My guess is that reading tomes like this is useful as a vocal exercise and can be a way of “getting one’s name out” for aspiring vocal talent. After all, what better way to showcase voice work on a resume than to point to examples online? As for the exact tome, it doesn’t really matter for this purpose but might as well also contribute to the wealth of human media.

When I see “Xitter”, I think it might be pronounced Exeter, like the town in southwest England. But that feels like an undeserved slight against the good people of Devon and England.

So far as I’m aware, non-occupational pre-nominal honorifics inure to the individual, so generally speaking, if that person doesn’t want to use their title, they don’t have to. And in the same way that most people will go along with someone’s acquired honorific of Dr or Capt or whatever, the same should also apply if someone expressed that their honorific should not used. I have no citation for this, other than what I’ve seen in life.

As a sidenote, in Britain, I understand that medical doctors are able to use the pre-nominal of Dr, but surgeons specifically will drop the Dr and just use Mr. or Ms.

Apparently this stems from ages ago when surgeons did not have to have a medical degree, and the doctoral view was that surgeons were akin to butchers. This may have reflected the crudeness of early surgeries. As a result, surgeons developed a history of being Mr – it’s not clear if female surgeons also took on Mr. So after the various laws/rules changed so that surgeons also had to be medically qualified, they still kept the tradition of Mr.

Thus, a male student of medicine in the UK could go from Mr, graduate to Dr, and then graduate as a surgeon to Mr again. I have no citation for this either, but it’s plausible for the ardently traditional British nation.

If you were to properly consider the problem the actual cost would be determined by cost per distance traveled and you essentially decide the distance by which ever you are budgeted for.

I wrote my comment in response to the question, and IMO, I did it justice by listing the various considerations that would arise, in the order which seemed most logical to me. At no point did I believe I was writing a design manual for how to approach such a project.

There are much smarter people than me with far more sector-specific knowledge to “properly consider the problem” but if you expected a feasibility study from me, then I’m sorry to disappoint. My answer, quite frankly, barely arises to a back-of-the-envelope level, the sort of answer that I could give if asked the same question in an elevator car.

I never specified that California would be the best place to implement this process.

While the word California didn’t show up in the question, it’s hard to imagine a “state on the coast” with “excess solar” where desalination would be remotely beneficial. 30 US States have coastlines, but the Great Lakes region and the Eastern Seaboard are already humid and wet, with rivers and tributaries that aren’t exactly in a drought condition. That leaves the three West Coast states, but Oregon and Washington are fairly well-supplied with water in the PNW. That kinda leaves California, unless we’re talking about Mexican states.

I’m not dissing on the concept of desalination. But the literature for existing desalination plant around the world showcases the numerous challenges beyond just the money. Places like Israel and Saudi Arabia have desalination plants out of necessity, but the operational difficulties are substantial. Regular clogging of inlet pipes by sealife is a regular occurrence, disposal of the brine/salt extracted is ecologically tricky, energy costs, and more. And then to throw pumped hydro into this project would make it a substantial undertaking, as dams of any significant volume are always serious endeavors.

At this point, I feel the question is approaching pie-in-the-sky levels of applicability, so I’m not sure what else I can say.

I’m not a water or energy expert, but I have occasionally paid attention to the California ISO’s insightful – while perhaps somewhat dry – blog. This is the grid operator that coined the term “duck curve” to describe the abundance of solar energy available on the grid during the daylight hours, above what energy is being demanded during those hours.

So yes, there is indeed an abundance of solar power during the daytime, for much of the year in California. But the question then moves to: where is this power available?

For reference, the California ISO manages the state-wide grid, but not all of California is tied to the grid. Some regions like the Sacramento and Los Angeles areas have their own systems which are tied in, but those interconnections are not sufficient to import all the necessary electricity into those regions; local generation is still required.

To access the bulk of this abundant power would likely require high-voltage transmission lines, which PG&E (the state’s largest generator and transmission operator) operates, as well as some other lines owned by other entities. By and large, building a new line is a 10+ year endeavor, but plenty of these lines meet up at strategic locations around the state, especially near major energy markets (SF Bay, LA, San Diego) and major energy consumers (San Joaquin River Delta pumping station, the pumping station near the Grapevine south of Bakersfield).

