oshiar53-0 · HackerTrans

oshiar53-0

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An entire website showing how to obtain backtrace on Windows

stackwalk.com

1 pointsby oshiar53-0قبل 5 سنوات0 comments

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قبل 4 سنواتdiscuss

Does this mean that 0 Hz bandwidth leads to the ideal clock?

قبل 4 سنواتdiscuss

Fun fact: GB 18030 is a Unicode Transformation Format.

Example: \N{THINKING FACE}\N{FACE WITH TEARS OF JOY}\N{FACE SCREAMING IN FEAR}\N{SMILING FACE WITH SMILING EYES AND THREE HEARTS}\N{PERSON DOING CARTWHEEL}\N{FACE WITH NO GOOD GESTURE}\N{ZERO WIDTH JOINER}\N{FEMALE SIGN}\N{VARIATION SELECTOR-16}\N{EYES}\N{ON WITH EXCLAMATION MARK WITH LEFT RIGHT ARROW ABOVE}\N{SQUARED COOL}\N{VARIATION SELECTOR-16}

In UTF-8:

  00000000: f09f a494 f09f 9882 f09f 98b1 f09f a5b0  ................
  00000010: f09f a4b8 f09f 9985 e280 8de2 9980 efb8  ................
  00000020: 8ff0 9f91 80f0 9f94 9bf0 9f86 92ef b88f  ................

In GB 18030:

  00000000: 9530 cd34 9439 fc38 9530 8335 9530 d636  .0.4.9.8.0.5.0.6
  00000010: 9530 d130 9530 8535 8136 a439 a1e2 8431  .0.0.0.5.6.9...1
  00000020: 8235 9439 cf38 9439 e537 9439 8b32 8431  .5.9.8.9.7.9.2.1
  00000030: 8235                                     .5

قبل 4 سنواتdiscuss

I assume this uses thunks not unlike some lazily-evaluated languages?

قبل 4 سنواتdiscuss

Doesn't this mean that non-blocking reads from /dev/urandom can now potentially return -EAGAIN (at e.g. very early boot time)? I think that's enough to subtly (nondeterministically) break userspace, in the short time window the entropy pool is not seeded enough, even if (C) and (D) do not hold.

قبل 4 سنواتdiscuss

To be fair, it has computed the page at least once at some point...

قبل 4 سنواتdiscuss

a truely randall number

قبل 4 سنواتdiscuss

https://man7.org/linux/man-pages/man2/membarrier.2.html provides a good example of when a processor memory barrier is eliminated but a compiler memory barrier is still required.

قبل 4 سنواتdiscuss

Are you mad? I didn't even criticize Unix at all!

قبل 4 سنواتdiscuss

> I think that an operating system where you can't rename or delete a file that is open by some process is idiotic beyond words,

This is not an inherent limitation of the VMS or NT architecture; I'd rather argue it's for compatibility.

> even without MS-DOS drive letter names thrown in.

This is also legacy carried over from DOS and OS/2.

قبل 4 سنواتdiscuss

How about static inline functions?

قبل 5 سنواتdiscuss

This is the insight I wanted.

Now I want to hear what FSF has to say about this...

قبل 5 سنواتdiscuss

> it's almost mandated by law that there can't be. FCC regulations require that devices be made resistant to attempts to change their function in an effort to limit people's ability to transmit stuff unintentionally (or intentionally). Modern radio protocols are heavily dependent on SDR (software defined radio), so fixed function is probably infeasible. You could make the firmware unchangeable, but now any bugs discovered in your public source code are now entirely uncorrectable.

1. You can use signed firmwares to make it both compliant and upgradable.

2. You can separate the controller/receiver and the transmitter, and only lock up/restrict the transmitter part. Alternatively, you can implement the restriction at the hardware level if feasible (effectively making it fixed function).

3. Finally, you can sell the parts individually to serve a separate market segment.

قبل 5 سنواتdiscuss

>"They should die for the cause."

In his stance, more like "proprietary driver vendors are holding hostage of patients."

قبل 5 سنواتdiscuss

See https://www.fsf.org/campaigns/free-bios.html for the rationale.

Basically, FSF had to make a compromise here. If you use Flash ROM (or other writable medium), the firmware counts as a nonfree software. However, if you use actual ROM, the firmware might as well have been a circuit baked right in the product, so it counts as hardware; nevertheless, it counts as non-free.

FSF's ultimate goal would of course be to be able to certify that every component (hard or soft) of the system is actually free. However, this isn't very practical, since no consumer-grade computers will be considered free due to proprietary CPUs (e.g. Intel, AMD, ARM), which is why FSF is stuck in a weird situation. (How would you make exceptions for the CPU stock microcode and not the BIOS, for example?)

For that matter, I hope RISC-V helps us go a step forward...

قبل 5 سنواتdiscuss

Make sure you don't roll your own crypto on your way, though.

Unless when it somehow becomes the absolute necessity...or it's for your dissertation.

قبل 5 سنواتdiscuss

Talk about lockdowns...

قبل 5 سنواتdiscuss

It's worth noting that Fedora/RHEL's postinstall is generally less intrusive than Debain's, though.

For instance it doesn't just automatically create databases or starts/enables services.

قبل 5 سنواتdiscuss

Clearly you haven't heard of HasThisTypePatternTriedToSneakInSomeGenericOrParameterizedTypePatternMatchingStuffAnywhereVisitor

http://dev.eclipse.org/viewcvs/index.cgi/org.aspectj/modules...

قبل 5 سنواتdiscuss

(Commenting here since the other thread is going nowhere)

To clarify, the main property of a non-blocking algorithm is that it's exclusively composed of simpler, smaller ("atomic") operations that demonstrate time-bound/progress-making guarantees, in turn making the bigger algorithm generally easier to reason about (Note "generally").

The consequence of this argument is twofold:

1. It's entirely possible to make a blocking algorithm provide the same guarantees as a non-blocking algorithm, as long as the underlying operations (blocking or otherwise) are proven to be correct. Blocking algorithm tend to throw other complex systems into the mix (e.g. the scheduler), and all of the dependencies and their usages have to be correct (w.r.t. whatever property we desire) to show that the final blocking algorithm is also correct. For instance, it can be argued that the priority inversion problem stems from the lack of scheduler's correctness, or alternatively, the incorrect use of the scheduler. However, in the absense of such problems, there are effectively no disadvantages on blocking algorithms on this respect.

2. If it turns out any atomic operations below the non-blocking algorithm do not meet the expected guarantees, then the non-blocking algorithm itself also becomes unsafe. I think the OP clearly demonstrates this problem--the CPU atomic instructions are but some kind of hardware "locks" (either a LOCK# pin on older processors or some complex cache coherency protocol, but this is an implementation detail) on their own that can sometimes fail to meet the programmer's expectations, leading to surprising results.

In short, the fine line between blocking algorithms and nonblocking algorithms can be drawn by whichever smaller operations or components we assume to be correct.

قبل 5 سنواتdiscuss

OpenBSD does something similar but in a reverse manner. It's called Kernel Address Randomized Link (KALR).

What it does is bundling kernel object files into an archive, which is linked at boot time to form the final kernel image. Note that the link order is randomized each time the kernel boots, since KALR is a security vulnerability mitigation designed to thwart exploitation attempts.