GNOME

Running GNOME in a Container

Adam Verslype — Wed, 07 Aug 2019 19:00:00 +0000

Containerizing the GUI separates your work and play.

Virtualization has always been a rich man's game, and more frugal enthusiasts—unable to afford fancy server-class components—often struggle to keep up. Linux provides free high-quality hypervisors, but when you start to throw real workloads at the host, its resources become saturated quickly. No amount of spare RAM shoved into an old Dell desktop is going to remedy this situation. If a properly decked-out host is out of your reach, you might want to consider containers instead.

Instead of virtualizing an entire computer, containers allow parts of the Linux kernel to be portioned into several pieces. This occurs without the overhead of emulating hardware or running several identical kernels. A full GUI environment, such as GNOME Shell can be launched inside a container, with a little gumption.

You can accomplish this through namespaces, a feature built in to the Linux kernel. An in-depth look at this feature is beyond the scope of this article, but a brief example sheds light on how these features can create containers. Each kind of namespace segments a different part of the kernel. The PID namespace, for example, prevents processes inside the namespace from seeing other processes running in the kernel. As a result, those processes believe that they are the only ones running on the computer. Each namespace does the same thing for other areas of the kernel as well. The mount namespace isolates the filesystem of the processes inside of it. The network namespace provides a unique network stack to processes running inside of them. The IPC, user, UTS and cgroup namespaces do the same for those areas of the kernel as well. When the seven namespaces are combined, the result is a container: an environment isolated enough to believe it is a freestanding Linux system.

Container frameworks will abstract the minutia of configuring namespaces away from the user, but each framework has a different emphasis. Docker is the most popular and is designed to run multiple copies of identical containers at scale. LXC/LXD is meant to create containers easily that mimic particular Linux distributions. In fact, earlier versions of LXC included a collection of scripts that created the filesystems of popular distributions. A third option is libvirt's lxc driver. Contrary to how it may sound, libvirt-lxc does not use LXC/LXD at all. Instead, the libvirt-lxc driver manipulates kernel namespaces directly. libvirt-lxc integrates into other tools within the libvirt suite as well, so the configuration of libvirt-lxc containers resembles those of virtual machines running in other libvirt drivers instead of a native LXC/LXD container. It is easy to learn as a result, even if the branding is confusing.

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About ncurses Colors

Jim Hall — Thu, 13 Dec 2018 13:00:00 +0000

by Jim Hall

Why does ncurses support only eight colors?

If you've looked into the color palette available in curses, you may wonder why curses supports only eight colors. The curses.h include file defines these color macros:


COLOR_BLACK
COLOR_RED
COLOR_GREEN
COLOR_YELLOW
COLOR_BLUE
COLOR_MAGENTA
COLOR_CYAN
COLOR_WHITE

But why only eight colors, and why these particular colors? At least with the Linux console, if you're running on a PC, the color range's origins are with the PC hardware.

A Brief History of Color

Linux started as a PC operating system, so the first Linux console was a PC running in text mode. And to understand the color palette on the PC console, you need to go all the way back to the old CGA days. In text mode, the PC terminal had a color palette of 16 colors, enumerated 0 (black) to 15 (white). Backgrounds were limited to the first eight colors:

0. Black
1. Blue
2. Green
3. Cyan
4. Red
5. Magenta
6. Brown
7. White ("Light Gray")
8. Bright Black ("Gray")
9. Bright Blue
10. Bright Green
11. Bright Cyan
12. Bright Red
13. Bright Magenta
14. Yellow
15. Bright White

These colors go back to CGA, IBM's Color/Graphics Adapter from the earlier PC-compatible computers. This was a step up from the plain monochrome displays; as the name implies, monochrome could display only black or white. CGA could display a limited range of colors.

CGA supports mixing red (R), green (G) and blue (B) colors. In its simplest form, RGB is either "on" or "off". In this case, you can mix the RGB colors in 2x2x2=8 ways. Table 1 shows the binary and decimal representations of RGB.

Table 1. Binary and Decimal Representations of RGB

000	(0)	Black
001	(1)	Blue
010	(2)	Green
011	(3)	Cyan
100	(4)	Red
101	(5)	Magenta
110	(6)	Yellow
111	(7)	White

To double the number of colors, CGA added an extra bit called the "intensifier" bit. With the intensifier bit set, the red, green and blue colors would be set to their maximum values. Without the intensifier bit, each RGB value would be set to a "midrange" intensity. Let's represent that intensifier bit as an extra 1 or 0 in the binary color representation, as iRGB (Table 2).

