Thomas,
The OSI model is a domain specific set of abstractions tailored to networking. ROC offers an abstraction for general purpose computing.
Specifically with regards to the terms "physical" and "logical" levels in ROC we are making a distinction between code where references to variables, objects and methods must be resolved to memory locations (physical level binding) and subsequently do not change and ROC where the binding between an identifier and an endpoint is made for each request and is then forgotten.
The distinction between a physical level and a logical abstraction depends on the context of the discussion as one could say that virtual memory in a modern microprocessor is a logical level residing on top of a physical reality of the hardware addressing model. For the discussion about ROC and traditional programming languages this point of distinction can be seen when one looks at binding, which we explored in the first article in this series:
https://www.theserverside.com/tt/articles/article.tss?l=ARESTfulCorePart1
I hope this answers your question.
-- Randy