What is the difference between isolated I/O and memory mapped I/O ? Explain the advantages and disadvantages of each.

Difference between isolated I/O and memory mapped I/O :

Feature	Isolated I/O	Memory Mapped I/O
Memory Space	Uses separate memory space	Uses memory from the main memory
Supported Instructions	Limited to IN, OUT, INS, OUTS	Any instruction referencing memory can be used
Addresses	Addresses for I/O devices are called ports	I/O devices are treated as memory locations
Bus	Efficient due to separate bus	Inefficient due to single bus for data and addressing
Size	Comparatively larger	Smaller
Internal Logic	Uses complex internal logic	Common internal logic for memory and I/O devices
Speed	Slower operations	Faster operations

Advantages of Isolated I/O:

1. Efficient I/O operations due to a separate bus.
2. Addresses for I/O devices are distinct, which can simplify memory management.
3. Provides a larger memory space for I/O operations.
4. May be easier to implement for certain types of devices due to the simplicity of addressing.

Disadvantages of Isolated I/O:

1. Limited instructions available, which may restrict flexibility.
2. Uses complex internal logic, which can increase hardware complexity and cost.
3. Slower operations compared to memory-mapped I/O.

Advantages of Memory Mapped I/O:

1. Any instruction referencing memory can be used for I/O operations, providing greater flexibility.
2. Faster operations due to the use of a single bus for data and addressing.
3. Smaller in size compared to isolated I/O, which can be advantageous for systems with limited physical space.

Disadvantages of Memory Mapped I/O:

1. Inefficient use of memory due to sharing it with I/O devices.
2. Common internal logic for memory and I/O devices might increase complexity.
3. Can be more challenging to manage, especially in systems with a large number of I/O devices.