Java Microprocessors

In the last few years, a new approach for dealing with WCET analysis in Java has emerged. Rather than fight the increasingly unpredictable behavior of virtual machines and superscalar processors, an alternative strategy eliminates them entirely. The approach relies on specialized processors that understand Java bytecode as their native instruction set. Examples include the aJ-100, the Cjip, and the JOP (see Figure 1.4). These Java-specific processors offer several advantages for real-time systems:

These qualities make Java processors an attractive platform for hard real-time systems. Although moving to such a novel and unique architecture may seem drastic, developers of real-time systems have a tradition of adopting new platforms when special needs arise, as evidenced by the popularity of ARM and PowerPC architectures in embedded devices.

Figure 1.4.  The Java Optimized Processor runs on FPGA chips, such as the Altera Cyclone.

Photograph of the Cyclone FPGA