Soft Watch

Electronics Times, July 17, 2000

You like peas. You like cheese. Well, now it's your favourites all in one: cheesy-peas.

The Linux community can thank The Fast Show for coming up with the latest way of marketing the open-source operating system to embedded systems designers. Hot on the heels of the decision by several of the RTOS companies to offer pSOS migration support for Wind River's recently acquired operating system, members of the Linux and even the Windows NT community have decided to do the same.

To recap, Wind River has decided to merge its VxWorks and pSOS operating systems together, with plans to support a compatibility layer for them in a version known as Cumulus, which should appear by 2002. As seen in the desktop world, when a large player makes plans to move to a new technology base - as with Sun's move to Solaris 2 - it is the perfect opportunity for competitors to tempt dissatisfied customers with their offerings.

Declaring the move early on might look as though Wind River just blew a huge hole through its corporate foot. But the damage is going to be a lot less than if the company dithered while it came up with Cumulus with no clear plan for its customers in the meantime. Overall, the company can expect to lose some customers but not nearly as many as it would if it tried to pretend to continue with two incompatible offerings.

So it did not come as a surprise to see Accelerated Technology and Green Hills announce that they would deliver compatibility libraries for their respective RTOSs.

The reason why a group of Linux suppliers, such as Lineo and Montavista, has moved in on this turf is obvious but less clear cut for the developer. The first batch of would-be pSOS migrators have technology that more or less works like their target. For example, Nucleus is a small-footprint, thread-model RTOS much like pSOS. There are differences and there is one system call in pSOS that is going to be very tricky to emulate cleanly.

The difference between pSOS and something like Linux is huge and not just in terms of memory footprint. Linux is a process-model operating system with radically different behaviour. The one bit of overlap is that Integrated Systems, which Wind River bought last year, had done a lot of work on Posix compatibility for pSOS during the mid-1990s. Linux also has a largely Posix-compliant programming interface. Unfortunately, like Windows NT, it needs yet another RTOS underneath to support real-time applications. The move is not going to be quite as simple as some companies seem to think.

What they have latched onto is the attraction of royalty-free software and that there is a base of companies that might take the opportunity to jump ship from another RTOS such as pSOS. Whether it makes sense to slap the two leading names behind those trends is another matter.