Hardware

Downsides to Raspberry Pi Alternatives

Kyle Rankin — Wed, 27 Mar 2019 12:00:00 +0000

Learn about some of the risks when choosing an alternative to a Raspberry Pi for your project.

I have a lot of low-cost single-board computers (SBCs) at my house. And, I've written a number of articles for Linux Journal that discuss how I put those computers to use—whether it's controlling my beer fridge, replacing a rackmount file server, acting as a media PC connected to my TV or as an off-site backup server in my RV (plus many more). Even more recently, I wrote a "Pi-ventory" article where I tried to count up just how many of these machines I had in my home.

Although the majority of the SBCs I use are some form of Raspberry Pi, I also sometimes use Pi alternatives—SBCs that mimic the Raspberry Pi while also offering expanded features—whether that's gigabit Ethernet, faster CPUs, SATA ports, USB3 support or any number of other improvements. These boards often even mimic the Raspberry Pi by having "Pi" in their names, so you have Orange Pi and Banana Pi among others. Although Pi alternatives allow you to solve some problems better than a Raspberry Pi, and in many cases they provide hardware with better specifications for the same price, they aren't without their drawbacks. So in this article, I take a look at the downsides of going with a Pi alternative based on my personal experience.

Third-Party Support

The initial Raspberry Pi was a runaway success, and all of the subsequent models have sold incredibly well. There are only a few variants on the Raspberry Pi platform, and later hardware upgrades have done a good job at maintaining backward-compatibility where possible (in particular with overall board dimensions and placement of ports). There also have been only a few "official" Raspberry Pi peripherals through the years (the camera being the best example). When you have this many of a particular hardware device out in the world, and the primary vendor is mostly focused on the hardware itself, you have a strong market for add-ons and peripherals from third parties.

The secondary Raspberry Pi market is full of cases, peripherals and add-on hardware like USB WiFi dongles that promise to be compatible out of the box with earlier models that didn't include WiFi. Adafruit is a good example of an electronics vendor who has jumped into the Raspberry Pi secondary market with a lot of different hobbyist kits that feature the Raspberry Pi as the core computing and electronics platform. That company and others also have created custom add-on shields intended to stack on top of the Raspberry Pi and add additional features including a number of different screen options, sensors and even cellular support. There's even a company that offers a case to turn a Raspberry Pi into a small laptop.

Go to Full Article

Handling Complex Memory Situations

Zack Brown — Wed, 20 Mar 2019 12:00:00 +0000

by Zack Brown

Jérôme Glisse felt that the time had come for the Linux kernel to address seriously the issue of having many different types of memory installed on a single running system. There was main system memory and device-specific memory, and associated hierarchies regarding which memory to use at which time and under which circumstances. This complicated new situation, Jérôme said, was actually now the norm, and it should be treated as such.

The physical connections between the various CPUs and devices and RAM chips—that is, the bus topology—also was relevant, because it could influence the various speeds of each of those components.

Jérôme wanted to be clear that his proposal went beyond existing efforts to handle heterogeneous RAM. He wanted to take account of the wide range of hardware and its topological relationships to eek out the absolute highest performance from a given system. He said:

One of the reasons for radical change is the advance of accelerator like GPU or FPGA means that CPU is no longer the only piece where computation happens. It is becoming more and more common for an application to use a mix and match of different accelerator to perform its computation. So we can no longer satisfy our self with a CPU centric and flat view of a system like NUMA and NUMA distance.

He posted some patches to accomplish several different things. First, he wanted to expose the bus topology and memory variety to userspace as a clear API, so that both the kernel and user applications could make the best possible use of the particular hardware configuration on a given system. A part of this, he said, would have to take account of the fact that not all memory on the system always would be equally available to all devices, CPUs or users.

To accomplish all this, his patches first identified four basic elements that could be used to construct an arbitrarily complex graph of CPU, memory and bus topology on a given system.

These included "targets", which were any sort of memory; "initiators", which were CPUs or any other device that might access memory; "links", which were any sort of bus-type connection between a target and an initiator; and "bridges", which could connect groups of initiators to remote targets.

Aspects like bandwidth and latency would be associated with their relevant links and bridges. And, the whole graph of the system would be exposed to userspace via files in the SysFS hierarchy.

