Memory Subsystem in Microcomputer Systems

In microcomputer systems, the memory subsystem plays a crucial role in storing and retrieving data. When a large memory is required, the memory subsystem is generally designed using dynamic random access memory (DRAM). Let's understand why DRAM is preferred over other options.

1. Static RAM (SRAM)
Static RAM is a type of memory that uses flip-flops to store each bit of data. It is faster and more reliable than dynamic RAM, but it is also more expensive and requires more power. SRAM retains data as long as power is supplied, and it does not need to be refreshed like DRAM. However, SRAM has a lower storage density, which makes it less suitable for large memory requirements.

2. Dynamic RAM (DRAM)
Dynamic RAM is a type of memory that stores each bit of data as a charge in a capacitor within a memory cell. DRAM is cheaper and more compact than SRAM, making it suitable for large memory requirements. However, DRAM needs to be refreshed periodically to prevent the charge from leaking away. This refresh operation consumes additional time and resources, but it allows DRAM to achieve higher storage density.

Advantages of DRAM in Large Memory Systems
- Cost-effective: DRAM is more affordable compared to SRAM, making it a suitable choice for systems that require a large memory capacity.
- Higher storage density: DRAM offers higher storage density, meaning more memory can be packed into a given physical space.
- Compact size: DRAM's smaller form factor allows for more memory to be integrated into microcomputer systems, without significantly increasing the size or weight of the system.
- Suitable for dynamic data: DRAM is well-suited for storing dynamic data that frequently changes, as it allows for quick read and write operations.

Conclusion
When a large memory is required in a microcomputer system, the memory subsystem is generally designed using dynamic RAM (DRAM). DRAM offers cost-effectiveness, higher storage density, compact size, and suitability for dynamic data. While static RAM (SRAM) has its advantages, such as faster access times and reliability, it is less suitable for large memory requirements due to its higher cost and lower storage density.