A computer system is made up of several components including input and output devices, a central processing unit (CPU), storage devices and memory. All these components work together as a single unit to produce the desired result. A computer system can be of various sizes and shapes. It can range from a high-end server to a laptop, personal desktop, smartphone, or a tablet. A system model is a tool that predicts the performance of a system under changing circumstances. System modeling refers to a process that involves developing abstract models of a system, wherein each model presents a different view of that system. It involves representing a system using some kind of graphical notation, which can be used by analysts to understand the system's functionality. The process of observing systems for troubleshooting or development purposes is known as systems analysis. Probabilistic modeling methods are applied in the study of computer systems. Models may be analyzed using queuing theory models or stochastic processes. This book aims to shed light on the modeling and analysis of computer systems. It will serve as a valuable source of reference for graduate and postgraduate students.