The “less is more” approach to Embedded Linux toolkits

Making use of the standard Linux installation and development procedures is not necessarily a bad thing, and this suggests the second general approach to Embedded Linux toolkits. The standard Linux workflow is not unusable — it just has chaotic documentation, and could use some utilities oriented toward deploying Linux in embedded… applications. A very reasonable approach would therefore be to package Linux, add some utilities, and provide excellent documentation on the development process.

This is the approach taken by LynuxWorks with their BlueCat product. The amount of code added by LynuxWorks for this product is actually quite small; primarily consisting, as we shall see, of the BlueCat OS Loader (itself simply a Linux implementation with the ability to load another Linux system) and some fairly simple command-line utilities for constructing and deploying kernels and filesystem images. Most significantly, the entire process is extraordinarily well documented in the User's Guide, resulting in a complete and usable system.

The general approach of making the fewest possible modifications to the standard Linux workflow has much to commend it. The most obvious advantage is that it requires the least effort on the part of the toolkit vendor. Start with Linux, add a few command-line tools, document it carefully and thoroughly, and you've got a product.

But the approach has other advantages . . .

• A toolkit that must track the progress of Linux chooses to modify Linux at its peril, since any modifications will have to be revisited when new versions of Linux become available. So the more it diverges from the Linux standard, the greater the resulting maintenance effort over time. This maintenance burden from incompatible versions is the usual argument used against those who predict that Linux itself will fork into numerous versions, and it holds for Embedded Linux no less than Linux in any other form.

• A simple Embedded Linux toolkit also has the advantage of appealing to current Linux users, as they need only learn the tools specific to Embedded Linux deployment.

• Finally, the approach of simple changes to Linux is more likely to add to the pool of open source code Linux code, since the utilities are likely to build on open source tools already available; as we will see, the BlueCat OS Loader is one example.

So it could be that “less is more” when either designing or shopping for an Embedded Linux toolkit.

Installing the BlueCat toolkit

BlueCat is available in Linux-hosted and Windows-hosted versions. The Windows-hosted version seems to be essentially identical to the Linux-hosted one, but running under Cygwin. One can hardly blame LynuxWorks for attempting to appeal to the larger Windows user base, and the Cygwin port could not have taken much effort to produce; but it seems obvious that the most favorable platform from which to deploy Linux-based devices is Linux. Suffice to say that this review concerns only the Linux-hosted version of BlueCat.

Host system requirements for BlueCat are refreshingly modest: '386 processor, 16MB RAM, CD-ROM drive, and 900 MB hard drive space. The documentation lists a requirement of Red Hat 6.1 or 6.2, or TurboLinux workstation 6.0; though as we will see next, BlueCat should work on almost any x86-based Linux distribution.

Installation of BlueCat is a simple process, consisting only of making a directory and running the CD-ROM based install script from that directory. The entire system is installed at this directory; and a SETUP.sh script, to be executed in a shell whenever BlueCat is to be used, is produced. Among other things, this script sets up an alternative RPM environment applying only to the BlueCat installation. That is, after SETUP.sh is run, rpm commands refer to the BlueCat package database, not to the desktop host's rpm database, if any.

This simple installation design is remarkably clever and useful. It instantly expands the range of host Linux distributions to include nearly any that can run a shell script. Thus, for example, Debian systems should be able to host BlueCat development with no effort from LynuxWorks. It also makes BlueCat admirably easy to uninstall; you've got to respect a software package having a documented uninstallation procedure consisting of “rm -rf $BLUECAT_PREFIX”. Finally, it avoids installation problems stemming from RPM incompatibilities such as those I encountered with Hard Hat. I quickly became accustomed to the BlueCat environment. I think most new users will as well, though some familiarity with the Linux command-line environment is a must.

So, BlueCat installation is simple enough that virtually nothing can go wrong.

— Continued —

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Story navigation . . .

• Part 1: Toolkit strategies
  
• Part 2: The “less is more” approach to Embedded Linux toolkits
  
• Part 3: Development Process
  
• Part 4: Other observations

 
This article was originally published on LinuxDevices.com and has been donated to the open source community by QuinStreet Inc. Please visit LinuxToday.com for up-to-date news and articles about Linux and open source.