A stock market, equity market or share market is the aggregation of buyers and sellers (a loose network of economic transactions, not a physical facility or discrete entity) of stocks (also called shares), which represent ownership claims on businesses; these may include securities listed on a public stock exchange as well as those only traded ...
Redundancy is a system design in which a component is duplicated so if it fails there will be a backup. Redundancy has a negative connotation when the duplication is unnecessary or is simply the result of poor planning.
What is RAID? A Redundant Array of Independent Disks, or RAID, is a way of storing the same data across multiple hard drives. Almost all have redundancy to offer some data protection, while RAID 0 is built purely for speed. NOTE: redundancy is NOT a form of backup! There are many ways to use RAID and there are several different types of array.