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Introducing Genius, the Advanced Scientific Calculator for Linux

Joey Bernard — Fri, 05 Oct 2018 11:30:00 +0000

by Joey Bernard

Genius is a calculator program that has both a command-line version and a GNOME GUI version. It should available in your distribution's package management system. For Debian-based distributions, the GUI version and the command-line version are two separate packages. Assuming that you want to install both, you can do so with the following command:


sudo apt-get install genius gnome-genius

If you use Ubuntu, be aware that the package gnome-genius doesn't appear to be in Bionic. It's in earlier versions (trusty, xenial and arty), and it appears to be in the next version (cosmic). I ran into this problem, and thought I'd mention it to save you some aggravation.

Starting the command-line version provides an interpreter that should be familiar to Python or R users.

Figure 1. When you start Genius, you get the version and some license information, and then you'll see the interpreter prompt.

If you start gnome-genius, you'll see a graphical interface that is likely to be more comfortable to new users. For the rest of this article, I'm using the GUI version in order to demonstrate some of the things you can do with Genius.

Figure 2. The GUI interface provides easy menu access to most of the functionality within Genius.

You can use Genius just as a general-purpose calculator, so you can do things like:


genius> 4+5
= 9

Along with basic math operators, you also can use trigonometric functions. This command gives the sine of 45 degrees:


genius> sin(45)
= 0.850903524534

These types of calculations can be of essentially arbitrary size. You also can use complex numbers out of the box. Many other standard mathematical functions are available as well, including items like logarithms, statistics, combinatorics and even calculus functions.

Along with functions, Genius also provides control structures like conditionals and looping structures. For example, the following code gives you a basic for loop that prints out the sine of the first 90 degrees:


for i = 1 to 90 do (
   x = sin(i);
   print(x)
)

As you can see, the syntax is almost C-like. At first blush, it looks like the semicolon is being used as a line-ending character, but it's actually a command separator. That's why there is a semicolon on the line with the sine function, but there is no semicolon on the line with the print function. This means you could write the for loop as the following:

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Organizing a Market for Applications

Sriram Ramkrishna — Fri, 24 Aug 2018 13:08:08 +0000

by Sriram Ramkrishna

The "Year of the Desktop" has been a perennial call to arms that's sunken into a joke that's way past its expiration date. We frequently talk about the "Year of the Desktop", but we don't really talk about how we would achieve that goal. What does the "Year of the Desktop" even look like?

What it comes down to is applications—rather, a market for applications. There is no market for applications because of a number of cultural artifacts that began when the Free Software was just getting up on wobbly legs.

Today, what we have is a distribution-centric model. Software is distributed by an OSV (operating system vendor), and users get their software directly from there via whatever packaging mechanism that OSV supports. This model evolved, because in the early-to-mid 1990s, those OSVs existed to compile the kernel and userspace into a cohesive product. Packaging of applications was the next step as a convenience factor to save users from having to compile their own applications, which always was a hit-or-miss endeavor as developers had different development environment from the users. Ultimately, OSVs enjoyed being gatekeepers as part of keeping developers honest and fixing issues that were unique to their operating system. OSVs saw themselves as agents representing users to provide high-quality software, and there was a feeling that developers were not to be trusted, as of course, nobody knows the state of their operating system better than they would.

However, this model represented a number of challenges to both commercial and open-source developers. For commercial developers, the problem became how to maximize their audience as the "Linux" market consisted of a number of major OSVs and an uncountable number of smaller niche distributions. Commercial application developers would have to develop multiple versions of their own application targeted at various major distributions for fear of missing out on a subset of users. Over time, commercial application developers would settle on using Ubuntu or a compressed tar file hosted on their website. Various distributions would pick up these tar balls and re-package them for their users. If you were an open-source developer, you had the side benefit of distributions picking up your work automatically for you and packaging them if you successfully enjoyed a large following. But they faced the same dilemma.

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Gnome 3.2 More Evolution than Revolution

Michael Reed — Mon, 03 Oct 2011 13:00:00 +0000

by Michael Reed

Gnome 3.2 has been released. This time around, the developers have focused on a large number of small improvements rather than big, headline features. That said, there are a couple of interesting new additions in the areas of web integration and personal data management.

Adhering to a six month release schedule, this is the first major Gnome release since version 3.0 debuted in April this year. Rival desktop environments KDE4 (released Jan 2008) and Gnome 3 have something in common in that they were both quite heavily criticized upon release. However, the situation isn’t exactly the same because KDE 4.0 was, arguably, unusable upon release in addition to being a huge departure from the previous series. By contrast, most of the criticism of Gnome 3 has centered on the new user interface and seems to be subject to personal taste. Therefore, it’s not surprising that most of the work seems to have gone into improving refining the new shell.

