Describe the basic concepts of CPU scheduling. What criteria are used to evaluate scheduling algorithms, and why are these criteria important in the context of operating systems?

CPU scheduling is a process which allows one process to use the CPU while the execution of another process is on hold(in waiting state) due to unavailability of any resource like I/O etc, thereby making full use of CPU. The aim of CPU scheduling is to make the system efficient, fast and fair.

Whenever the CPU becomes idle, the operating system must select one of the processes in the ready queue to be executed. The selection process is carried out by the short-term scheduler (or CPU scheduler). The scheduler selects from among the processes in memory that are ready to execute, and allocates the CPU to one of them.

There are several different CPU scheduling algorithms used nowadays within an operating system. Each algorithm has its own advantages and disadvantages, and is evaluated based on certain criteria:

1. CPU Utilization: To keep the CPU as busy as possible.
2. Throughput: Number of processes that complete their execution per time unit.
3. Turnaround Time: Amount of time to execute a particular process.
4. Waiting Time: Amount of time a process has been waiting in the ready queue.
5. Response Time: Amount of time it takes from when a request was submitted until the first response is produced.

These criteria are important in the context of operating systems because they directly impact the system's performance and efficiency. For example, high CPU utilization and throughput mean that the system can process more tasks in a given amount of time. On the other hand, low turnaround time, waiting time, and response time mean that individual tasks are completed quickly, which is beneficial for the user. Therefore, the choice of a scheduling algorithm and its implementation can greatly affect the performance of the system and the user's experience.