Introduction:
In computer systems, memory refers to the storage space used to store data and instructions for processing. There are various types of memory, each with its own characteristics and functionality. One important aspect of memory is the need for periodic refreshing. In this context, we will discuss the memory type that requires periodic refreshing - DRAM.

Explanation:
DRAM stands for Dynamic Random Access Memory. It is a type of volatile memory that stores each bit of data in a separate capacitor within an integrated circuit. Unlike SRAM (Static Random Access Memory), which uses flip-flops to store data, DRAM requires periodic refreshing to maintain the stored information.

Reasons for periodic refreshing:
The need for periodic refreshing in DRAM arises due to the nature of the storage mechanism. Here's why:

1. Capacitor leakage: In DRAM, the data is stored as charge in the capacitors. However, over time, the charge leaks away due to the natural properties of the capacitors. This phenomenon is known as capacitor leakage. The charge leakage causes the stored data to degrade and eventually become unreadable. Refreshing the memory periodically helps to replenish the charge in the capacitors, ensuring the data integrity.

2. Row and column access: DRAM uses a matrix of rows and columns to store and retrieve data. When a row is accessed, the data in that row is read and amplified before being sent to the output. However, during this process, the charge in the capacitors representing the accessed row tends to spread to the nearby rows. This phenomenon is known as row leakage. To counteract this, the rows need to be refreshed periodically to maintain the data integrity.

3. Power consumption: DRAM consumes more power compared to SRAM. This is because the capacitors need to be refreshed periodically, which requires additional circuitry and power consumption. However, DRAM is preferred over SRAM in applications where high-density and lower cost are essential factors.

Conclusion:
In conclusion, DRAM is the type of memory that requires periodic refreshing. This is due to the inherent properties of its storage mechanism, such as capacitor leakage and row leakage. Periodic refreshing helps to maintain the data integrity and ensure reliable operation of the memory.