It’s Linux – But On An ESP32

July 21, 2021 by Jenny List 44 Comments

GNU/Linux is an open-source marvel that has over the past three decades given us an almost infinitely versatile and powerful UNIX-like operating system. But even it has its limitations, particularly at the lower end of the hardware scale where less fully-featured processors often lack the prerequisites such as a memory management unit. Thus [JuiceRV]’s feat of booting a Linux kernel on an ESP32 microcontroller seems impossible, what’s happening?

The ESP’s dual 32-bit Xtensa cores are no slouch in the processing power department, but without that MMU it’s not an obvious Linux candidate platform. The solution to this problem comes in the form of an emulated RISC-V virtual machine which provides just enough grunt for a Linux 5.0.0 kernel to boot.

By any measure this represents an impressive piece of work, but will this new-found ability to run Linux on a microcontroller take the world by storm? Of course not, unless your tastes run to the very slowest of computing experiences. It is however the essence of the hack, and for that we salute it.

It’s not the first time Linux has run on a microcontroller, in the past someone hooked up a 30 pin SIMM and an SD card to an 8-bit Atmel chip and did it in a similar way with an ARM emulator.

Via CNX Software.

Header image: Ubahnverleih, CC0.

Linux Fu: PDF For Penguins

July 6, 2021 by Al Williams 44 Comments

PostScript started out as a programming language for printers. While PostScript printers are still a thing, there are many other ways to send data to a printer. But PostScript also spawned the Portable Document Format or PDF and that has been crazy successful. Hardly a day goes by that you don’t see some kind of PDF document come across your computer screen. Sure, there are other competing formats but they hold a sliver of market share compared to PDF. Viewing PDFs under Linux is no problem. But what about editing them? Turns out, that’s easy, too, if you know how.

GUI Tools

You can use lots of tools to edit PDF files, but the trick is how good the results will look. Anything will work for this: LibreOffice Draw, Inkscape, or even GIMP. If all you want to do is remove something with a white box or make an annotation, these tools are usually great, but for more complicated changes, or pixel-perfect output, they may not be the right tool.

The biggest problem is that most of these tools deal with the PDF as an image or, at least, a collection of objects. For example, columns of text will probably turn into a collection of discrete lines. Changing something that causes a line to wrap will require you to change all the other lines to match. Sometimes text isn’t even text at all, but images. It largely depends on how the creator made the PDF to begin with. Continue reading “Linux Fu: PDF For Penguins” →

Installing Linux Like It’s 1989

June 30, 2021 by Bryan Cockfield 34 Comments

A common example of the sheer amount of computing power available to almost anyone today is comparing a smartphone to the Apollo guidance computer. This classic computer was the first to use integrated circuits so it’s fairly obvious that most modern technology would be orders of magnitude more powerful, but we don’t need to go back to the 1960s to see this disparity. Simply going back to 1989 and getting a Compaq laptop from that era running again, while using a Raspberry Pi Zero to help it along, illustrates this point well enough.

[befinitiv] was able to get a Raspberry Pi installed inside of the original computer case, and didn’t simply connect the original keyboard and display and then call it a completed build. The original 286 processor is connected to the Pi with a serial link, so both devices can communicate with each other. Booting up the computer into DOS and running a small piece of software allows the computer into a Linux terminal emulator hosted on the Raspberry Pi. The terminal can be exited and the computer will return back to its original DOS setup. This also helps to bypass the floppy disk drive for transferring files to the 286 as well, since files can be retrieved wirelessly on the Pi and then sent to the 286.

This is quite an interesting mashup of new and old technology, and with the Pi being around two orders of magnitude more powerful than the 286 and wedged into vacant space inside the original case, [befinitiv] points out that this amalgamation of computers is “borderline useful”. It’s certainly an upgrade for the Compaq, and for others attempting to get ancient hardware on the internet, don’t forget that you can always use hardware like this to access Hackaday’s retro site.

Continue reading “Installing Linux Like It’s 1989” →

Rocky Linux Is Ready For Prime Time!

