Programming Leftovers
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Rlang ☛ Adaptive Asset Allocation Replication
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Rlang ☛ Exploring TidyAML: Simplifying Regression Analysis in R
If you’re a data enthusiast diving into the world of regression analysis in R, you’ve likely encountered the challenges of managing code complexity and juggling different modeling engines.
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Qt ☛ Future text improvements in Qt 6.7
The Qt 6.7 feature freeze is today, and we now start the process of further stabilizing the code. The actual release is still a few months off, but I thought I would look ahead at bit at what improvements are in store for font handling in Qt and Qt Quick. More specifically there are three things discussed: Variable font support, a brand new "large font" text renderer and font shaping feature support.
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Qt ☛ "Coding in the Dark" or what one can do in Qt in 10 minutes
AWell, not only in just 10 minutes, but with other hard limitations on top! Qt developers have shown that a small but functional app can still be made! Let's have a look at how it went and what we learned.
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Andy Wingo: v8's mark-sweep nursery
Today, a followup to yesterday’s note with some more details on V8’s new young-generation implementation, minor mark-sweep or MinorMS.
A caveat again: these observations are just from reading the code; I haven’t run these past the MinorMS authors yet, so any of these details might be misunderstandings.
The MinorMS nursery consists of pages, each of which is 256 kB, unless huge-page mode is on, in which case they are 2 MB. The total default size of the nursery is 72 MB by default, or 144 MB if pointer compression is off.
There can be multiple threads allocating into the nursery, but let’s focus on the main allocator, which is used on the main thread. Nursery allocation is bump-pointer, whether in a MinorMS page or scavenger semi-space. Bump-pointer regions are called linear allocation buffers, and often abbreviated as Lab in the source, though the class is LinearAllocationArea.
If the current bump-pointer region is too small for the current allocation, the nursery implementation finds another one, or triggers a collection. For the MinorMS nursery, each page collects the set of allocatable spans in a free list; if the free-list is non-empty, it pops off one entry as the current and tries again.
Otherwise, MinorMS needs another page, and specifically a swept page: a page which has been visited since the last GC, and whose spans of unused memory have been collected into a free-list. There is a concurrent sweeping task which should usually run ahead of the mutator, but if there is no swept page available, the allocator might need to sweep some.
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Open Hardware/Modding
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Hackaday ☛ When Is A 6502 Not Quite A 6502?
We all know that fake chips are a risk when it comes to buying parts on eBay or from Chinese markets such as AliExpress. It’s a simple enough scam, take a cheap chip and mark it as an expensive one, pocket the difference. It’s happened in several different forms, with everything from completely different devices through cheaper equivalents to incredibly, chips purpose fabricated to emulate better-known ones. We have a chance to see such a scam in action via [LinuxJedi], with a 6502 that wasn’t quite as it seemed.
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Linux Gizmos ☛ Plug-and-play network camera starts at $14.90
Today, M5Stack unveiled a compact, pocket-sized camera unit, integrating the ESP32-S3 module and the OV2640 image sensor. This 2MP resolution camera offers a broad 66.5° diagonal field of view. Designed for versatility, it is ideally suited for tasks such as time-lapse photography and various computer vision applications that require wireless connectivity.
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