Distributed Systems

Practical distributed applications are deployed into varied environments and execute on a variety of different machines linked together over a variety of communication infrastructure. The physical machines themselves can differ in the number and speed of processors, the availability of random access and stable storage, and more. The communication infrastructure can differ in the available levels of latency, throughput, and reliability. Because of these differences, it is more practical to look at distributed algorithms from a higher-level perspective so that they are applicable to a wide range of environments....

When building and running a system deployed as a monolith, we are able to make a certain set of assumptions about the behaviour of the overall application. One of the biggest assumptions we make is that the memory space for the application all resides on the same machine. With this model, function and library calls can assume that their view of the data structures for the application are accurate, and that you can retrieve or mutate that data immediately and deterministically (leaving the thornier issues of multi-threaded applications aside for a minute)....