portent (u/portent) - Readit News

portent commented on Bitcoin's fungibility graveyard sethforprivacy.com/posts/... · Posted by u/rzk

mw888 · 4 years ago

Legally identical is a nonsense metric: if I own bitcoin I cannot sell because it has a tainted history then it is obviously not equivalent and not as valuable as bitcoin which can be.

The fact that no broker cares about which instance of the stock or dollar you own but can track it anyways proves that those things are effectively fungible. In Bitcoin it is obviously not true that exchanges don’t care in the same way - plainly obvious from the source material you are responding to.

When different bitcoin have different value by virtue of not being exchangeable at the largest liquidity pools, and your definition of fungible fails to capture that fact, you have the wrong definition.

portent · 4 years ago

The same can be true of dollar bills. A bag full of dollar bills from a drug deal is fungible with a bag full of dollars from your salary. But you can be arrested for the former, and not the latter. Dollars are fungible with dollars ($1+$1=2$), NFTs are not fungible with NFTs (1NFT+1NFT=1NFT+1NFT).

portent commented on Insurance is like gambling, don't overdo it blog.viktomas.com/posts/i... · Posted by u/vicek22

lordnacho · 4 years ago

You're absolutely right, the thing to look at here is the St Petersburg problem.

You have a coin, and each time you don't get heads the payout doubles. Get heads and get the payout. What do you pay to play this?

It turns out that you can't work out an E[X] for this, as it's a series that doesn't converge. But also if you go around and ask people what they'd pay, surprisingly they don't say infinity. Expectation is thus not the last word in decision making.

Turns out utility is a thing that matters, and we can come up with some thoughts on it (von Neumann-Morgenstern etc).

portent · 4 years ago

re: surprisingly they don't say infinity

I'm not sure it's that surprising, the expectation is only infinity if you think the person making the payout has the capacity to pay an infinite amount. The second you think this amount is finite (which must always be the case in reality), then the expectation becomes finite and probably quite small.

I agree in the more general point, expectation is not always the best tool for extremely rare / extremely significant scenarios.

portent commented on R number for UK below 1 for first time since August bbc.co.uk/news/health-551... · Posted by u/jlokier

rwmj · 5 years ago

All the students are going to be sent home soon to visit their old folks at Christmas, what could possibly go wrong?

portent · 5 years ago

I think the UK government realised its mistake, and is trying to unwind it as safely as possible.

"From 3 December to 9 December, which will be known as the ‘student travel window’, students will be allowed to travel home on staggered departure dates set by universities, who will work with other institutions in the region to manage pressure on transport infrastructure.

The student travel window will mean students can travel having just completed the four-week period of national restrictions, reducing the risk of transmission to family and friends at home.

Universities should move learning online by 9 December so students can continue their education while also having the option to return home to study from there."

https://www.gov.uk/government/news/christmasguidance-set-out...

portent commented on A list of lists of interview questions github.com/MaximAbramchuc... · Posted by u/melenaos

paulie_a · 7 years ago

The poster literally said they were going to intentionally say things that they know are false.

That's pretty much the definition of a liar and outright deceptive.

Besides that, the tactic of trying to be debative and in this case outright dishonest and slightly combative is an incredibly terrible method for interviews.

Honestly the poster should be banned from giving interviews.

portent · 7 years ago

The poster is using an interview technique of creating an imaginary scenario, e.g. "deal with a work colleague who is advocating a sub-optimal position". This seems entirely reasonable.

It seems to me that you've jumped to a very strong conclusion, based on a brief conversation that you have interpreted in the least charitable way possible.

portent commented on Ask HN: Have you ever regretted working on a product? · Posted by u/mavsman

BurnGpuBurn · 7 years ago

> The existence of liquid markets is beneficial for the producers and consumers as the price volatility is reduced and hedging becomes easier.

Yeah, that's a nice fairy tale. It isn't true though. It's criminally untrue.

I can't eat volatile grain, nor hedged grain. I just eat grain. At a price I can afford, today and tomorrow, not bankrupting me in the process. When you're hungry you really don't care about all the financial jargon. You care about price.

Traders cannot make a profit if they don't manipulate the price. Simple, if a trader always sold for the same price he bought for he wouldn't make any money. So price goes up, trader has profited from the grain I eat, and has taken a few cents out of my pocket. And I don't even trade. I just live on a dollar day in a shithole somewhere.

If everybody bought just the grain they needed to eat, and every grain producer simply put their product on the market for people to buy, without a "liquid global market" and price index, without traders in the middle wanting to profit from it, my food would be affordable. But because the market bets on a price rise in the future, even though the bad weather hasn't materialized yet, my food is unaffordable.

In financial, when someone profits, someone hurts. And the one that hurts is almost always not even in the game.

> Significantly influencing the price of a commodity [...] is pretty much impossible unless you're acting on behalf of a country or are able to control weather.

No. A market can do that by itself. It's what all those terms bullish and bearish and stuff are for. Markets can drive up commodity prices like a rocket. Bad weather coming? "Let's buy all the grain everybody! Guaranteed profit! Just ignore the starving people over there, they'll go away fast enough." And buy the way, all those think tanks and the pentagon predicting a shortage of every natural resource in the near future, that's not going to influence the price at all, right? Great example of how a country manipulates commodity prices btw.

