because of OS-level overcommit, which is nearly always a good thing
It doesn't matter about the language you are writing in, because your OS can tell you that the allocation succeeded, but when you come to use it, only then do you find out that the memory isn't there.
Of course it matters, because you (the system admin) can tell your OS not to do that. Which is only helpful if your app knows how to handle the case. Most don't, so overcommit, in general, makes sense.
> You can't really on linux. There's no way to do sparse allocations then because when you turn off overcommit MAP_NORESERVE still reserves memory...
Sure, but ... what does that have to do with this thread? Using `mmap` is not the same as using `malloc` and friends.
If you turn off overcommit, malloc will return NULL on failure to allocate. If you specifically request mmap to ignore overcommit, and it does, why are you surprised?
> If you specifically request mmap to ignore overcommit, and it does, why are you surprised?
You misunderstand, you specifically request mmap to ignore overcommit, and it doesn't, not does.
What it has to do with this thread is it makes turning off overcommit on linux an exceptionally unpalatable option because it makes a lot of correct software incorrect in an unfixable manner.
Oxbridge have never had to 'let in dumber people'. They are always heavily over-subscribed, and give offers to a small fraction of the people who come for an interview, let alone apply.
The whole point of the interview process is to assess not just the applicant's past achievements, but what they might be able to achieve if they got their place at the uni. Part of that is looking at the applicant's background, and knowing that even if they aren't currently at some elite high-fee school, they might still have the ability and capability to do well.
I am all in favor of this style of selection. The dark old days of "this kid's dad went to our college, we should do them a favour and let them in" are long gone, thankfully.
Can you point to any kind of evidence that Oxbridge are dumbing down their teaching, or lowering their standards of teaching? I doubt it.
Full disclosure: cambridge alumni, from a state school!
In addition, the colleges have a lot of data about the people they interview and how well they do during the degree programme.
My understanding (based on a discussion with one Natural Sciences admissions tutor at one Cambridge college nearly 20 years ago, so strictly speaking this may not be true in general, but I'd be surprised if it wasn't common) is that during the admissions process, including interviews, applicants are scored so they can be stack-ranked, and the top N given offers. Then, for the students that are accepted, and get the required exam results, the college also records their marks at each stage of their degree. To verify the admissions process is fair, these marks are compared with the original interview ranking, expecting that interview performance is (on average) correlated with later degree performance.
I don't know if they go further and build models to suggest the correct offer to give different students based on interview performance, educational background, and other factors, but it seems at least plausible that one could try that kind of thing, and have the data to prove that it was working.
Anyway my guess is that of the population of people who would do well if they got in, but don't, the majority are those whose background makes them believe it's "not for the likes of me", and so never apply, rather than people who went to private schools, applied, and didn't get a place.
(also a Cambridge alumni from a state school, FWIW),
All these Cambridge alumni with this dodgy Latin, 'smh'! You're an alumnus, or identifying as an alumna! (Identifying as many alumni at a stretch, but then still not 'a Cambridge alumni'.)
(alumnus not of Cambridge, but from a state school, fwiw)
On student evaluations, I wouldn't be surprised of Oxbridge do badly as so many pf the dons were at or near the top of their year at the university, weren't employed for their teaching abilities, and seemed unable to comprehend they were not teaching cohorts entirely full of clones of themselves.
Dumbed down it was not, in my experience. Dumbing down would be a way to up the score on these rankings, though.
And is this new generation doing paticularly well in solving our problems or advancing the nation over the previous one? I can't see much examples, I do remember going through some of the science projects shown in undergrad showcase but none of them were tackling key bottlenecks or doing something novel.
Improvement suggestion: Keep the search text in the search field when you show the results. The 'what are you looking for' box gets cleared when you show the results, it would be nicer if the search text was kept so that you could tweak it.
Thanks for the feedback. We're still working out the ideal way to manage the search, lots of trade-offs depending on what route you go. But there's definitely room for improvement.
Does that mean it excludes most of the results from "Floor to ceiling libraries without a ladder"?
You know, if I'm buying a house, I think I can supply my own ladder separately...
Less pedantically, what I'm trying to say is: are you really sure these are the kinds of searches that home buyers are really looking for? "Home in london, under £1m, with big beautiful windows" - I suspect that most London buyers are going to care an awful lot about where in London the house is, a city-wide search isn't going to be useful to most. Maybe your functionality (as presented) won't inspire actual buyers.
Speaking of which, that might be a way to improve it - combine with location & mapping data to figure out nearby transport, services, schools, etc...
For sure, those searches are more about showing what’s possible (and making browsing fun) than what a high-intent buyer would actually type in.
That said, from speaking to a lot of London buyers, people are often more flexible on location than you’d expect. The real criteria tend to look more like: “3-bed house under £700k, 30 min commute from [office], near a park, low crime, good schools” rather than “3-bed in Hackney.” Basically along the lines of the location / mapping data you're suggesting.
We’ve already built travel-time search and plan to layer in more of that other 'services' style data in the next few months.
But it is (or was originally) used in lots of places, not just jump tables, generally to do relative addressing, for example when you want to refer to data nearby, e.g.
Ah I miscommunicated, I still think PC can and should be used in places like the operand of an LDR / ADD. It's using it as the output of certain instructions (and allowing it to be used as such) that I take issue with. ARMv4T allowed you to set PC as the output of basically any instruction, allowing you to create cursed instructions like this lol:
Isn't writing to it except by a branch instruction undefined behaviour?
If you can use it as an operand, it has a register number, so you can use it as a result, unless you special-case one or the other, which ARM didn't do because it was supposed to be simple. They could have ignored it by omitting some write decode circuitry, but why?
It's not really UB, I've seen games do things like this before. Basically, all data processing instructions can now act as branch instructions, simply by having their dest be PC. Bowser's Inside Story on the DS for example liked to use EOR to write to PC, as a form of encrypting their pointers.
Yeah I think AARCH64 special cases it? Not too familiar with their encoding or how they achieved it. My guess as to why is that it allows you to use more helpful registers (e.g. a zero register) in data processing instructions.
I think I can see your point though - from the perspective of ARMv4T's design, which was to be a simple yet effective CPU, making the PC a GPR does its job. Nowadays the standards are different, but I can see why it made sense at the time.
Works on contingency
No money down
Always the best example for missing punctuation!
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