h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Not only in the pda and smartphone markets, but in the embedded area generally.

Because it supports so many embedded processors, and is free, it slashes the development cost of embeded software.

so it turns up in set top boxes, personal video recorders like the tivo, pda's, mobile phones, car hi-fi's, in-car entertainmetn systems (like movie players and mp3 players).

it even is used in some of the embedded equipment that is used on the space shuttle and space station. (in fact you seldom find ms windows systems in use there since an NT laptop crashed and they had to wast most of a day reinstalling via a radio link).

At the other end of the market, the altix range of supercomputer clustering solutions only has linux as it's operating system because of the money it saved them in development.

Embedded linux still seems to have a small share of the overall market. Symbian is one of the most commonly installed OS in "smart phones". PalmOS runs the Palm series of PDAs. Most products containing the TI TMS320 series of Digital Signal Processors, which are used extensively in video and audio equipment, use the DSP/BIOS kernel that ships with TI's Code Composer Studio, which is royalty free. One of the largest installed bases of operating systems is OSEK which is a semi-open system developed for automotive engine controllers. Some other examples of embedded and real-time operating systems are QNX/Neutrino and Wind River VxWorks. If you want a really reliable operating system, you might want one developed to the RTCA/DO-178B level A standard for safety critical applications such as CsLEOS, Green Hills Integrity, or Lynx 178 (LynuxOS) which may have a little bit of unix surviving in it, although I'm unaware of any safety critical (level A) product using lynx. Blue Cat Linux is non-deterministic embedded linix commercial offering which also has a real time counterpart. Lots of companies simply write their own OS kernel for their products; it's not rocket science any more.

Specifically with the current set of smartphones, you might be right.

however there is a fundamental problem with the current development model which means that it won't remain that way.

The developers have seen what happens when you let microsoft grab control of an industry, and so are determined that they will not get control of the mobile phone market. this means that they will never be a monopoly player in that industry, and thus "pocketpc" smartphones are largely a novelty, especialy as they only really connect well to a microsoft windows desktop for data syncronisation.

This leaves three serious players in the mobile phone / pda market.

on the one hand, you have palmOS who have most of the remaining market share of the pda market. Unfortunately they have had problems expanding their os to provide phone functionality, and thus it is not currently an option for smartphones.

In the phone market, you have symbian which has most of the remaining market share in the mobile phone market, but abandoned the pda market when they stopped making the psion organisers, and thus have no significant prosence in the pda market.

The only other serious player in this market of pda / phone combinations which I have seen is linux, and there have been a number of "proof of concept" smartphones based around the embedded version.

As the development and licensing costs are fairly cheap, it will undoubtedly grab a reasonable share of the market as it has in just about every other market it has seriously attempted to enter.

Most of the other systems you refer to are either niche markets, or are "hard real time" applications, which linux currently doesn't attempt to enter, and I am not currently aware of any open source projects which can handle the sort of real time response periods needed for engine management systems, but then most proprietary systems can't handle it either.

I have absolutely no doubt that eventually there will be open source safety critical systems, and I am sure that some of the nasa linux based jobs might fall into that category, but of course you usually don't hear about them.

As to companies "rolling their own kernel", IBM have already publically stated that they could not afford to create from scratch a system with the quality found in linux. If a company their size can't afford to do it, what makes you so sure that new players in the embedded market are going to be any more able to do so?

I use netBSD from time to time - who needs a GUI

if you have an older any pcs like me you can go to www.damnsmalllinux.org and download the 50 mb live os!
ive successfully run it on a 586 laptop with 24 mb ram.
nothing like squeezing every ounce of usefullnes out of an old computer.

Since I participated in this thread, I've become involved in some more embedded SW development projects, and what has struck me is the extent to which open source tools, particularly the gnu compilers and debuggers, are being used in a cross-platform environment, to do embedded development. Many companies (like my current employer) which have standardized on Windows desktops are using tools such as Cygwin to provide a linux environment for open source tools to run in, rather than buying embedded development tools. I've also seen the case where large companies which have Unix based tools have "ported" them to Windows using a X-window environment simulator - Mentor Graphics for example uses the mks software package in the Windows version of their EDA tools, which were designed for Solaris and HP-UX (originally designed for Apollo / Domain).

well said. actually you make a good point.

open source development tools are increasingly being used for cross platform development work, and because of their uubiquitousness in certain operating systems make porting not easy, but not difficult either.

Even the stuff I write to run on windows ME is done using djgpp, which is a dos compatable version of gcc and lots of the gnu tools.

I am by no means alone in this.

in fact, recent statistics suggest that there are now more people developing using a unix base and the gnu tools (or similar) than those who are using platform specific tools.

There are 3 different sets ofcross platform tools that I can thing of without really trying for unix, all open source (although one of them charges you if you sell the software using it on windows).

the fact is that software developers are technical people, and technical people prefer the advantages of unix once they understand it.