Fast, small, lightweight—and still a full-featured GNU/Linux: Puppy Linux combines a complete set of applications with great flexibility, yet it requires minimal hardware. This article introduces this increasingly popular GNU/Linux distribution.

Which GNU/Linux?

The GNU/Linux operating system comes in hundreds of flavors or distributions. All are essentially different packaging of the same base software, assembled and adapted for different purposes. Among the features that distinguish the many distros are the user interface, bundled applications, tools, system requirements, and the methods for installing the basic system and additional applications.

Each GNU/Linux distribution has its own personality and strengths. Puppy Linux offers a full-featured, high performance system that doesn’t require state of the art hardware. Puppy’s goals aim at creating a distribution that:

• contains all the applications needed for daily use
• has good performance
• requires minimal system resources
• is highly reliable—“it just works”
• is easy to install and boot from any allowable media (hard disk, flash drives, USB devices, CDs, DVDs, CD/RWs, Zip disks, the network card, et al)
• Easy to use

Read this list carefully and you’ll notice that the third goal directly conflicts with the first two. How can a system offer all the applications most users need, perform well, and still run on low end hardware? Puppy’s solution to this paradox underlies its success.

Puppy is not based on any other GNU/Linux distribution. It is not a “remastered” version of some other GNU/Linux. It was created, file by file, from scratch several years ago specifically to meet the goals above. And so it attains them.

I will discuss Puppy in terms of its goals. Before I start, one note: there are several versions of Puppy as well as a number of derivatives called Puplets. This discussion represents them all.

Applications

Puppy’s primary goal is to include all the applications users normally require, be easy to use, and still perform well even on limited hardware. How can it do that?

Part of the answer lies in its selection of applications. Puppy includes programs for every need—but it carefully picks those that are the most resource efficient. These include everything from office applications to personal information management, from multimedia to web access, from networking to instant messaging. The sample Puppy screens in figures 1 and 2 show various apps being accessed.

Figure 1: Accessing Puppy’s Mulimedia Applications

Figure 2: Some of Puppy’s Utilities

At every turn, Puppy chooses small, lightweight applications. For example, for office work the system includes the Abiword word processor, the Gnumeric spreadsheet, and GsView to display PDF and Postscript files. These applications meet the needs of most users, yet they are way more resource efficient than their Microsoft Office and OpenOffice.org alternatives. Since they are file format compatible with these competing applications, they make reasonable replacements.

Here’s another example of this principle at work. The default browser Puppy uses, called Dillo, runs in only 350 kilobytes. Contrast this to current versions of Internet Explorer or Firefox, which can easily consume many megabytes of memory. Yet for most users’ needs Dillo works just fine. If for some reason you prefer some other browser, you can easily add Firefox, SeaMonkey, Mozilla, Opera, Flock, or almost any other browser. Get the idea?

The major difference between Puppy Linux and its derivatives are in the area of bundled applications. Various Puplets add specific applications like OpenOffice.org, Skype, Firefox, Apache, or many others. I sometimes configure PCs donated to charity, and I’ve found it easy to select a version or derivative of Puppy that bundles the required applications. Check out the apps included in the various Puplets here and here.

Adding applications

Beyond the included applications, a key difference among GNU/Linux distributions is how easy it is to add extra applications to the base system. Can applications be downloaded and installed automatically? Almost any GNU/Linux—including Puppy—allows you to download and compile applications from source code, but most users don’t have the time or the expertise for this. A package manager makes installing additional applications infinitely easier.

Another important factor is how many easily-installed applications are available. A package manager is only as valuable as the apps it can install. A large pool of applications from which to select means greater value.

Puppy’s package manager is called PETget. Figure 3 shows its main interface panel. Simply select the apps you want to install and tell whether you are installing them from the Puppy Live CD or from the internet. The software does the rest.

Figure 3: Adding applications with PETget

PETget also installs many packages outside the official Puppy distribution. These packages are put together by the Puppy community and are often referred to as DotPups.

The official Puppy Live CD distribution includes over 500 packages. DotPups add another couple of hundred (see here and here). The result is that PETget easily installs any mainstream GNU/Linux application.

You can create your own customized version of Puppy Linux using a tool called Puppy Unleashed. With it you create your own Puppy live CD (a bootable CD) with the applications you select from its 500 packages. This way you can quickly customize Puppy into your own version for your organization.

Performance

One secret to Puppy’s performance is its careful selection of lean but mean applications. The other is that Puppy runs everything from memory. The operating system and applications reside in RAM and run from there. Memory access is orders of magnitude faster than disk access so running everything from RAM coaxes reasonable performance even from underpowered computers.

For example, this web page lists start-up times for Puppy running on a 433MHz PC. The PC has only 128MB of RAM and a 128MB compact flash card, and no hard drive (Puppy knows to minimize writes to the flash device to prolong its life). Most applications start in less than a second on this PC. Here are timings for some of the bigger, slower applications as listed on that web page:

Start-up times for applications