's not likely to convince the jury. Not unless, of course, the details of the testimony match the circumstances of the crime so well that it wasn't a fluke.

TL;DR: rules of evidence would still apply to the undead, and judges must take care to balance the probative value of evidence with any prejudicial quality it may carry.

(to be abundantly clear, this was a schittpost lol)

I will admit that my familiarity with private law outside the USA is almost non-existent, except for what I skimmed from the Wikipedia article for the Inquisitorial system. So I had assumed that private law in European jurisdictions would follow the same judge-intensive approach. Rereading the article more closely, I do see that it really only talks about criminal proceedings.

But I did some more web searching, and found this -- honestly, extremely convenient -- article comparing civil litigation procedure in Germany and California (the jurisdiction I'm most familiar with; IANAL). The three most substantial differences I could identify were the judge's involvement in: serving papers, discovery, and depositions.

Serving legal notice is the least consequential difference between California and Germany, but it seems that the former allows any qualified adult to chase down the respondent (ie person being sued) and deliver the notice of a lawsuit -- hence the trope of yelling "you have been served" and then throwing a stack of papers at someone's porch -- on behalf of the complainant (person who filed the lawsuit). Whereas German courts take up the role themselves for notifying the complainant. Small difference, but notable.

In Germany, the court, and not the plaintiff, is required to serve the complaint on the defendant without undue delay, which is usually immediately after it has been filed with the court.

Next, discovery and pleadings in Germany appear to be different from the California custom. It seems that German courts require parties to thoroughly plead their positions first, and only afterwards will discovery begin, with the court deciding what topics can be investigated. Whereas California allows parties to make broad assertions that can later be proven or disproven during discovery. This is akin to throwing spaghetti at the wall and seeing what sticks, and a big reason this is done is because any argument that isn't raised during trial cannot be reargued during a later appeal.

I believe that discovery in California and other US States can get rather invasive, as each party's lawyers are on a fact-finding mission where the truth will out. The general limitation on the pleadings in California is that they still must be germane to the complaint and at least be colorable. This obviously leads to a lot of pre-trial motions, as the targeted party will naturally want to resist a fishing expedition during discovery.

Lastly, depositions in Germany involve the judge(s) a lot more than they would in California. Here, depositions are off-site from the court and conducted by the deposing party, usually video-taped and with all attorneys present, plus a privately hired stenographer, with the deposing attorney asking questions. Basically, after a deposition order is granted by the judge, the judge isn't involved unless during the deposition, the process is interrupted in a way that would violate the judge's order. But the solution to that is to simply phone the judge and ask for clarification or a new order to force the deposition to continue.

Whereas that article describes the German deposition process as always occuring in court, during trial, and with questions asked by the judge(s). The parties may suggest certain questions by way of constructing arguments which require the judge(s) to probe in a particular direction. But it's not clear that the lawyers get to dictate the exact questions asked.

In contrast, depositions in Germany are conducted by the judge or the panel of judges and only during trial.

I grant you that this is just an examination of the German court proceedings for private law. And perhaps Germany may be an outlier, with other European counterparts adopting civil law but with a more adversarial flavor for private law. But I would say that for Germany, these differences indicate that their private law is more inquisitorial overall, in stark contrast to the California or USA adversarial procedure for private litigation.

Lasers work really well in space for secure sat-to-sat data links, but are a lot less viable on Earth's surface due to diffraction and weather, nevermind the limits of the visible horizon for any height of a communications tower. For pretty much any scenario where laser comms would be considered, microwave RF links would likely be just as good, cheaper, and more commonly deployed and understood by telecom engineers. The only exception is when absurdly high bandwidths are needed, which is where lasers rule.

But using RF links across thousands of kilometers of oceanic waters? For that, you must construct additional pylons on floating islands to repeat the signal. Otherwise, the only RF signals that could reach land would be too low frequency to carry much bandwidth.

