There's no need to be confused
The data you are planning to store and access passes through a lot of different things in those processes: storage devices, storage device controllers, CPU, RAM, network interface cards, network switches, your computer, probably lots of other things too. Every one of those things has the potential to corrupt data as it passes through or is stored/retrieved.
Your first post in this thread asked about avoiding corruption in 'storage and backups', so the replies have been focused on those aspects.