The surroundings of the recently accessed block is called as locality of reference.

The term "locality of reference" refers to the tendency of a computer program to access data or instructions that are close to each other in memory. This concept is based on the observation that programs often access a small subset of their memory at any given time, rather than accessing random locations. By taking advantage of this locality, computer systems can optimize memory access and improve performance.

Types of Locality of Reference:
There are three main types of locality of reference:

1. Temporal Locality:
Temporal locality refers to the tendency of a program to access the same memory location multiple times within a short period of time. This occurs when a program repeatedly references the same variables, arrays, or instructions. By keeping frequently accessed data or instructions in a cache or registers, the system can reduce the time and energy required to fetch them from main memory.

2. Spatial Locality:
Spatial locality refers to the tendency of a program to access data or instructions that are located close to each other in memory. This occurs when a program accesses consecutive elements of an array or loops through a series of instructions. By prefetching or caching consecutive memory locations, the system can reduce the number of memory access operations and improve overall performance.

3. Sequential Locality:
Sequential locality refers to the tendency of a program to access data or instructions in a sequential manner. This occurs when a program accesses memory locations in a predictable order, such as when iterating through a linked list or traversing a tree. By prefetching or buffering the next expected memory location, the system can reduce the latency of memory access and improve efficiency.

Significance of Locality of Reference:
Understanding and exploiting the concept of locality of reference is crucial for designing efficient computer systems. By optimizing memory access patterns based on the different types of locality, system designers can improve cache performance, reduce memory latency, and enhance overall system efficiency. Techniques such as caching, prefetching, and branch prediction are employed to exploit the concept of locality and minimize the impact of memory access delays.