Archive for February, 2018

Survey Says: The Commercial RTOS Business is Doomed

Thursday, February 22nd, 2018 Michael Barr

Nearly two decades years ago I was the moderator of an interesting Embedded Systems Conference panel discussion titled “The Great RTOS Debate: Buy or Roll Your Own?” At that time, near the turn of the century, the market for commercial real-time operating systems (RTOSes) was growing rapidly year over year.

The big trend then was away from custom-written “proprietary” kernels toward commercial RTOSes typically licensed with a per unit royalty. From 1997 until their merger in 2000, Wind River and Integrated System together dominated this part of the market. According to surveys taken at the time, either VxWorks or pSOS was the operating system of choice for about 1 in 4 new embedded systems designs.

As embedded Linux entered the market in full and that merger took place, the market was divided roughly as follows: 39% no OS, 31% commercial RTOS, 18% proprietary OS, and 12% Linux.

The selection of operating systems by embedded systems designers has changed considerably since then. According to a preliminary analysis of data collected in Barr Group’s 2018 Embedded Systems Safety & Security Survey there are still quite a few new systems that run “no operating system” on their primary processor. However, this is down from 39% to just 22%. Use of proprietary operating systems is also down about half over the intervening 18 years, from 18% to just 8%.

The most popular category of actual operating system is now Linux at 22%, which is a change from prior years when “RTOS” (an aggregate of those paying for a commercial RTOS and those provided an operating system from chip vendor, which now ranks behind Linux at 19%) was most popular. Following ever more closely on the heels of those “commercial” RTOSes are the open source operating systems (e.g., FreeRTOS) that lack licensing fees.

We can get some sense of the range in the architecture of embedded systems by comparing the rankings of the five most popular operating system choices on the primary processor as the total number of processors goes up. As shown in the table below, the percentage of designers writing their own “proprietary” operating system is about the same (7-9%) regardless of processor count. But Linux clearly becomes a much more popular choice (climbs from 11% to 32%) as the number of processors increases, while “open source” and “no operating system” drop in popularity.

rtos_use_by_cpu_count

But it’s also worth looking at the timeline trend over these years, as I have assembled in the following graph from survey data compiled from 2005-2014 by Embedded.com and in the last three years by Barr Group.

rtos_use_trend_long_term

What I make of all of this is that those who depend for their livelihood on operating system licensing fees from designers of embedded systems should start looking for other sources of income.

What other trends do you see?

C: The Immortal Programming Language

Thursday, February 22nd, 2018 Michael Barr

Barr Group’s 2018 Embedded Systems Safety & Security Survey is now closed and I am in the midst of analyzing the data. This year a portion of my analysis is focused on multi-year trends. One trend that really stands out to me is that the C programming language refuses to give up the ghost.

A longitudinal study of survey data spanning almost a decade and a half shows that C remains the primary programming language of embedded software. Remarkably, in that time C has actually gained market share from 50% to about 70%–at the expense of assembly, C++, and Java.

The graph below shows the relevant data from 2005 through 2018. The first decade of this data is drawn from annual surveys published by the publishers of Embedded.com with the most recent data coming from Barr Group’s annual survey. Each of these surveys of embedded systems designers phrased the relevant question similarly, either “My current embedded project is programmed mostly in [pick one]” or “What is the primary programming language for your current project? [pick one]”.

Language Use Trend Plot

It makes total sense that the use of assembly language as a primary programming language is falling. The last time I wrote an embedded program mostly in assembly was about twenty years ago. Of course, there will always be some low level code that needs to be written in the native language of the machine–if only to bring up the higher-level language execution and for drivers and kernel code. But with inexpensive (and mostly 32-bit ARM-based) microcontrollers increasingly at the heart of our systems there’s no sense wasting time coding the application code in assembly.

We can attribute about 7 percentage points of the growth in use of C to the reduction in use of assembly during these years. This trend has helped use of C grow to about 60%.

But what’s also been happening in this time is that C++ has failed to capitalize on earlier gains. The peak year for C++ use was apparently 2006, when it had 33% share. Use of C++ as the primary language has since fallen and thus added about 10 percentage points to use of C.

I didn’t include Java in the graph, but it’s use has been less common than assembly in every survey year, with high points of 3% and now down around 1% the last three years. And no other language has emerged to maintain greater than 1% share.

What I make of all of this is that C remains the most cost-effective way to write embedded software. In hindsight, object-oriented languages have been tried but failed to establish their value to most programmers. C++ is a player but looks unlikely to ever eclipse its namesake.

What do you see in the data?