Want to learn the internals of the Linux kernel? Version 6.5-rc5 has about 36 million lines of code in it, so good luck! [Seiya] has a different approach. Go back to the beginning and examine the 0.01 version of the kernel. Now you are talking about 10,000 lines and, removing comments and blanks, way less.
Sure, some things have changed, but the core ideas are the same. [Seiya] reports, “Reading V0.01 was really for me. It was like visiting Computer History Museum in Mountainview…”
Modern microcontrollers like the RP2040 and ESP32 are truly a marvels of engineering. For literal pocket change you can get a chip that’s got a multi-core processor running at hundreds of megahertz, plenty of RAM, and more often than not, some form of wireless connectivity. Their capabilities have been nothing short of revolutionary for the DIY crowd — on any given day, you can see projects on these pages which simply wouldn’t have been possible back when the 8-bit Arduino was all most folks had access to.
Thanks to the increased performance of these MCUs, hackers and makers now even have a choice as to which programming language they want to use. While C is still the language of choice for processor-intensive tasks, for many applications, Python is now a viable option on a wide range of hardware.
This provides a far less intimidating experience for newcomers, not just because the language is more forgiving, but because it does away with the traditional compile-flash-pray workflow. Of course, that doesn’t mean the more experienced MCU wranglers aren’t invited to the party; they might just have to broaden their horizons a bit.
To learn more about this interesting paradigm shift, we invited the fine folks at Adafruit to the Hack Chat so the community could get a chance to ask questions about CircuitPython, their in-house Python variant which today runs on more than 400 devices.
Continue reading “The Past, Present, And Future Of CircuitPython”
Often neglected as ‘merely a styling language’, CSS contains a wealth of functions built right into the browser’s rendering engine that can perform everything from animations to typography and even mathematical operations, with more added each year.
In a tutorial [Bramus] takes us through using the trigonometric functions in CSS. These are supported in all major browsers since Chrome 111, Firefox 108 and Safari 15.4. In addition to these trigonometric functions, further mathematical functions are also available, many of whom have been available for years now, such as calc(), min() and max().
Unlike the JavaScript version of the CSS trigonometric functions, the CSS functions accept both angles and radians for the argument. Perhaps the nicest thing about having this functionality in CSS is that it removes the need to add JavaScript for many simple things on a webpage, such as animations, translations and the calculating of offsets and positions. Perhaps most impressive is the provided example by [Ana Tudor] who created an animated Möbius strip using cos() and sin() and a handful of other CSS functions.
None of this is likely surprising to anyone who is somewhat familiar with the depths of CSS, especially after it has been more-or-less proven to be a Turing-complete programming language. Using this power for visual elements does however make a lot of sense considering that CSS was always intended to help with styling and formatting the raw HTML.
Do you use these advanced CSS features already, or is it something you might consider using in the future, possibly over JavaScript versions? Feel free to share your thoughts and experiences in the comments.
(Heading: Code to move items on a circular path around a central point in CSS.)
In the long and winding history of BASIC, it’s sometimes hard to keep track of all the different variants and dialects. Some may still remember TinyBASIC, which was published in 1976 as Palo Alto Tiny BASIC by [Gordon Brandly]. Later, TinyBASIC was modified by a number of people including [Scott Lawrence] who created TinyBASIC Plus (TBP). Inspired by this, [Karl] figured he could improve on TBP by making the original C-based project even easier to port by removing whatever platform dependencies he could find, creating what he calls TinyBasicLike.
The main change is that TinyBasicLike consists out of two C files, with one containing the core code, and the second the platform-specific details that can be used by the core. Although [Karl] started off with the Palo Alto Tiny BASIC-like code by [Scott Lawrence], he decided to make it into his own by making a few alterations, such as adding left and right shift operators, adding an ADDR() function, expanding the features of INPUT and adding multiple logical operators.
In the example STM32F4 project linked on the project page it is demonstrated how to target a new platform with TinyBasicLike. Performance on the STM32F4 Discovery board with a simple counting loop yielded about 6 lines of TBL program code per millisecond. For a 168 MHz STM32 MCU that’s definitely not astounding, but considering how straightforward Tiny BASIC (and TBL as a consequence) is, it’s definitely no slouch.
This is probably a good time to remind that BASIC was the original champion of cross-platform programming and the source of countless fond (and frustrating) memories.
Illumos is an OpenSolaris-derived Unix system, and no Unix is complete without a C compiler or two. And with a name like Portable C Compiler (PCC), you would think that would be a great bet to get up and running on Illumos. That’s probably what [Brian Callahan] thought, too, but found out otherwise.
PCC already generates x86 code, so that wasn’t the problem. It was a matter of reconfiguring the compiler for the environment, ironic since PCC probably started on true Unix but now won’t work with 64-bit Solaris-like operating system. According to the post:
It looks like some time ago someone added configuration for 32-bit x86 and SPARC64 support for the Solaris family. But no one ever tried to support 64-bit x86. So first we had to teach the configure script for both pcc and pcc-libs that 64-bit x86 Solaris
A few days ago, I ran into an online post where someone pointed out the book “Learn to Program with Assembly” and asked if anyone had ever learned assembly language as a first programming language. I had to smile because, if you are a certain age, your first language may well have been assembly, even if it was assembly for machines that never existed.
Of course, that was a long time ago. It is more likely, these days, if you are over 40, you might have learned BASIC first. Go younger, and you start skewing towards Java, Javascript, or even C. It got me thinking, though: should people learn assembly, and if so, when?
Continue reading “Ask Hackaday: Learn Assembly First, Last, Or Never?”
[Johannes 4GNU_Linux] has been filming a video series on how to write Linux device drivers for a couple of years now, but luckily, you won’t need that long to watch them or to create your own driver. He’s added some recent videos to the series, like the one below, but might want to rewind a few years and start at the beginning.
If you build your own hardware for Linux, you’ll probably eventually want to write a driver which runs as a privileged program. While there are many things you can do in user space, for the ultimate control and performance, you can’t beat a driver.
One problem, though, is that drivers can really crash your system in a big way. In the old days, it was common to have a dedicated system for driver development. Today, for many drivers, you can get away with running a virtual machine that you can crash and reload without much trouble.
The videos cover diverse topics like interrupts, completions, polling, and threads. He even uses a Raspberry Pi, which will be very useful for many embedded projects. Of course, the trend these days is to have one driver — like the USB driver — and have it provide user-space access so that everyone doesn’t have to write their own drivers. But, as usual, that only goes so far.
We aren’t sure how many more videos there will be, but if you make it through the first 31, maybe more will be waiting for you. It has been a while since we looked at SPI drivers in Linux. As an example of why you might want to roll your own, consider a custom FPGA driver.
