Also, is Savant the same as RFID middleware—and if they are the same, why are they called by different names?
This question is a blast from the past, as I have not heard anyone use the terms "Savant" and "PML" [Product Markup Language] in a long time. Those terms, in fact, go back to the original Auto-ID Center, which developed the first Electronic Product Code (EPC) ultrahigh-frequency (UHF) air-interface protocol, the concepts for what was then called the EPC network, and some of the basic software for turning EPC data into something that could be used by back-end software applications.
The Auto-ID Center envisioned utilizing a form of the extensible markup language (XML) used on the Web to describe products and their characteristics. Soft drinks might have terms associated with that type of beverage, such as "liquid" and "fizzy," as well as other characteristics, including size and the type of container (bottle, can or plastic). PML would also include information that could change over time, such as where a product was located, or what its temperature was.
Savants were intended to be distributed pieces of software that would allow for machine-to-machine (M2M) communication. They would filter data and pass on any relevant information, while ignoring redundant reads (an EPC reader might ping a tag 100 times a second while sitting on a shelf, but there would be no need to know the product was still there—only that it had moved).
After licensing the EPC technology from the Massachusetts Institute of Technology (MIT), where the original Auto-ID Center began, GS1 created EPCglobal and began commercializing the technology. The Auto-ID Center became the Auto-ID Labs, which continues to conduct research to this day, in order to support the development of EPC standards.
When EPCglobal began looking at creating standards not just for the air interface but also for how data would be shared, it created committees made up of technologists from RFID companies, as well as end users. The original concepts of PML and Savants were jettisoned. I have no inside information as to how or why that happened, but I suspect that when it came to implementing these concepts, it became clear that it would be simpler just to create a set of standards that would allow companies to share existing product data, with additional information about location, temperature and so on, than to create an entirely new way of sharing product data. PML gave way to the EPC Information Service (EPCIS), while Savants gave way to commercial middleware.
Strictly speaking, PML is not equal to EPCIS, and Savants are not the same as middleware—but they do perform equivalent functions. I should also note that the term "EPC network" was dropped because some companies thought of it as an America Online-like service owned and operated by EPCglobal—when, in fact, it was always envisioned as a way to share EPC data over the Internet.
—Mark Roberti, Founder and Editor, RFID Journal