Financial trade is just people profiting from people who are worse off to begin with. And don't start about how nowadays regulations are much tighter and all that, it's just not true. Everybody always says that in times when stuff is stable, but as soon as something big happens everybody starts the "nobody could have forseen this" dance followed by the too-big-to-fail entities being saved by the govt and the bill footed to the people.

portent · 7 years ago

Traders typically provide two prices - the price they will buy at and the price they will sell at. Their profit comes from the spread between. A good trader does not care if the market moves up or down, they make their money on the spread, a trader typically wants as little inventory as possible.

The people who cause markets to move are not the traders, they are the people who buy from and sell to the traders.

portent commented on Ask HN: Have you ever regretted working on a product? · Posted by u/mavsman

apexalpha · 7 years ago

I don't know I think it'd be pretty interesting to find out that Wall Street is not actually part of NYC but has it's own police, government etc... purely for benefit of the banks.

portent · 7 years ago

You might then be interested to know that the Federal Reserve bank has its own dedicated police force/

https://en.m.wikipedia.org/wiki/Federal_Reserve_Police

portent commented on Unroll.me to close to EU users saying it can’t comply with GDPR techcrunch.com/2018/05/05... · Posted by u/prostoalex

downandout · 7 years ago

If they intended for there to be safeguards, those would have been built in. They. Are. Not. There.

portent · 7 years ago

I'm sure technically you are right on the written wording of the law, but you can be technically right on many subjects and make the wrong business calls. Avoiding a vanishingly small regulatory risk by making real damage to your company seems like a bad call.

You could totally eliminate the risk of meteorite impact on your business by relocating down a mineshaft...

portent commented on Unroll.me to close to EU users saying it can’t comply with GDPR techcrunch.com/2018/05/05... · Posted by u/prostoalex

kelnos · 7 years ago

> The more difficult part is deletion from backups, which is also a requirement.

How long do you keep your backups? If you just store them for, say, 30 days, that's fine. The EU regulators aren't going to come after you for a 30-day lag for all traces of data to be deleted, as long as that process is documented.

There's still one annoyance left: you do need to keep track of accounts/users who have deleted data, so if you have to restore from a backup, you can't restore any data belonging to users who have deleted their data within that window.

Otherwise, this is frankly not such a big deal. If you're storing backups for longer than 30 days, why? Where I work, if we had to restore from a 30-day-old backup, it'd be catastrophic for the business given how much data would be lost.

portent · 7 years ago

Many regulated industries need to store data for multiple years, often in a secure format e.g. WORM storage

portent commented on Never Write Your Own Database (2017) medium.com/@terrycrowley/... · Posted by u/ahiknsr

SQLite · 7 years ago

You are no doubt correct about points (2) and (5). But just to set the record straight, points (1), (3), and (4) are mistaken.

The standard build of SQLite uses an OS, but there is a compile-time option to omit the OS dependency. It then falls to the developer to implement about a dozen methods on an object that will read/write from whatever storage system is used by the device. People do this. We know it works. We once had a customer use SQLite as the filesystem on their tiny little machine.

Likewise, the use of malloc() is enabled by default but can be disabled at compile-time. Without malloc(), your application has to provide SQLite a chunk of memory to use at startup. But that is all the memory that SQLite will ever use, guaranteed. Internally, SQLite subdivides and allocates the big chunk of memory, but we have mathematical proof that this can be done without ever encountering a memory allocation error. (Details are too long for this reply, but are covered in the SQLite documentation.)

Finally, we do have proof that SQLite can continue after a power cycle - assuming certain semantics provided by the storage layer. Hence, the proof depends on your underlying hardware and those methods you write to access the hardware for (1) above. But assuming those all behave as advertised, SQLite is proof against data loss following an unexpected power cut. We have demonstrated this by both code analysis, and experimentally.

So probably you were correct to write your own database in this case. My point is that SQLite did not miss your requirements by quite as big a margin as you suppose. If you had had a bigger hardware budget (SQLite needs about 0.5MB of code space and a similar amount of RAM, though the more RAM you feed it the faster it runs) then you might have been able to save yourself about two years of development effort.

portent · 7 years ago

That's a great and informative answer, only minor comment that I think OP said the project was 2 years but the database portion was 1 month of that 2 years.

Still I agree better not to roll your own stuff unless it is absolutely critical.

portent commented on Dropbox saved almost $75M over two years by moving out of AWS geekwire.com/2018/dropbox... · Posted by u/shaklee3

dzdt · 8 years ago

AWS sells optionality. If you build your own data center, you are vulnerable to uncertain needs in a lot of ways.

(1) your business scales at a different rate than you planned -- either faster or slower are problems!

(2) you have traffic spikes, so you to over-provision. There is then a tradeoff doing it yourself: do you pay for infrastructure you barely ever use, or do you have reliability problems at peak traffic?

(3) your business plans shift or pivot

A big chunk of the Amazon price should be considered as providing flexibility in the future. It isn't fair to compare prices backwards-looking: where you know what were your actual needs and can compare what it would have cost to meet those by AWS vs in house.

The valid comparison is forward looking: what will it cost to meet needs over an uncertain variety of scenarios by AWS compared to in-house.

The corallary of this is, for a well-established business with predictable needs, going in-house will probably be cheaper. But for a growing or changing or inherently unpredictable business, the flexibility AWS sells makes more sense!

portent · 8 years ago

A good option can be to use your own data center for base load, and on top of that use AWS for traffic spikes. That way you still have the flexibility to adapt quickly but at a lower cost, once you reach a certain scale.