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zgs

135 karma · joined May 29, 2020

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zgs··on Memory safety absolutists
I don't the fanaticism around memory safe languages. We've had memory safe languages for a very long time. Algol-60, the granddaddy of many modern languages, had it sixty-five years ago. Algol-60 also had other safety features that modern languages don't have - for example integer overflow safety.

The real issue is that we came to accept unsafe languages and are taking a really long time to put such features back.

zgs··on RSA Munitions T-Shirt
I've still got mine. It's been well used but is hanging together still.
zgs··on The Arc spacecraft: designed to deliver cargo anywhere in an hour
Seems like another way to deliver nukes to targets...
zgs··on The future of 32-bit support in the kernel
Under uClinux, executables can be position independent or not. They can run from flash or RAM. They can be compressed (if they run in RAM). Shared libraries are supported on some platforms. All in all it's a really good environment and the vfork() limitation generally isn't too bad.

I spent close to ten years working closely with uClinux (a long time ago). I implemented the shared library support for the m68k. Last I looked, gcc still included my additions for this. This allowed execute in place for both executables and shared libraries -- a real space saver. Another guy on the team managed to squeeze the Linux kernel, a reasonable user space and a full IP/SEC implementation into a unit with 1Mb of flash and 4Mb of RAM which was pretty amazing at the time (we didn't think it was even possible). Better still, from power on to login prompt was well under two seconds.

zgs··on The future of 32-bit support in the kernel
Out by a factor of five or more.

A $1 Linux capable ARM: https://www.eevblog.com/forum/microcontrollers/the-$1-linux-...

I'd expect that there were even cheaper processors now since it's eight years later.

zgs··on Decimal FP faster than binary?
I used decNumber in the WP 34S project (https://sourceforge.net/projects/wp34s/) and more recently in the C47 project (https://47calc.com).

You are correct in that the decNumber library doesn't support trig operations. Arithmetic, log, exp and square root plus rounding and some conversion functions.

My experience is that decNumber is generally slow. Logarithms are especially slow. Intel's decimal library is much faster & as you noted, it uses binary operations to start it's algorithms.

zgs··on Show HN: AI challenge – generate ECX = 0x08C0C166 with no memory, no immediates
It might be shorter to do some multiplications:

0x08C0C166 = 2⁴ × 3 × 5⁵ × 11 × 89 + 1 = 10⁴ × 3 × 5 × 11 × 89 + 1

Plenty of values that can be reused (11 = 10 + 1 and 89 = 10² - 11).

Still, there is quite a bit of manipulation required and only 17 instructions to do them in.

zgs··on Show HN: AI challenge – generate ECX = 0x08C0C166 with no memory, no immediates
The initial XOR instruction isn't required, registers are zeroed as per the problem statement.
zgs··on Trump says he will check amount of gold stored at Fort Knox
Better check his pockets on the way out :)
zgs··on Elon and His Bananas
I think there is a spurious "and H" in the title :)
zgs··on How the Atari ST Almost Had Real Unix
Later uClinux was available on m68k platforms without memory managers. The approach taken doesn't seem close to the one in the article.

I managed to put in shared execute in place library support, the limitation being the number of shared libraries rather than what they supported.

zgs··on Optimality of Gerver's Sofa
My favourite mathematical problem looks to have been solved.
zgs··on The Code That Almost Led to Disaster • a Starbase Story
There is a second issue with the code. The calculation of the mean isn't numerically stable. Instead use:

mean_power = mean_power + (power - mean_power) / count

zgs··on Algol-68 seemed like a good idea
Algol 68 was to Algol as C++ is to C: trying to do too much resulting in over-complexity.

The two page spread showing a graph of the implicit type conversions was a masterpiece.

zgs··on Bug squash: An underrated interview question
Kind of like the "install this software" as part of the interview process.

"My hourly rating for figuring out your bug is $X".

zgs··on Faster random integer generation with batching
A division free integer in a range RNG has been developed: https://github.com/apple/swift/pull/39143
zgs··on Could we put data centers in space?
What a crazy idea.

Cost to orbit is huge. Power availability will depend on pushing enough solar up there. Data centres use lots of power.

Getting rid of excess heat is a major problem in space and data centres generate lots of it. Terrestrial cooling is trivial in comparison.

Hardware obsolesce will be a major hurdle as will repairing stuff that fails.

Radiation is a significant problem in space. Shielding will be very heavy or the hardware will have to be build tolerant which is much more expensive and results in a much slower solution.

Much easier and cheaper to install lots of solar and batteries in the middle of a sunny desert somewhere really cheap and build your data centre there. Then build fibre connections to wherever.

zgs··on Ointers: A library for representing pointers where bits have been stolen (2021)
Every time I've seen similar done in the past, it has come back to hurt the instigator.
zgs··on [dead]
We're all upside down here and the blood rushes to our heads.

While living in the antipodes gives most of us genius level intelligence, it also prevents interpersonal relationships.

It's a trade off unfortunately.

If you live down under and want more friends, you need to do head stands for long periods to reduce the over oxygenated brain symptoms.

zgs··on Ask HN: Cryptography technique to hide monotonically increasing GUIDs
This is the easiest way to go but it's only obscuring the GUID. Format preserving encryption (FPE) would be another possibility if it's not simply a byte string.
zgs··on California Must Triple Rate of Carbon Emissions Reductions to Reach 2030 Target
Is California one of the more progressive states with regards to reductions?

This does not bode well for the world we share.

zgs··on Is it too late to enter software engineering in 2024?
As a career programmer, I'm not in the least concerned that LLMs will replace me. At least not in the near to mid term future. The key is to have skills that LLMs aren't good at replicating. Writing secure code, numerically stable code, performance optimised code, resource tight code....
zgs··on How do computers calculate sine?
It would also be extremely inaccurate. The x^n numerators grow very quickly and digits get lost because unlimited precision isn't available. Likewise, the n! denominators also grow rapidly. Then the series is alternating which means cancellation is happening for every added term.

If you don't believe me try for x=10.

zgs··on [dead]
18 Indians have signed up with Russia.

More US citizens have been killed already: https://taskandpurpose.com/news/americans-killed-ukraine-rus....

This isn't a news story, it's propaganda.

zgs··on Every default macOS wallpaper
I was far more used to the MacsBug screen of despair.
zgs··on Maybe Everything Is a Coroutine
The programming language Beta took this way further many years ago:

https://beta.cs.au.dk

It's syntax didn't help it's spread unfortunately.

zgs··on Twenty years of my work with Arm architecture
I wrote the boot loader for HP's StrongARM 1110 based calculator line.

Sadly the ACO was shut down before it's release.

Even though it was never released to the public a few escaped the labs and I've still got the dev kits they sent for boot loader work.

zgs··on White House wants to 'cryptographically verify' videos of Joe Biden
The only possibility is to cryptographically sign all videos using a White House private key.

Using a digest or MAC is not sufficient: it has to be asymmetric (i.e. public/private key).

zgs··on Ask HN: Good Books on Time Series Analysis?
Yes :)

Oh you want a reference. Sadly, I don't remember the text book we used three or so decades back. It was good. The title was simply: "Time Series Analysis".

This is kind of a counterexample for Betteridge's law.

zgs··on New Project Idea
A life?
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