Go to Full Article

Disk Encryption for Low-End Hardware

Zack Brown — Thu, 07 Feb 2019 13:15:15 +0000

by Zack Brown

Eric Biggers and Paul Crowley were unhappy with the disk encryption options available for Android on low-end phones and watches. For them, it was an ethical issue. Eric said:

We believe encryption is for everyone, not just those who can afford it. And while it's unknown how long CPUs without AES support will be around, there will likely always be a "low end"; and in any case, it's immensely valuable to provide a software-optimized cipher that doesn't depend on hardware support. Lack of hardware support should not be an excuse for no encryption.

Unfortunately, they were not able to find any existing encryption algorithm that was both fast and secure, and that would work with existing Linux kernel infrastructure. They, therefore, designed the Adiantum encryption mode, which they described in a light, easy-to-read and completely non-mathematical way.

Essentially, Adiantum is not a new form of encryption; it relies on the ChaCha stream cipher developed by D. J. Bernstein in 2008. As Eric put it, "Adiantum is a construction, not a primitive. Its security is reducible to that of XChaCha12 and AES-256, subject to a security bound; the proof is in Section 5 of our paper. Therefore, one need not 'trust' Adiantum; they only need trust XChaCha12 and AES-256."

Eric reported that Adiantum offered a 20% speed improvement over his and Paul's earlier HPolyC encryption mode, and it offered a very slight improvement in actual security.

Eric posted some patches, adding Adiantum to the Linux kernel's crypto API. He remarked, "Some of these patches conflict with the new 'Zinc' crypto library. But I don't know when Zinc will be merged, so for now, I've continued to base this patchset on the current 'cryptodev'."

Jason A. Donenfeld's Zinc ("Zinc Is Not crypto/") is a front-runner to replace the existing kernel crypto API, and it's more simple and low-level than that API, offering a less terrifying coding experience.

Jason replied to Eric's initial announcement. He was very happy to see such a good disk encryption alternative for low-end hardware, but he asked Eric and Paul to hold off on trying to merge their patches until they could rework them to use the new Zinc security infrastructure. He said, "In fact, if you already want to build it on top of Zinc, I'm happy to work with you on that in a shared repo or similar."

He also suggested that Eric and Paul send their paper through various academic circles to catch any unanticipated problems with their encryption system.

But Paul replied:

Go to Full Article

Using Linux for Logic

Joey Bernard — Fri, 04 Jan 2019 12:30:00 +0000

by Joey Bernard

I've covered tons of different scientific applications you can run on your computer to do rather complex calculations, but so far, I've not really given much thought to the hardware on which this software runs. So in this article, I take a look at a software package that lets you dive deep down to the level of the logic gates used to build up computational units.

At a certain point, you may find yourself asking your hardware to do too much work. In those cases, you need to understand what your hardware is and how it works. So, let's start by looking at the lowest level: the lowly logic gate. To that end, let's use a software package named Logisim in order to play with logic gates in various groupings.

Logisim should be available in most distributions' package management systems. For example, in Debian-based distros, install it with the following command:


sudo apt-get install logisim

You then can start it from your desktop environment's menu, or you can open a terminal, type logisim and press Enter. You should see a main section of the application where you can start to design your logic circuit. On the left-hand side, there's a selection pane with all of the units you can use for your design, including basic elements like wires and logic gates, and more complex units like memory or arithmetic units.

Figure 1. When you first start Logisim, you get a blank project where you can start to design your first logic circuit.

To learn how to start using Logisim, let's look at how to set up one of the most basic logic circuits: an AND gate.

Figure 2. You easily can add logic gates to your circuit to model computations.

If you click the Gates entry on the left-hand side, you'll see a full list of available logic gates. Clicking the AND gate allows you to add them to the design pane by clicking on the location where you want them added. At the bottom of the left-hand side, you'll see a pane that displays the attributes of the selected gate. You can use this pane to edit those attributes to make the gate behave exactly the way you want. For this example, let's change the number of inputs value from 5 to 2. The next step is to add an output pin in order to see when the output is either 1 or 0. You can find pins in the wiring section.

