Cadence announced during their recent quarterly earnings announcement and call that we are acquiring approximately 16% ownership in Green Hills Software for about $150M. Lip-Bu Tan, Cadence's CEO, joined their board of directors.

Talking of Green Hills always reminds me of when I was a kid. In our school assembly, we always sang a hymn (unlike the US, Britain has an official religion). One of them was:

There is a green hill far away, Without a city wall

I always wondered why you would expect a green hill to have a city wall. It's an old use of "without" to mean "outside". It has died out in England, but when I did my post-graduate work in Edinburgh, I discovered that the Scottish say "outwith" still.

Vast, Virtutech, and RTOSes

As it happens, between my two tours of duty at Cadence I worked for VaST Systems Technology and Virtutech. They were both virtual platform companies, providing software that allowed binary code written for one processor (say an Arm core, or the NEC V850, a processor that you've probably never heard of but is really big in Japanese automotive) to be run on a regular PC, which, of course, has an x86 under the hood. For example, when AMD was creating the 64-bit x86 architecture (during Intel's Itanium foray), Virtutech provided the software that allowed Microsoft to port Windows to the new processor, running the 64-bit binaries on the then-current 32-bit processors. As a result, Windows booted on the first day silicon came back from the fab. This is basically unheard of.

The alternative to using a virtual platform is to use a development board. But that requires the processor to be available in silicon, and even then it is often inadequate since SoCs may have lots of complex peripherals too. People building embedded systems, all had the problem that they wanted to build a chip, and run an RTOS (real-time operating system), and compile the real source code to the real binary, and then be able to debug it, all on their desktop PC. As a result, the embedded operating system companies were major partners of ours at both companies.

The two biggest companies in the space were Wind River (in Alameda...yes, on the island) and Green Hills (in Santa Barbara). The two companies came to have very different strategies. Wind River had historically had a proprietary RTOS called VxWorks and another, pSOS, that resulted from an acquisition. If you had a camera back in the late 1990s it probably ran pSOS. If you happened to have a Mars Pathfinder, it ran VxWorks. But if you happened to be in the military or aerospace, you likely used Green Hills' RTOS called Integrity. That was when Wind River jumped on the open source trend, with the goal to be "the Red Hat of embedded." They switched to Eclipse as their development environment, and various flavors of Linux as their RTOS. They were eventually acquired by Intel, and then went on to acquire Virtutech, after I'd left. Intel divested that division last year.

Green Hills and Integrity

Green Hills took the opposite approach and doubled down on Integrity, investing a lot in certification. Integrity-178B is certified to NIST's EAL6+, the highest common criteria security level ever for any operating system. If you work in aerospace, the 178B number will immediately mean something to you. DO-178B is (or was, since DO-178C replaced it in 2012) the guideline Software Considerations in Airborne Systems and Equipment Certification. It is the standard for developing avionics software, despite officially being merely a guideline, since it is the starting point that the FAA uses to certify aircraft. I don't want to overstate the comparison, but it is the aerospace equivalent of ISO 26262 automotive functional safety standard. It was jointly developed with Europe, but there it has a different number, ED-12B.

At Virtutech we did some work in aerospace with Green Hills. It turned out that for our virtual platform software our certification for DO-178B was minimal. We only produced verification software, so we could miss catching an error that was already there, but never introduce a new error.

Green Hills has different variants of Integrity, and also a system for tiny devices called Micro Velocity, which they insist on writing µ-velOSity, a product name tic that I dearly hope Cadence doesn't decide to adopt. They also have compilers, middleware, and an IDE (integrated development environment) called MULTI. They have leadership in embedded software, requiring safety and security. In this networked era, almost all software requires safety and security to be designed in, although historically it has often been treated as an afterthought. In just the last week we have heard of radio-controlled construction site cranes, and networked supermarket freezers. It is not just the "obvious" applications like planes or medical devices that require robust safety and security.

Green Hills' customer base is a list of marquee names: Boeing, Lockheed Martin, Ford, Toyota, and, a surprising entrant in this list, Nintendo (Wii). Plus lots more. Green Hills is privately held, and is profitable.

System Design Enablement

Partnering with Green Hills and moving into the embedded software and security market is a natural step moving up the system stack. I talked above about virtual platforms, but the challenge was always developing models for the chips in a fast enough timeframe. It has turned out that the solution to this is emulation and FPGA prototyping, products that Cadence already has. Palladium Z1 for emulation, and Protium S1 for FPGA prototyping. Although these products both model the hardware, often the reason is not so much to validate the hardware, but to provide a foundation to allow the software to be developed and debugged. For a more in-depth look at this, see my post Emulation: the Key to Virtual Platforms.

Addressing safety and security requires a multi-level approach involving both hardware and software. Cadence expects to collaborate on providing integrated solutions to enable the development of highly-secure embedded systems. For a more detailed take on SDE and software, see my post Software Isn't the S in SDE.

Learn More

Here is the press release. Green Hill's website (ghs.com). That's pretty much all there is for now. I will cover future announcements on Breakfast Bytes, so watch this space.

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