For reference, when the German Aerospace Center (DLR) set the world record in 2016 for free-space optical communications, they achieved 1.72 Tbits/sec over a distance of 10.45 km. Most optical systems observe a bandwidth/distance relationship, where at best, shooting the signal farther means less available bandwidth, or more bandwidth if brought closer. This is a related to the Shannon-Hartley theorem, since the limiting factor is optical noise.

So if 1.72 Tbits/sec at 10 km is the best they achieved in free air in 2016, then that pales in comparison to the undersea fibre cables of 2006, where a section of the SHEFA-2 Scottish-Faroese cable runs unamplified for 390 km and moves 570 Gbits/sec aggregate.

In short, free-space lasers are fast and long-distance. But lasers within fibre cables are much faster and cover even longer distances. They're not even in the same league.

You are absolutely correct: this fragile experiment called democracy will not survive if the citizenry becomes ambivalent about its institutions, allowing corrupt officials and other enablers of authoritarianism to take root.

If you are an American and that prospect disturbs you, then you need to help strengthen and guard the institutions that protect the core American values. Nobody owes you a democracy.

For some ideas of what to do, this post by Teri Kanefield has a list of concrete actions that you can take: https://terikanefield.com/things-to-do/

I am usually not wont to defend the dysfunction presently found in the USA federal (and state-level) judiciary, but I think this comparison to the German courts requires a bit more context. Generally speaking, the USA federal courts and US States adopt the adversarial system, originally following the English practice in both common law and equity. This means the judge takes on a referee role, and a plaintiff and a defendant will make their best, most convincing arguments.

I should clarify that "common law" in this context refers to the criminal matters (akin to public law), and "equity" refers to person-versus-person disputes (akin to private law), such as contracts.

For the adversarial system to work, the plaintiff and defendant need to be sufficiently motivated (and nowadays, well-monied) to put on good arguments, or else they're just wasting the court's time. Hence, there is a requirement (known as "standing") where -- grossly oversimplifying -- the plaintiff must be the person with the most to gain, and the defendant must be the person with the most to lose. They are interested parties who will argue vigorously.

Of course, that's legal fiction, because oftentimes, a defendant might be unable to able to afford excellent legal counsel. Or plaintiffs will half-ass or drag out a lawsuit, so that it's more an annoyance to the opposite party.

In an adversarial system, it is each party's responsibility to obtain subject-matter experts and their opinions to present to the court. The judge is just there to listen and evaluate the evidence -- exception: criminal trials leave the evaluation of evidence to the jury.

Why is the USA like this? For the USA federal courts, it's because it's part of our constitution, in the Case or Controversy Clause. One of the key driving forces for drafters of the USA Constitution was to restrict the powers of government officials and bureaucrats, after seeing the abuses committed during the Colonial Era. The Clause above is meant to constrain the unelected judiciary -- which otherwise has awe-inducing powers such as jailing people, undoing legislation, and assigning wardship or custody of children -- from doing anything unless some controversy actually needed addressing.

With all that history in mind, if the judiciary kept their own in-house subject-matter experts, then that could be viewed as more unelected officials trying to tip the scale in matters of science, medicine, computer science, or any other field. Suddenly, landing a position as the judiciary's go-to expert could have broad reaching impacts, despite no one in the federal judiciary being elected.

In a sense, because of the fear of officials potentially running amok, the USA essentially "privatizes" subject matter experts, to be paid by the plaintiff or defendant, rather than employed by the judiciary. The adversarial system is thus an intentional value judgement, rather than "whoopsie" type of thing that we walked into.

Small note: the federal executive (the US President and all the agencies) do keep subject matter experts, for the limited purpose of implementing regulations (aka secondary legislation). But at least they all report indirectly to the US President, who is term-limited and only stays 4 years at a time.

This system isn't perfect, but it's also not totally insane.

Can you please kindly link to that article, if it's publicly available?