Go to Full Article

The Asus Eee: How Close Did the World Come to a Linux Desktop?

Jeff Siegel — Fri, 02 Nov 2018 13:30:00 +0000

by Jeff Siegel

It was white, not much bigger than my hands held side by side, weighed about as much as a bottle of wine, and it came in a shiny, faux-leather case. It was the $199 Asus Eee 901, and I couldn't believe that a computer could be that powerful, that light and that much fun.

This is the story of the brief, shining history of the Asus Eee, the first netbook—a small, cheap and mostly well-made laptop that dominated the computer industry for two or three years about a decade go. It's not so much that the Eee was ahead of its time, which wasn't that difficult in an industry then dominated by pricey and bulky laptops that didn't always have a hard drive and by desktop design hadn't evolved much past the first IBM 8086 box.

Rather, the Eee was ahead of everyone's time. It ran a Linux operating system with a tabbed interface and splashy icons, and the hardware included wireless, Bluetooth, a webcam and an SSD hard drive—all in a machine that weighed just 2.5 pounds. In this, it teased many of the concepts that tech writer Mark Wilson says we take for granted in today's cloud, smartphone and Chromebook universe.

The Eee was so impressive that even Microsoft, whose death grip on the PC world seemed as if it would never end, took notice. As everyone from Dell to HP to Samsung to Toshiba to Sony to Acer to one-offs and "never-weres" raced netbooks into production, Microsoft offered manufacturers a version of Windows XP (and later a truncated Windows 7) to cram onto the machines. Because we can't have the masses running a Linux OS, can we?

"The Eee gave regular people something they couldn't have before", says Dan Ackerman, a longtime section editor at CNET who wrote some of the website's original Eee and netbook reviews. "Laptops had always been ridiculously expensive. The Eee wasn't, and it gave regular people a chance to buy a laptop that was smaller and more portable and that they could be productive with. I always gave Asus credit—they understood the role of form and function."

Netbook History

The computer world never had really seen anything like the first Eee, which didn't even have a name when it was launched in 2007 (although it later would be called both the 701 and the 4G). In fact, say those who reviewed the 701, it wasn't so much a product but a proof of concept—that Asus could make something that small and that cheap that worked.

There had been small laptops before, of course, like the Intel Classmate PC and the OLPC X0-1, each part of the One Laptop per Child project. But those were specialized machines designed to bring computing and the internet to students throughout the world, and not necessarily consumer products.

Go to Full Article

System76 Announces American-Made Desktop PC with Open-Source Parts

Bryan Lunduke — Thu, 01 Nov 2018 15:01:36 +0000

by Bryan Lunduke

Early in 2017—nearly two years ago—System76 invited me, and a handful of others, out to its Denver headquarters for a sneak peek at something new they'd been working on.

We were ushered into a windowless, underground meeting room. Our phones and cameras confiscated. Seriously. Every word of that is true. We were sworn to total and complete secrecy. Assumedly under penalty of extreme death...though that part was, technically, never stated.

Once the head honcho of System76, Carl Richell, was satisfied that the room was secure and free from bugs, the presentation began.

System76 told us the company was building its own desktop computers. Ones that it designed themselves. From-scratch cases. With wood. And inlaid metal. What's more, these designs would be open. All built right there in Denver, Colorado.

We were intrigued.

Then they showed them to us, and we darn near lost our minds. They were gorgeous. We all wanted them.

But they were not ready yet. This was early on in the design and engineering, and they were looking for feedback—to make sure System76 was on the right track.

They were.

Flash-forward to today (November 1, 2018), and these Linux-powered, made in America desktop machines are finally being unveiled to the world as the Thelio line (which they've been teasing for several weeks with a series of sci-fi themed stories).

The Thelio comes in three sizes:

Thelio (aka "small") — max 32GB RAM, 24TB storage.
Thelio Major (aka "medium") — max 128GB RAM, 46TB storage.
Thelio Massive (aka "large") — max 768GB RAM, 86TB storage.

All three sport the same basic look: part black metal, part wood (with either maple or walnut options) with rounded side edges. The cases open with a single slide up of the outer housing, with easy swapping of components. Lots of nice little touches, like a spot for in-case storage of screws that can be used in securing drives.

