Mechanisms for compensation handling and dynamic update are increasingly relevant in the specification of reliable communicating systems. Compensations and updates are intuitively similar: both specify how the behavior of a concurrent system changes at runtime in response to an exceptional event. However, calculi for concurrency with compensations and updates are technically quite different.

We compare calculi for concurrency with compensation handling and dynamic update from the standpoint of their relative expressiveness. We develop two encodings of a process calculus with compensation handling into a calculus of adaptable processes. These encodings differ in the target language considered: the first considers adaptable processes with subjective updates in which, intuitively, a process reconfigures itself; the second considers objective updates in which a process is reconfigured by a process in its context.

Our main discovery is that subjective updates are more efficient than objective ones in encoding primitives for compensation handling: the first encoding requires less computational steps than the second one to mimic a single computation step in the source language of compensable processes. Our encodings satisfy strong correctness criteria; they shed light on the intricate semantics of compensation handling.

补偿处理和动态更新的机制在可靠通信系统的规范中越来越重要。补偿和更新在直观上相似：两者都指定并发系统的行为在运行时如何响应异常事件而改变。但是，与补偿和更新并发的计算在技术上是完全不同的。

从它们相对表达的角度，我们将并发计算与补偿处理和动态更新进行比较。我们使用补偿处理将过程演算的两种编码开发为可适应过程的演算。这些编码在所考虑的目标语言方面有所不同：首先考虑具有主观更新的可适应过程，在此过程中，过程会直观地进行自我配置；第二部分考虑了客观更新，在该更新中，流程由其上下文重新配置。

我们的主要发现是，在进行补偿处理的编码原语中，主观更新比客观更新更为有效：第一种编码比第二种编码需要更少的计算步骤，以模仿可补偿过程的源语言中的单个计算步骤。我们的编码符合严格的正确性标准；他们阐明了补偿处理的复杂语义。