i don't have enough knowledge about storage systems but have to tell my audiences about how storage works in organization data centers.

For this purpose to keep things simple, first i want to show them a layer model then from top to bottom and then i want to explore all these layers.

What i mean by layered model in storage architecture?

i want to start my presentation something like that, first layer can be applications, application request a data from storage and then ... ... (the topics i want to cover are file sytems, metadata,the physical implementation of storage (das, nas etc.) ... the request comes to the storage device and storage device (depends on the technology) goes through the disk and disk send back the data using iscsi protol, we can say that the iscsi protocol managing the path between... ...

if you help me explain these steps layer by layer by examples and key technologies to be defined, really appreciate it.

thanks.