Introduction:
The computer cluster architecture emerged as a result of distributed systems.

Explanation:
Computer clusters are a type of distributed system where multiple computers work together as a single system to provide higher availability, reliability, and performance. This architecture allows tasks to be divided among the cluster nodes, enabling parallel processing and reducing the load on individual machines.

ISAs, Workstations, and Supercomputers:
- ISA (Instruction Set Architecture) defines the capabilities and functionalities of a computer's hardware. While ISAs play a role in defining how programs are executed, they are not directly responsible for the emergence of computer cluster architecture.
- Workstations are individual computers used for personal or professional tasks. While workstations can be part of a cluster, they are not the primary reason for the development of cluster architecture.
- Supercomputers are high-performance computing systems designed for complex computations. While supercomputers can be clustered together for even greater processing power, the concept of distributed computing is what led to the creation of computer cluster architecture.

Cluster Architecture:
- In a cluster architecture, multiple computers are interconnected to work together seamlessly.
- Each node in the cluster typically runs its own operating system and applications, but they cooperate with each other to achieve common goals.
- Tasks can be distributed among the nodes for parallel processing, leading to faster completion times and improved performance.
- Cluster architecture also provides redundancy and fault tolerance, as tasks can be rerouted to functioning nodes in case of failures.

Conclusion:
The emergence of computer cluster architecture was a result of the need for distributed systems that could handle complex tasks efficiently by utilizing the resources of multiple interconnected computers. This architecture has become popular in various fields, including scientific research, data analysis, and high-performance computing.