But water desalination isn’t just a regular energy consumer. A desalination plant requires access to salt water and to a freshwater river or basin to discharge. That drastically limits options to coastal locations, or long-distance piping of salt water to the plant.

The latter is difficult because of the corrosion that salt water causes; it would be nearly unsustainable to maintain a pipe for distances beyond maybe 100 km, and that’s pushing it. The coastal option would require land – which is expensive – and has implications for just being near the sea. But setting aside the regulatory/zoning issues, we still have another problem: how to pump water upstream.

Necessarily, the sea is where freshwater rivers drain to. So a desalination plant by the ocean would have to send freshwater back up stream. This would increase the energy costs from exorbitant to astronomical, and at that point, we could have found a different use for the excess solar, like storing it in hydrogen or batteries for later consumption.

But as a last thought experiment, suppose we put the plant right in the middle of the San Joaquin River Delta, where the SF Bay’s salt water meets the Sacramento River’s freshwater. This area is already water-depreased, due to diversions of water to agriculture, leading to the endangerment of federally protected species. Pumping freshwater into here could raise the supply, but that water might be too clean: marine life requires the right mix of water to minerals, and desalinated water doesn’t tend to have the latter.

So it would still be a bad option there, even though power, salt water, and freshwater access are present. Anywhere else in the state is missing at least one of those three criteria.

My recommendation is to start with getting fax to work locally. As in, from port 1 of a single SPA2102 to port 2 of the same. This would validate that your fax machines and the SPA2102 is operational, and is just entertaining in its own right to have a dialtone that “calls” the other port.

Fortunately, Gravis from the Cathode Ray Dude YouTube channel has a writeup to do exactly that, and I’ve personally followed these steps on an SPA122 with success, although I was doing a silly phone project, not fax project. https://gekk.info/articles/ata-config.html

If you’re lucky, perhaps fax will Just Work because your machines are very permissive with the signals they receive and can negotiate. If not, you might have to adjust the “fax optimizations” discussed here: https://gekk.info/articles/ata-dialup.html

And then once local faxing works, you can then try connecting two VoIP devices together over the network. This can be as simple as direct SIP using IP and port number, or can involve setting up a PBX that both devices register against.

On one hand, I’m pleased that C++ is answering the call for what I’ll call “safety as default”, since as The Register and everyone else since pointed out, if safety constructs are “bolted on” like an afterthought, then of course it’s not going to have very high adoption. Contrast this to Rust and its “unsafe” keyword that marks all the places where the minimum safety of the language might not hold.

On the other hand, while this Safe C++ proposal adopts a similar notion of an “unsafe” context, it also adds a “safe” keyword, to specify that a function will conform to compile-time safety checks. But as the proposal readily admits:

Rust’s functions are safe by default. C++’s are unsafe by default.

While the proposal will surely continue to evolve before being implemented, I forsee a similar situation as in C where code that lacked initial const-correctness will struggle to work with newer code and libraries. In this case, it would be the “unsafe” keyword that proliferates everywhere just to call older, unsafe code from newer, safe callers.

Rust has the advantage that there isn’t much/any legacy Rust to upkeep, and that means the volume of unsafe code in Rust proframs is minimal, making them safer overall today. But for Safe C++ code, there’s going to be a lot of unsafe legacy C++ code and that reduces the safety benefit for programs overall, for the time being

Even as this proposal progresses, the question of whether to start rewriting some code anew in Rust remains relevant. But this is still exciting as a new option to raise the bar in memory safety in C++.

Haha, your reply beat out mine by only a minute.

This does not agree with what the Social Security Administration has published:

Q20: Are Social Security numbers reused after a person dies?

A: No. We do not reassign a Social Security number (SSN) after the number holder’s death. Even though we have issued over 453 million SSNs so far, and we assign about 5 and one-half million new numbers a year, the current numbering system will provide us with enough new numbers for several generations into the future with no changes in the numbering system.

For the historical questions, I don’t really have answers, especially where it involves departures from the Western world. I did, however, briefly touch up on Islamic banking, which I’ve always found intriguing as the Islamic faith does not permit charging interest on loans, viewing it as usurious. I’m informed that Christianity also had a similar prohibition on usury, but apparently it fell due to the need to fund the constant wars in Europe.

