Linux Fu: The Windows X11 Connection

The life of a Linux user can be a bit difficult. Sometimes you have to — or want to — run Windows. Why Windows? Sometimes you have a work computer or a laptop that Linux doesn’t support well. Or it might be software. Although there are plenty of programs that can edit, say, Word documents, there’s always that one document that doesn’t quite translate correctly. Things like videoconferencing software sometimes works on Linux but might have fewer features.

So what do you do? You can dual boot, of course, but that’s not very handy. You can run Windows in a virtual machine if you have enough horsepower. There’s also Wine, but that often has its own set of problems with features and stability of complex programs. However, recent versions of Windows provide the Windows Subsystem for Linux (WSL).

With WSL, you can have most of what you like about Linux inside your Windows session. You just have to know how to set it up, and I’m going to show you one way that works for me with reasonably stable versions of Windows 10. Continue reading “Linux Fu: The Windows X11 Connection”

Classroom Surplus Becomes Linux Powerhouse

The SMART Response XE is a handheld computer that was originally sold for use in the classroom as a terminal for pupils taking tests. It’s now cheap enough on the surplus market to have become a target for experimenters, and we’ve seen them with a variety of cool hacks. We particularly like what [chmod775] has done with it, putting a VT100 terminal emulator on the device and hiding a NanoPi Neo Air single board computer in the battery bay. Powered from a USB battery bank, it gives a fully-featured Linux terminal in the palm of the hand. We see it running an Ubuntu LTS  version, and it’s clear that it’s a functional and usable device.

This raises a more abstract question though: We’d guess comparatively few of us write software through an old-style dumb terminal, instead we’re more likely to get our terminal experience at a much more accomplished command line with all the conveniences of a modern desktop surrounding it. How many of us could comfortably return to the limited confines of a VT100 emulator on an odd-sized LCD display? We’d be interested to hear [chmod755]’s experiences using it, because if it retains usability it’s a device we wouldn’t mind having ourselves.

Hungry for more SMART Response XE hacks? Take a look at the BASIC computer, or the spectrum analyser.

WiFiWart Boots Linux, Moves To Next Design Phase

Over the last few months we’ve been keeping an eye on WiFiWart, an ambitious project to develop a Linux single-board computer (SBC) small enough to fit inside a USB wall charger. Developer [Walker] says the goal is to create an easily concealable “drop box” for penetration testing, giving security researchers a valuable foothold inside a target network from which to preform reconnaissance or launch attacks. Of course, we don’t need to tell Hackaday readers that there’s plenty of other things you can do with such a tiny open hardware Linux SBC.

Today we’re happy to report that [Walker] has gotten the first version of the board booted into Linux, though as you might expect given a project of this complexity, there were a few bumps along the way. From the single missing resistor that caused U-Boot to throw up an error to the finer points of compiling the kernel for an embedded board, the latest blog post he’s written up about his progress provides fascinating insight into the little gotchas of bringing up a SBC from scratch.

Once the board was booted into Linux, [Walker] started testing out different aspects of the system. A memory benchmark confirmed the finicky DDR3 RAM was working as expected, and he was able to load the kernel modules for the dual RTL8188 interfaces and connect to a network. While the two WiFi modules are currently hanging off the board’s full-sized USB ports, they will eventually be integrated into the PCB.

Critically, this prototype board is also allowing [Walker] to get an idea of what the energy consumption of the final hardware might be. Even at full tilt, this larger board doesn’t go over 500 mA at 5 VDC; so if he designs the power supply with a maximum output of 1 A, he should have a nice safety margin. As mentioned in the previous post, the plan is currently to put the PSU on its own board, which will allow more effective use of the charger’s internal volume.

With the software and hardware now largely locked in, [Walker] says his attention will be turned towards getting everything small enough to fit into the final form factor. This will certainly be the most challenging aspect of the project, but with a growing community of hackers and engineers lending their expertise to the cause, we’re confident the WiFiWart will soon be a reality.

Linux Fu: Superpowers For Mere Mortals

You can hardly mention the sudo command without recalling the hilarious XKCD strip about making sandwiches. It does seem like sudo is the magic power to make a Linux system do what you want. The only problem is that those superpowers are not something to be taken lightly.

CC-BY-NC-2.5 by [XKCD]
If you are surfing the web, for example, you really don’t want to be root, because if someone naughty takes over your computer they could do a lot more harm with your root password. But still, there are times when you want to run certain commands that are normally root-only and don’t want to bother with a password. Luckily, sudo can handle that use case very easily.

Why?

As a simple example, suppose you like to shut your computer down at the end of the day. You run the shutdown command from the terminal but it doesn’t work because you aren’t root. You then have to do it again with sudo and if you haven’t logged in lately, provide your password. Ugh.

Continue reading “Linux Fu: Superpowers For Mere Mortals”

The Linux Kernel 5.14 Audio Update

You may remember the Pipewire coverage we ran a couple weeks ago, and the TODO item to fix up Firewire device support with Pipewire. It turns out that this is an important feature for kernel hackers, too, because the Alsa changes just got pulled into the 5.14 kernel, and included is the needed Firewire audio work. Shout-out to [Marcan] for pointing out this changeset. Yes, that’s the same as [Hector Martin], the hacker bringing Linux to the M1, who also discovered M1racles. We’ve covered some of his work before.

It turns out that some Firewire audio devices expect timing information in the delivery stream to match the proper playback time for the audio contained in the stream. A naive driver ends up sending packets of sound to the Firewire device that wanted to be played before the packet arrives. No wonder the devices didn’t work correctly. I’m running a 5.14 development kernel, and so far my Focusrite Saffire Pro40 has been running marvelously, where previous kernels quickly turned its audio into a crackling mess.

There is another fix that’s notable for Pipewire users, a reduction in latency for USB audio devices. That one turned out to be not-quite-correct, leading to a hang in the kernel on Torvald’s machine. It’s been reverted until the problem can be corrected, but hopefully this one will land for 5.14 as well. (Edit: The patch was cleaned up, and has been pulled for 5.14. Via Phoronix.) Let us know if you’d like to see more kernel development updates!

Linux Fu: PDF For Penguins

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”

Rocky Linux Is Ready For Prime Time!

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.