  Kahn Process Networks (KPNs) are a deterministic Model of Computation (MoC)
for distributed systems. KPNs supports non-blocking writes and blocking reads,
with the consequent assumption of unbounded buffers between processes. Variants
such as Finite FIFO Platforms (FFP) have been developed, which enforce
boundedness. One issue with existing models is that they mix process
synchronisation with process execution. In this paper we address how these two
facets may be decoupled.
  This paper explores a recent alternative called bittide, which decouples the
execution of a process from the control needed for process synchronisation, and
thus preserves determinism and boundedness while ensuring pipelined execution
for better throughput. Our intuition is that such an approach could leverage
not only determinism and buffer boundedness but may potentially offer better
overall throughput.
  To understand the behavior of these systems we define a formal model -- a
deterministic MoC called Logical Synchrony Networks (LSNs). LSNs describes a
network of processes modelled as a graph, with edges representing invariant
logical delays between a producer process and the corresponding consumer
process. We show that this abstraction is satisfied by KPNs. Subsequently, we
show that both FFPs and bittide faithfully implement this abstraction. Thus, we
show for the first time that FFPs and bittide offer two alternative ways of
implementing deterministic distributed systems with the latter being more
performant.