I’m not really seeing the difference in feudalism except a members only kind of participation with a crony pool of inbreds, not all that different than the billionaires of today.

I think the important distinction insofar as stock markets is that the crony pool of inbreds have access, but so too does the commoner. Well, the middle-class commoner usually. And we’ve seen David-vs-Goliath cases where the commoners put up a decent fight against the inbreds’ institutions; the whole GameStonk fiasco comes to mind. An equivalent economic upset would have been wholly impossible at any point during any feudal period in history.

What are the idealist or futurist potential alternatives between the present and a future where wealth is no longer the primary means of complex social hierarchical display? My premise is that basing hierarchical display on the fundamental means of human survival is barbaric primitivism.

From conversations I’ve had previously, possible answers to that question are presented in the works of Paul Cockshott, author of Towards A New Socialism. I’ve not read it, but friends in Marxist-Leninist parties have mentioned it. The Wikipedia page, however, notes that it’s an economics book, which could be fairly technical and difficult to read. Sort of like how Das Kapital is more-or-less a textbook, in contrast with how Wage Labour And Capital was meant for mass consumption.

Wealth extraction neglects the responsibility of the environment and long term planning.

True. The cost to the environment is not “internalized”, to use the technical term. Hence, it doesn’t need to be paid for, and is thus “free real estate”. Solutions to internalize environmental harm include carbon taxes or cap-and-trade. But the latter is a lukewarm carbon tax because it only looks at the end-result emissions, rather than taxing at the oil well, so to speak.

I’m curious how humanity evolves in a distant post scarcity future but without becoming authoritarian or utopian/dystopian

Might I recommend The Three-Body Problem and the trilogy overall by Liu Cixin? This phenomenal hard scifi work describes a space-faring future where the human species faces a common, external threat. After all, much of today’s progress was yesterday’s scifi. So why not look to scifi to see what tomorrow’s solutions might be. It’s no worse than my crystal ball, which is foggy and in need of repair.

If you’re in the USA, I cannot understate how useful it may be to refer to the US Bureau of Labor Statistics’s (BLS) Occupational Outlook Handbook (OOH), a resource which I believe has no direct comparison:

How can I learn about an occupation that is of interest to me?

The Occupational Outlook Handbook (OOH) provides information on what workers do; the work environment; education, training, and other qualifications; pay; the job outlook; information on state and area data; similar occupations; and sources of additional information for more than 300 occupational profiles covering about 4 out of 5 jobs in the economy.

As for answering the question, anecdotal conversations I’ve had suggest that the trades (eg glazier, electrician, plumber) in the USA are promising fields, since while the nature of the job might change with different needs, people still require electric wires and piped water. But the OOH could give you more specific outlooks for those specific trades.

I was once told that plumbers can make very serious sums of money, even if they’re only ever installing supply-side piping. That is to say, the plumbing for water supply, as compared to drainage or sewer pipe, which are generally perceived as less appealing.

I’ll take a shot from the hip at this question, but note that I won’t add my customary citations or links.

The stock market is the paragon of property and trusts, contracts, corporations and law, and the capitalist socio-economic system. The very existence of the stock market implies a society that has some or most of these concepts.

For example, for shares to be traded, there generally must exist ownership rights upon the shares, distinct from the ownership rights that the company has of its own property. Or if not outright ownership of a share, then the benefit that a share provides (eg dividends). It also implies a legal system that will enforce these rights and the obligations of the company to its shareholders.

For a tradable company to exist, it must be organized/chartered as an entity distinct from any single person. This is different than the feudal days, when ventures would be undertaken “in right of the King” or some member of the nobility. The feudal method wouldn’t work for modern companies, or else the King/Duke/Count/whatever could stiff the shareholders by just taking all the earnings. The company still needs to be created by legal means, either an Act of Parliament/Congress, by letter patent from the Monarch, or the modern administrative method of applying to the state Secretary of State (USA) or Companies House (UK) as examples.

Even the structure of a for-profit tradeable company – when compared to a state-owned enterprise, a non-profit, a co-op, or an NGO or QUANGO – is a representation of the values inherent to capitalism. A company is obliged to use the shareholders’ funds – which is held by the company but is owed to the shareholders – to extract the greatest return. But this can come in many forms.