Sure enough, in the opening section of the official Gnome 3.2 announcement, entitled “Evolution” we are told:

“Based on user feedback, lots of small changes have been made to give a smoother experience in GNOME 3.2.”

See the appropriate section of the the release notes for the full list of improvements. Notable additions include the new Contacts application, the instant image previews in the file manager and the new color management feature. Generally, everything has been spruced up, refined or subjected to greater integration with the whole.

The default theme is a dark one, and overall, Gnome 3.2 now shares quite a bit with KDE4 in the looks department.

Dark blue hues are prominent in the default scheme of the Suse Gnome 3.2 Live CD.

However, despite the focus on refinement rather than new features per se there are two fairly major new features that both relate to web integration.

Sticking with plan A: The old task bar and application launcher of Gnome 2 have been replaced by icons that run down the side of the screen. Some love it; some hate it.

Online Accounts

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Ubuntu Tweak 0.6 Enters beta

Michael Reed — Thu, 29 Sep 2011 13:00:00 +0000

by Michael Reed

There are a wealth of changes which can be made to an Ubuntu system that sit in a category that is half way between the obscure and the genuinely useful. Ubuntu Tweak is utility that exposes these options with a handy GUI.

At time of writing the Ubuntu Tweak 0.6 beta can be installed by using the PPA on the website (see this page).

Ubuntu Tweak may be runnable on other Ubuntu powered desktops or even other distros, but it’s clear that it is aimed squarely at users of stock Ubuntu who like to fiddle. There look to be about 100 options which are divided into three main categories which are then divided into further subcategories:

Startup (Login Settings, Session Control)

Desktop (Compiz Settings, Desktop Icon Settings, GNOME Settings, Window Manager Settings)

System (Nautilus Settings, Power Manager Settings, Security Related, Workarounds)

Version 0.6 has switched to an icon pallet interface rather than the list based interface of previous versions. The options themselves could all be classed as useful but not essential. For those of you who haven’t used Ubuntu Tweak before, I’ll pick out some features to give you a flavor of what’s available.

It’s possible to toggle the startup sound, alter the background image of the GDM login screen, remove the restart icon from the Gnome menu and suppress the restart confirmation dialog. The window manager tweaks move into KDE territory as you can tweak things like the actions of different mouse buttons on window title bars and other areas of the user interface. Under the System section, there are options to control whether the system should become locked when power management blanks the screen and you can force Nautilus to always use the location entry bar rather than the path bar.

Some some of the janitor tools. It's amazing how often purging a cache can resolve a problem. As ever with Ubuntu Tweak, one begins to wonder if these features should be made standard in Ubuntu.

There are many other options, and despite the level of detail offered, the actual navigation between them is perfectly simple thanks to the arrangement of sections and subsections.

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Linus Ditches KDE and Gnome (so what?)

Michael Reed — Fri, 26 Aug 2011 15:16:17 +0000

by Michael Reed

Having made an earlier defection from KDE to Gnome, Linus Torvalds has now rejected both in favor of Xfce. It’s only natural that the actions of the creator of the Linux kernel would attract extra scrutiny, and I think that his decision is reflective of a wider disenchantment amongst long-term Linux users.

So is this post a sky-is-falling complain-fest? Not at all. It might be time for some of us to say, “I don’t like the way that the big two DEs are shaping up, so, I’m going to use something else.”

There was a time when KDE was the desktop for geeks who liked an intricate, customizable interface and Gnome had found its niche as a business desktop. No prizes for guessing which one Linus chose. However, upon the introduction of KDE4, he jumped ship in favor of Gnome 2. He stated that he was disappointed with the performance and reliability of KDE4, in addition to being unconvinced about the new direction that the developers were taking.

He made the announcement of his latest defection via Google+. His first remark was fairly benign:

“While you are at it, could you also fork gnome, and support a gnome-2 environment?”

but then he followed up with some more specific and scathing criticisms:

“I want my sane interfaces back. I have yet to meet anybody who likes the unholy mess that is gnome-3.”

“In gnome3, the developers have apparently decided that it's "too complicated" to actually do real work on your desktop, and have decided to make it really annoying to do.”

“I'm using Xfce. I think it's a step down from gnome2, but it's a huge step up from gnome3. Really.”

Ouch. But also... not ouch. I think that there’s a positive side to all of this. Linus wants to get back to what he considers to be his favorite era of the Linux desktop. What we’re talking about here is a desktop that uses an interface mechanic that is reminiscent of both MacOS and Microsoft Windows and that favors a modular approach to application selection. KDE4 and Gnome 3 are breaking with traditional desktop mechanics while introducing some new elements. KDE4 fails on the second criteria of the the “classic” Linux DE as it will increasingly make use of highly integrated applications.

