A colleague of mine worked in the automotive industry. he was always full of tales about the Detroit boys and their ways. Here is one of his cautionary tale. Keep in mind that at the time, Detroit was into making “platforms” which would be used for many years to come. A typical development cycle, from specification to production, would run anywhere from 3 to 5 years.
The group responsible for the transmission controller was migrating from the venerable 68360 to the (then) new PowerPC 555 processor. The ‘360 code was a mixture of Assembler and C code. This code did its job and everyone was pleased with what it was doing, but it had become your usual nightmare of patches after patches, with no owner, and the original designers long since gone on to bigger and better things. No one understood how the code worked, and the porting attempts to the PPC555 were met with mixed success. When a transmission goes from 50MPH directly to reverse, engineers tend to duck for cover…

As the immutable deadline approached, everyone was starting to panic. Their solution was clever, but oh so frightening… They created a virtual 68360 processor for the PPC555. This virtual processor understood the 68360 object code, so they could simply use the same binary code that had been used for years. With the added horsepower of the 555, the virtual 360 performed faster than the real processor.
I don’t know which scares me the most…a virtual processor running a transmission, or a transmission controller so complex that creating a virtual processor is simpler than a re-implementation?