Short-term value from buying investments and quickly flipping them (eg corporate home buyers) is different than rent-seeking (eg corporate landlords) and is still different than long-term investments that actively work to build up the value (eg startup incubators, private wealth funds, Islamic banking, transit-owned adjacent property). If a for-profit company doesn’t have a plan to extract a return… they’re in hot water with the shareholders, with penalties like personal liability for malfeasance.

Another way of looking at the stock market is that if you have all the underlying components but don’t yet have a stock market, it would soon appear naturally. That is to say, if the public stock markets were banned overnight, shares would still trade but just under the table and without regulation. But if any critical part underpinning the markets stopped existing, then the market itself would collapse.

History shows numerous examples where breakdowns of the legal system resulted in market mayhem, or when corporate property is expropriated for the Monarch’s wars or personal use, or when funds invested into or paid out of companies is hampered by terrible monetary inflation.

As for what the stock market does, its greatest purpose is to organize investments into ventures. Historically, ventures were things like building a ship to sail to the New World and steal obtain goods to sell at home. Merchant ships were and are still very expensive, so few singular persons could afford it. And even if the could, the failure of the venture could be catastrophic for that person’s finances. Better to spread the risk and the reward amongst lots of people.

What was once the sole domain of the landed gentry and nobility, slowly opened to the nouveau riche during the Industrial Revolution(s), then in turn to everyday people… for better or worse. It’s now almost trivial to buy a share in any particular listed company, but just opening the stock market to everyone would have been chaotic at best. I think it’s NYSE that still has on-floor traders/brokers, but imagine if all shares in that market had to be traded in a single room, with no digital trading. It’s already quite lively on the trading floor today, now add all the trades from middle class Americans on payday. It would become physically impossible.

Likewise, a pure capitalist stock market would permit awful things like bribing journalists to write fake stories to crash a stock, then buy it for cheap. Or pump and dump scams. And would have no “circuit breakers” that halt a share during so-called flash crashes.

I’m reminded of a scene from the ITV show Agatha Christie’s Poirot in the episode “Appointment With Death”, where a wealthy woman is not only murdered but her business empire collapses because the murderer also spooks the markets as a double whammy, causing investors to panic and sell up. The relevant implications here is that despite her company not having changed its financial picture, it got cut up for scrap and thus lost most of its value, rendering the business worthless in the end. Companies are usually valued more as a going-concern, above what all its property put together would amount to. Where does that additional value come from? It’s the prospect of a return from this particular assemblage of resources.

Suffice it to say, the stock market is a lot of things. But I view it as a natural result of certain other prerequisites, meaning we can’t really get rid of it, so instead it should be appropriately regulated.

From an urban planning perspective, there are some caveats to your points:

A new downtown would make a subway very easy and cheap to build, you could cut and cover instead of tunnelling

Cut-and-cover will make shallow underground tunnels cheaper to construct in almost all cases irrespective of building in an old city center or as part of building a new city center from scratch. In fact, older pre-WW2 cities are almost ideal for cut-and-cover because the tunnels can follow the street grid, yielding a tunnel which will be near to already-built destinations, while minimizing costly curves.

Probably the worst scenario for cut-and-cover is when the surface street has unnecessary curves and detours (eg American suburban arterials). So either the tunnel follows the curve and becomes weirdly farther from major destinations, or it’s built in segments using cut-and-cover where possible and digging for the rest.

Cheeeaaap land for huge offices, roads, and even houses

At least in America, where agricultural land at the edges of metropolitan areas is still cheap, the last 70 years do not suggest huge roads, huge offices, and huge house lead to a utopia. Instead, we just get car-dependency and sprawl, as well as dead shopping malls. The benefits of this accrued to the prior generations, who wheeled-and-dealed in speculative suburban house flipping, and saddled cities with sprawling infrastructure that the existing tax base cannot afford.

Green field is just so cheap.

It is, until it isn’t. Greenfield development “would be short term appealing but still expensive when it comes to building everything”. It’s a rare case in America where post-WW2 greenfield housing or commercial developments pay sufficient tax to maintain the municipal services those developments require.

Look at any one municipal utility and it becomes apparent that the costs scale by length or area, but the revenue scales by businesses/households. The math doesn’t suggest we need Singapore-levels of density, but constant sprawling expansion will put American cities on the brink of bankruptcy. As it stands, regressive property tax policies result in dense neighborhoods subsidizing sprawling neighborhood, but with nothing in return except more traffic and wastewater.

