Clock synchronization in distributed multicomputer systems. Part I

The study substantiates the necessity of clock synchronization in distributed multicomputer systems. The basic definitions related to the concept of clock synchronization are given, and methods of clock synchronization are classified. Increasing the lifecycle of failure- and fault-tolerant distributed multicomputer systems for critical application is one of the most urgent problems at the current level of technology development. This is especially true for unattended distributed multicomputer systems for space applications. The development of such systems should begin with the construction of models of faults and self-controlled degradation, ensuring, firstly, their failure and fault tolerance and, secondly, maximum survivability, which is possible only if there are means of clock synchronization in such systems. All activities associated with ensuring the synchronization of any distributed multicomputer systems begin with the concept of synchronization of on-board functions, which is based on the generation of on-board time and includes the synchronization of on-board software and equipment that requires time synchronization or information about the course of time. The main elements of this concept are the processor clock module, the onboard software clock, the atomic navigation clock. The first part of the work gives basic definitions, and considers methods and algorithms related to the clock synchronization process. The second part is devoted to synchronization in systems with Byzantine faults and in multi-cluster and multi-complex, i.e. multitask, systems. The modern technologies providing the synchronization process in such systems are considered.