Abstract A distributed system is composed of multiple objects interconnected by communication networks. Each object is an abstract data type.
Users write transactions to manipulate distributed objects in a nested fashion.
Transactions are composed of operations and also atomic units of work for users. Each operation can call operations on another objects. This means that op1 can be executed in parallel. In this sense, nested transactions can be executed in parallel in the distributed systems. In this paper, we would like to discuss deadlock problems occurred when transactions are executed in parallel.