Either these cities must be permitted to somehow break away from their failed and costly suburban experiments, or the costs must be internalized upon greenfield development, which might not make it cheap anymore.

A few months ago, my library gained a copy of Cybersecurity For Small Networks by Seth Enoka, published by No Starch Press in 2022. So I figured I’d have a look and see if it it included modern best-practices for networks.

It was alright, in that it’s a decent how-to guide for a novice to set up sensible, minimum network fortifications. But it only includes an overview of how those fortifications work, without going into the additional depth needed to fine-tune or optimize them for specific environments. So if the reader has zero experience with network security, it’s a worthwhile read. But if you’ve already been operating a network with defenses for a while, there’s not much to gain from this particular text.

Also, the author suggests that IPv6 should be disabled, which is a terrible idea. Modern best-practice is not to pretend IPv6 doesn’t exist, but to assure that firewalls and other defenses are configured to handle this traffic. There’s a vast difference between “administratively reject IPv6 traffic in/out of the WAN” and “disable IPv6 on all devices and pray no one ever connects an IPv6-enabled device”.

You might have a look at other books available from No Starch Press, though.

I lost it when coming across this commit: https://github.com/WinampDesktop/winamp/commit/67c68e6dc24f36b266427034d016fb86ef4d486c

The thing to keep in mind is that there exist things which have “circumstantial value”, meaning that the usefulness of something depends on the beholder’s circumstances at some point in time. Such an object can actually have multiple valuations, as compared to goods (which have a single, calculable market value) or sentimental objects (“priceless” to their owner).

To use an easy example, consider a sportsball ticket. Presenting it at the ballfield is redeemable for a seat to watch the game at the time and place written on the ticket. And it can be transferred – despite Ticketmaster’s best efforts – so someone else could enjoy the same. But if the ticket is unused and the game is over, then the ticket is now worthless. Or if the ticket holder doesn’t enjoy watching sportsball, their valuation of the ticket is near nil.

So to start, the coupon book is arguable “worth” $30, $0, or somewhere in between. Not everyone will use every coupon in the book. But if using just one coupon will result in a savings of at least $1, then perhaps the holder would see net-value from that deal. In no circumstance is KFC marking down $30 on their books because they issued coupons that somehow total to $30.

That said, I’m of the opinion that if a donation directly results in me receiving something in return… that’s not a donation. It’s a sale or transaction dressed in the clothes of charity. Plus, KFC sends coupons in the mail for free anyway.

Notwithstanding the possible typo in the title, I think the question is why USA employers would prefer to offer a pension over a 401k, or vice-versa.

For reference, a pension is also known as a defined benefit plan, since an individual has paid into the plan for the minimum amount will be entitled to some known amount of benefit, usually in the form of a fixed stipend for the remainder of their life, and sometimes also health insurance coverage. USA’s Social Security system is also sometimes called the public pension, because it does in-fact pay a stipend in old age and requires a certain amount of payments into the fund during one’s working years.

Whereas a 401k is uncreatively named after the tax code section which authorized its existence, initially being a deferred compensation mechanism – aka a way to spread one’s income over more time, to reduce the personal taxes owed in a given year – and then grew into the tax-advantaged defined contribution plan that it is today. That is, it is a vessel for saving money, encouraged by tax advantages and by employer contributions, if any.

The superficial view is that 401k plans overtook pensions because companies wouldn’t have to contribute much (or anything at all), shifting retirement costs entirely onto workers. But this is ahistorical since initial 401k plans offered extremely generous employer contribution rates, some approaching 15% matching. Of course, the reasoning then was that the tax savings for the company would exceed that, and so it was a way to increase compensation for top talent. In the 80s and 90s was when the 401k was only just taking hold as a fringe benefit, so you had to have a fairly cushy job to have access to a 401k plan.

Another popular viewpoint is that workers prefer 401k plans because it’s more easily inspectable than a massive pension fund, and history has shown how pension funds can be mismanaged into non-existence. This is somewhat true, if US States’ teacher pension funds are any indication, although Ontario Teacher’s Pension Plan would be the counterpoint. Also, the 401k plan participants at Enron would have something to complain about, as most of the workers funds were invested in the company itself, delivering a double whammy: no job, and no retirement fund.