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When is a Gnome Not a Gnome? In Ubuntu 11.04!

Shawn Powers — Wed, 27 Oct 2010 13:00:00 +0000

by Shawn Powers

At the Ubuntu Devloper Summit on Monday, it was announced that Ubuntu 11.04 will ship with Unity as its default shell. It will still focus on Gnome applications, and depend heavily on the Gnome libraries -- but the default interface will be Unity. For those unfamiliar with Unity, it's the default shell for the Netbook Edition of Ubuntu.

Does Canonical have the right to abandon the Gnome shell for their flagship product? Of course they do, it's their distribution. Heck, they kept it brown for years even when teased incessantly. Whether you love or hate the decision to move away from the Gnome shell in favor of Unity, it's Canonical's right to do as they see fit. Of course, it's easy to change the default shell, much like it's easy to change the default applications they install. To be frank, I dislike most of the default application choices in Ubuntu, yet the OS is so solid, I just tweak it a bit and I'm happy.

For browsing, I prefer Chromium over the default Firefox. I prefer Pidgin over Empathy. For music I like Banshee. For Twitter I install Twhirl. None of those tweaks cause problems with Ubuntu, and most integrate quite nicely even if they're not the default choices. So what does the switch to Unity mean for most users?

Not much.

Granted, it will be a little different to use, but most users shouldn't see much of a difference in functionality. There is some question as to whether Ubuntu can still call themselves a "Gnome-based Distribution", since they're really using Unity as their default user experience. That seems more an argument of semantics though, and won't matter much to the end user.

So what are your thoughts on the switch to Unity? Is it a good move? Bad move? Arrogant, power-flaunting, communist-loving, puppy-kicking move? Or do you not really care? Personally I fall in the latter camp. If I don't like Unity, I'll just install a different option. This is Linux after all, and we can do whatever we want!

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Spotlight on Linux: Parsix 3.6 (RC)

Susan Linton — Wed, 25 Aug 2010 12:00:00 +0000

by Susan Linton

Parsix GNU/Linux is a great little distro hailing from the exotic lands of Persia. It features a lovely customized GNOME desktop and lots of handy applications. It reminds folks of Ubuntu in many ways and is often described as a nice alternative to Ubuntu.

Parsix made its debut soon after the first release of Ubuntu and long before Ubuntu reached any measurable level of popularity. This is why its resemblance to Ubuntu may be coincidental, but this resemblance is so strong that one can't help but think its intentional. Regardless, earlier incarnations featured the same orangy-brown theming and later, around version 1.0, it looked very much like Ubuntu Studio. These days, with version 3.6rc, it looks like Ubuntu again and their attempt to slightly mimic Mac OS X. Whatever the developers' intentions, Parsix always appears polished and unobtrusive.

Appearance speculation aside, Parsix offers a full selection of software. Linux 2.6.32.16 with TuxOnIce suspension/hibernation and Kon Kolivas's BFS patches, X.Org 7.5 (server 1.7.7), GCC 4.4.4, and GNOME 2.30.2 form the 3.6 RC foundations. Some of the software includes Compiz 0.8.4, OpenOffice.org 3.2.1, GIMP 2.6.8, Iceweasel 3.5.1, Evolution, Empathy, Liferea, XawTV, VLC, Exaile, Brasero, and several GNOME games. It also comes with a varied selection of handy system tools and utilities. Parsix uses Synaptic and APT for package management with Parsix official and multimedia repositories enabled. Debian Testing and Parsix security is available and can be enabled if desired.

Parsix is based on Debian Testing with elements of Kanotix and Knoppix still around here and there. It defaults to English, but supports several other languages such as Finnish, French, German, Italian, and, of course, Persian. The image ships as an installable live DVD and versions are available for 32-bit or 64-bit systems. The installer is easy-to-use, fast, and reliable. Handy but perhaps slightly outdated documentation is available such as the User's Guide and an Installation walkthrough. There is also an online Forum for chatting or seeking assistance.

Parsix isn't perfect. Wireless Ethernet can require manual configuration, some NVIDIA chips might be problematic, and Iceweasel can be a bit finicky. But Parsix ships with a nice selection of applications and most multimedia works out of box. This release candidate still has a few issues, but stable releases usually perform very well. Parsix would be a good distribution for new users, those looking for an alternative to Ubuntu, or anyone who enjoys distro hoppin'.

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