June 24, 2021 by Jonathan Bennett 23 Comments

For some small percentage of the Hackaday crowd, our world got turned upside down at the end of last year, when Red Hat announced changes to CentOS. That distro is the official repackage of Red Hat Enterprise Linux, providing a free, de-branded version of RHEL. The big problem was that CentOS 8 support has been cut way short, ending at the end of 2021 instead of the expected 2029. This caused no shortage of consternation in the community, and a few people and companies stepped forward to provide their own CentOS alternative, with AlmaLinux and Rocky Linux being the two most promising. AlmaLinux minted their first release in March, but the Rocky project made the decision to take things a bit slower. The wait is over, and the Rocky Linux 8.4 release is ready.

Not only are there ISOs for new installs, there is also a script to convert a CentOS 8 install to Rocky. Now before you run out and convert all your CentOS machines, there are a few caveats. First, the upgrade script is still being tested and fixed as problems are found. The big outstanding issue is that Secure Boot isn’t working yet. The process of spinning up a new Secure Boot shim and getting it properly signed is non-trivial, and takes time. The plan is to do an 8.4 re-release when the shim is ready, so keep an eye out for that, if you need Secure Boot support.

The future looks bright for enterprise Linux, with options such as Rocky Linux, AlmaLinux, and even CentOS Stream. It’s worth noting that Rocky has a newly formed company behind it, CIQ, offering support if you want it. The Rocky crew is planning a launch party online on June 25th, so tune in if that’s your thing. Regardless of which Linux OS you run, it’s good to have Rocky in the game.

PipeWire, The Newest Audio Kid On The Linux Block

June 23, 2021 by Jonathan Bennett 65 Comments

Raise your hand if you remember when PulseAudio was famous for breaking audio on Linux for everyone. For quite a few years, the standard answer for any audio problem on Linux was to uninstall PulseAudio, and just use ALSA. It’s probably the case that a number of distros switched to Pulse before it was quite ready. My experience was that after a couple years of fixing bugs, the experience got to be quite stable and useful. PulseAudio brought some really nice features to Linux, like moving sound streams between devices and dynamically resampling streams as needed.

Continue reading “PipeWire, The Newest Audio Kid On The Linux Block” →

A Collection Of Linux Tools On Steroids

June 21, 2021 by Al Williams 75 Comments

Sometimes we do things because “that’s the way we’ve always done them.” Screws, for example, had slotted heads in the 1500s and slotted heads are notoriously bad, but despite Robertson in 1907 and Phillips in the 1930s, it took decades for slotted screw heads to become uncommon and they still lurk in a few areas. Many Linux tools we use every day are direct descendants from Unix tools that have been around for almost half a century. We’ve looked at a few more modern alternatives before, and [ibraheemdev] has a GitHub collection of many such tools that’s worth checking out.

Of course, modern doesn’t always mean better. However, the tools in the list do have great features including things that were uncommon in the old days such as the use of color, text-based graphics, and things like git integration.

Continue reading “A Collection Of Linux Tools On Steroids” →

Linux Fu: Databases Are Next-Level File Systems

June 8, 2021 by Al Williams 63 Comments

It is funny how exotic computer technology eventually either fails or becomes commonplace. At one time, having more than one user on a computer at once was high tech, for example. Then there are things that didn’t catch on widely like vector display or content-addressable memory. The use of mass storage — especially disk drives — in computers, though has become very widespread. But at one time it was an exotic technique and wasn’t nearly as simple as it is today.

However, I’m surprised that the filesystem as we know it hasn’t changed much over the years. Sure, compared to, say, the 1960s we have a lot better functionality. And we have lots of improvements surrounding speed, encoding, encryption, compression, and so on. But the fundamental nature of how we store and access files in computer programs is stagnant. But it doesn’t have to be. We know of better ways to organize data, but for some reason, most of us don’t use them in our programs. Turns out, though, it is reasonably simple and I’m going to show you how with a toy application that might be the start of a database for the electronic components in my lab.

You could store a database like this in a comma-delimited file or using something like JSON. But I’m going to use a full-featured SQLite database to avoid having a heavy-weight database server and all the pain that entails. Is it going to replace the database behind the airline reservation system? No. But will it work for most of what you are likely to do? You bet. Continue reading “Linux Fu: Databases Are Next-Level File Systems” →