So to answer the question directly, it is my opinion that the explosion of 401k plans and participants in such plans – to the point that some US states are enacting automatic 401k plans for workers whose employers don’t offer one – is due to 1) momentum, since more and more employers keep offering them, 2) but more importantly, because brokers and exchanges love managing them.

This is the crux: only employers can legally operate a 401k plan for their employees to participate in. But unless the employer is already a stock trading platform, they are usually ill-equiped to set up an integrated platform that allows workers to choose from a menu of investments which meet the guidelines from the US DOL, plus all other manner of regulatory requirements. Instead, even the largest employers will partner with a financial services company who has expertise on offering a 401k plan, such as Vanguard, Fidelity, Merrill Edge, etc.

Naturally, they’ll take a cut on every trade or somehow get compensated, but because of the volume of 401k investments – most people auto-invest every paycheck – even small percentages add up quickly. And so, just like the explosion of retail investment where ordinary people could try their hand at day-trading, it’s no surprise that brokerages would want to extend their hand to the high volume business of operating 401k plans.

Whereas, how would they make money off a pension fund? Pension funds are multi-billion dollar funds, so they can afford their own brokers to directly buy a whole company in one-shot, with no repeat business.

Although copyright and patents (and trademarks) are lumped together as “intellectual property”, there’s almost nothing which is broadly applicable to them all, and they might as well be considered separately. The only things I can think of – and I’m not a lawyer of any kind – are that: 1) IP protection is mentioned vaguely in the US Constitution, and 2) they all behave as property, in that they can be traded/reassigned. That’s it.

With that out of the way, it’s important to keep in mind that patent rights are probably the strongest in the family of IP, since there’s no equivalent “fair use” (US) or “fair dealing” (UK) allowance that copyright has. A patent is almost like owning an idea, whereas copyright is akin to owning a certain rendition plus a derivative right.

Disney has leaned on copyright to carve for themselves an exclusive market of Disney characters, while also occasionally renewing their older characters (aka derivatives), so that’s why they lobby for longer copyright terms.

Whereas there isn’t really a singular behemoth company whose bread-and-butter business is to churn out patents. Inventing stuff is hard, and so the lack of such a major player means a lack of lobbying to extend patent terms.

To be clear, there are companies who rely almost entirely on patent law for their existence, just like Disney relies on copyright law. But type foundries (companies that make fonts) are just plainly different than Disney. Typefaces (aka fonts) as a design can be granted patents, and then the font files can be granted copyright. But this is a special case, I think.

The point is: no one’s really clamoring for longer parents, and most people would regard a longer exclusive term on “ideas” to be very problematic. Esp if it meant pharmaceutical companies could engage in even more price-gouging, for example.

If you hold a patent, then you have an exclusive right to that invention for a fixed period, which would be 20 years from the filing date in the USA. That would mean Ford could not claim the same or a derivative invention, at least not for the parts which overlap with your patent. So yes, you could sit on your patent and do nothing until it expires, with some caveats.

But as a practical matter, the necessary background research, the application itself, and the defense of a patent just to sit on it would be very expensive, with no apparent revenue stream to pay for it. I haven’t looked up what sort of patent Ford obtained (or maybe they’ve merely started the application) but patents are very long and technical, requiring whole teams of lawyers to draft properly.

For their patent to be valid, they must not overlap with an existing claim, as well as being novel and non-obvious, among other requirements. They would only file a patent to: 1) protect themselves from competition in future, 2) expect that this patent can be monetized by directly implementing it, or licensing it out to others, or becoming a patent troll and extracting nuisance-value settlements, or 3) because they’re already so deep in the Intellectual Property land-grab that they must continue to participate by obtaining outlandish patents. The latter is a form of “publish or perish” and allows them to appear like they’re on the cutting edge of innovation.

A patent can become invalidated if it is not sufficiently defended. This means that if no one even attempts to infringe, then your patent would be fine. But if someone does, then you must file suit or negotiate a license with them, or else they can challenge the validity of your patent. If they win, you’ll lose your exclusive rights and they can implement the invention after all. This is not cheap, and Ford has deep pockets.

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.