Compiler design model question paper

In computer science, a consistency model specifies a contract between the programmer and a system, wherein the system guarantees that if the programmer follows the rules for operations on memory, memory will be consistent and the results of reading, writing, or updating memory will be predictable.
Consistency models are used in distributed systems like distributed shared memory systems or distributed data stores.
Consistency is different from coherence, which occurs in systems that are cached or cache-less, and is consistency of data with respect to all processors.
Coherence deals with maintaining a global order in which writes to a single location or single variable are seen by all processors.
Consistency deals with the ordering of operations to multiple locations with respect to all processors.