In an awesomely nerdy touch, the rear exhaust grill shows the alignment of planets in the solar system...at UNIX Epoch time. Also known as January 1, 1970. A Thursday.

Go to Full Article

New Intel Caching Feature Considered for Mainline

Zack Brown — Wed, 22 Aug 2018 12:07:07 +0000

by Zack Brown

These days, Intel's name is Mud in various circles because of the Spectre/Meltdown CPU flaws and other similar hardware issues that seem to be emerging as well. But, there was a recent discussion between some Intel folks and the kernel folks that was not related to those things. Some thrust-and-parry still was going on between kernel person and company person, but it seemed more to do with trying to get past marketing speak, than at wrestling over what Intel is doing to fix its longstanding hardware flaws.

Reinette Chatre of Intel posted a patch for a new chip feature called Cache Allocation Technology (CAT), which "enables a user to specify the amount of cache space into which an application can fill". Among other things, Reinette offered the disclaimer, "The cache pseudo-locking approach relies on generation-specific behavior of processors. It may provide benefits on certain processor generations, but is not guaranteed to be supported in the future."

Thomas Gleixner thought Intel's work looked very interesting and in general very useful, but he asked, "are you saying that the CAT mechanism might change radically in the future [that is, in future CPU chip designs] so that access to cached data in an allocated area which does not belong to the current executing context wont work anymore?"

Reinette replied, "Cache Pseudo-Locking is a model-specific feature so there may be some variation in if, or to what extent, current and future devices can support Cache Pseudo-Locking. CAT remains architectural."

Thomas replied, "that does NOT answer my question at all."

At this point, Gavin Hindman of Intel joined the discussion, saying:

Support in a current generation of a product line doesn't imply support in a future generation. Certainly we'll make every effort to carry support forward, and would adjust to any changes in CAT support, but we can't account for unforeseen future architectural changes that might block pseudo-locking use-cases on top of CAT.

And Thomas replied, "that's the real problem. We add something that gives us some form of isolation, but we don't know whether next generation CPUs will work. From a maintainability and usefulness POV that's not a really great prospect."

Elsewhere in a parallel part of the discussion, Thomas asked, "Are there real world use cases that actually can benefit from this [CAT feature] and what are those applications supposed to do once the feature breaks with future generations of processors?"

Reinette replied, "This feature is model-specific with a few platforms supporting it at this time. Only platforms known to support Cache Pseudo-Locking will expose its resctrl interface."

To which Thomas said, "you deliberately avoided to answer my question again."

Go to Full Article

The Chromebook Grows Up

Philip Raymond — Fri, 17 Aug 2018 11:30:00 +0000

by Philip Raymond

Android apps meet the desktop in the Chromebook.

What started out as a project to provide a cheap, functional, secure and fast laptop experience has become so much more. Chromebooks in general have suffered from a lack of street-cred acceptance. Yes, they did a great job of doing the everyday basics—web browsing and...well, that was about it. Today, with the integration of Android apps, all new and recently built Chrome OS devices do much more offline—nearly as much as a conventional laptop or desktop, be it video editing, photo editing or a way to switch to a Linux desktop for developers or those who just like to do that sort of thing.

Figure 1. Pixelbook in the Dark

Before I go further, let me briefly describe the Linux road I've traveled, driven by my curiosity to learn and see for myself how much could be done in an Open Source world. I've used Linux and have been a Linux enthusiast ever since I first loaded SUSE in 2003. About three years later, I switched to Ubuntu, then Xubuntu, then Lubuntu, then back to Ubuntu (I actually liked Unity, even though I was fine with GNOME too). I have dual-booted Linux on several Gateway desktops and Dell laptops, with Windows on the other partition. I also have owned a Zareason laptop and most recently, a System 76 laptop—both exclusively Ubuntu, and both very sound, well-built laptops.

Then, since I was due for a new laptop, I decided to try a Chromebook, now that Android apps would greatly increase the chances of having a good experience, and I was right. Chrome OS is wicked fast, and it's never crashed in my first six months of using it. I mention this only to provide some background as to why I think Chrome OS is, in my opinion, the Linux desktop for the masses that's been predicted for as long as I've used Linux. Granted, it has a huge corporate behemoth in the form of Google behind it, but that's also why it has advanced in public acceptance as far as it has. This article's main purpose is to report on how far it has come along and what to expect in the future—it's a bright one!

