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PDFIn recent months, Linux® OS and its easily recognized mascot Tux have been popping up more and more in trade publications and in the public media. This attention has reached beyond IT staff, Linux zealots, and self-proclaimed tinkerers, generating curiosity about Linux among a more general population. This article briefly addresses the advantages and disadvantages of using Linux for measurement and control applications and introduces resources and products for developers using Linux.
Figure 1. National Instruments supports LabVIEW 8 and more than 200 data acquisition (DAQ), signal conditioning, and instrument control products on Linux.
What Is Linux?
Simply put, Linux is an operating system. Like other operating systems, its primary task is to help one or more users make the most of computer processors and I/O hardware to accomplish computing tasks. The most significant difference between Linux and the other two most popular operating system families – Windows and Macintosh – is that Linux is available at no cost and the source code is freely available. These differences have proved to be a double-edged sword for test, measurement, and control application developers.
Is It Really “Free”?
Yes, it is true – Linux is available at no cost. Download it, install it, and, within a couple of hours, you can run Linux on an x86-based desktop, laptop, or PXI controller in the development lab. The savings grow with each licensing fee you avoid paying on a deployed instance of the application.
In addition to being available at no cost, Linux is also “open-source” software. It is both written and distributed under the GNU General Public License, making the source code freely available and distributable to the public. Developers can modify and recompile the available source code, to achieve ultimate flexibility. If needed, a developer can even create an application-specific version of Linux to meet bleeding-edge system requirements, such as small, installed footprint or added support for key hardware components.
The decreased cost and flexibility of Linux particularly interest companies and organizations that have been long-time UNIX houses and are looking to transition away from UNIX. With the similarity of Linux to UNIX, many of these groups have realized the aforementioned benefits while minimizing the difficulty of switching operating systems.
Figure 2. A Linux distribution is a unique grouping of a Linux kernel, graphical user interface, application software, and installer.
The “Open-Source” Risk
The dark side of the open-source advantage is that there is currently not much standardization between existing Linux distributions. Anyone can create his or her own customized version of Linux. Currently, different companies and communities maintain more than 300 distributions of Linux. The good news is that there are a handful of leaders, but the variances among distributions can differ widely, with each distribution typically focusing on specific optimizations such as ease of use for the end user, footprint, or stability during embedded execution. This can make understanding the differences among distributions daunting and finding the best distribution challenging.
The absence of standards also prevents many software and hardware vendors from providing reliable support for Linux distributions. Before choosing to develop systems based on Linux, check to make sure that hardware and software vendors can provide support for your system’s components.
Creating Virtual Instruments on Linux
As a leader in PC-based measurement and automation, National Instruments offers software and hardware products for creating virtual instruments on many computing platforms and operating systems, including Linux. In addition to the newest release of NI LabVIEW 8, National Instruments offers driver support for more than 200 measurement hardware devices on supported distributions of Linux.
ANSI C and LabVIEW 8 development is now available using supported devices, including all DAQ, signal conditioning, dynamic signal acquisition, and switching hardware supported by NI-DAQmx driver software for Linux; digital multimeters using NI-DMM driver software for Linux; high-speed digitizers using NI-SCOPE software for Linux; arbitrary waveform generators using NI-FGEN software for Linux; and GPIB and instrument control devices using NI-488.2 software. National Instruments also offers Linux installation support on select PXI and VXI system controllers.
Learn more about the complete National Instruments offering for Linux developers and get answers to frequently asked questions.
This article appeared in the Q1 2006 issue of Instrumentation Newsletter
Linux® is the registered trademark of Linus Torvalds in the U.S. and other countries. Tux penguin is courtesy of Larry Ewing.
Reader Comments | Submit a comment »
Confusing the Kernal with the Distribution.
You really misrepresent Linux as an
operating system when you tell your readers
that there are no standards for it. Linus
Torvalds, as anyone who has tried to get
their 'improvements' added to the kernal can
tell you, is a very demanding judge of
performance and those who test these
submissions and give recommendations are far
more demanding of the released product than
the engineers working for that other OS
manufacturer. Distributions, on the other
hand, are packages of software put together
for the convenience of the intended
customer. Whereas a distribution may have
poorly selected applications packaged with
it, it has nothing to do with the
performance of the Linux kernal. An added
benefit of the Linux system is that the user
has more choice, now and in the future, of
free and purchased software. This is
especially true in light of new revelations
by beta testers, that the 'improved
security' espoused by the Redmondites of
their newest offering really means more
restrictions on would be second source
software developers. Snuffing competition
is more important for them than stability.
Talk about a lack of standards
(read, "ethics")!
- Mar 8, 2006
Licensing conditions not indicated.
As linux is distributed under the GPL V2
license, your article makes no mention of
licensing terms. This could lead people to be
confused over what licensing terms apply to
applications written to employ National
Instruments data aquisition, and what degree
of compatability exists between your
licensing terms and that of the GPL.
Regards,
Morrie.
- Mar 7, 2006
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