Chromebooks now have access to Microsoft Office tools, which is a must for those whose employers run only MS Office products. Although Google Docs does a good job with basic document creation and conversion, and although you can create a slide presentation with it, it won't do things like watch or create a PowerPoint presentation. That's where the Microsoft PowerPoint Android app comes in handy. If you need to watch one, simply download the PowerPoint file and open it with PowerPoint (you can do this without paying for Microsoft office). However, if you want to create or edit one, you'll have to pay for a yearly subscription or use your company's subscription.

Go to Full Article

Removing Support for Dead Hardware

Zack Brown — Thu, 05 Jul 2018 12:00:00 +0000

by Zack Brown

Arnd Bergmann submitted a patch to remove the Linux ports for a variety of architectures, including blackfin, cris, frv, m32r, metag, mn10300, score and tile. To do this, he worked directly with the former maintainers of each port to make sure the code removal was done right and didn't break anything in the mainline kernel or anywhere else.

The bottom line was that no one used those architectures anymore. He offered his analysis of why this had happened, saying:

It seems that while the eight architectures are extremely different, they all suffered the same fate: There was one company in charge of an SoC line, a CPU microarchitecture and a software ecosystem, which was more costly than licensing newer off-the-shelf CPU cores from a third party (typically ARM, MIPS, or RISC-V). It seems that all the SoC product lines are still around, but have not used the custom CPU architectures for several years at this point. In contrast, CPU instruction sets that remain popular and have actively maintained kernel ports tend to all be used across multiple licensees.

Linus Torvalds had no objection to ripping those architectures out of the kernel, but he did say, "I'd like to see that each architecture removal is independent of the others, so that if somebody wants to resurrect any particular architecture, he/she can do so with a revert."

Linus pulled the patch into the main kernel tree and noted with glee that it took a half-million lines of code out of the kernel.

Linus was not the only one who wanted to ensure the possibility of easily resurrecting those architectures. Geert Uytterhoeven wanted to know exactly what would be required, since he had an interest in the formerly removed and later resurrected arch/h8300 architecture, currently still in the kernel and going strong. And he pointed out, "In reality, a resurrection may not be implemented as a pure revert, but as the addition of a new architecture, implemented using modern features."

To which Pavel Machek complained, "By insisting on new features instead of pure revert + incremental updates, you pretty much make sure resurrection will not be possible."

But Arnd pointed out, "now that the other architectures are gone, a lot of changes can be done more easily that will be incompatible with a pure revert, so the more time passes, the harder it will get to do that."

And he added, "Some of the architectures (e.g. tile or cris) have been kept up to date, but others had already bitrotted to the point where they were unlikely to work on any real hardware for many releases, but a revert could still be used as a starting point in theory."

Go to Full Article

Open Hardware: Good for Your Brand, Good for Your Bottom Line

VM Brasseur — Wed, 20 Jun 2018 12:15:15 +0000

by VM Brasseur

With the rise of IoT, we're inside a short window where "open" is a strong differentiator for hardware products. Is your company ready to take advantage of it?

I don't know how to put this, but Hardware is kind of a Big Deal, and thanks to the Internet of Things (aka IoT), it's getting bigger every year. The analyst firm IDC expects spending on IoT to reach nearly $800 billion USD by the end of 2018. A study by Intel shows that by 2025, the global worth of IoT technology might be as high as more than $6 trillion USD; whereas Forbes reports that the global market could be nearly $9 trillion USD in 2020.

These statistics are based on the traditional model of closed design and development of the chips, boards and objects that will make these devices a reality. However, what if hardware developers were to learn from and leverage the popularity of free and open-source software (aka FOSS)? What if the future of IoT were Open? It's my belief that the device developers who apply the lessons of FOSS to hardware development will be those best positioned to become the powerhouses of that $9 trillion market. Similarly to software, open hardware will be seen first as a differentiator (rather than an eccentricity) and later, as the industry matures, as the default operating mode for hardware development.

Go to Full Article