Classification Based on Storage Medium
Learn about DBMS classification based on storage mediums and how to distinguish between in-memory and disk-based databases.
Storage system
There are multiple storage options available, which differ in speed, cost, and accessibility.
Primary storage holds the currently running instructions and data on the motherboard. Hence, access to the primary storage is always faster. However, primary storage is volatile and can lose its contents after system restarts. Also, storage size is limited and expensive. Primary storage includes the main memory and cache as part of its hardware.
Secondary storage devices (e.g. magnetic disks) are nonvolatile devices outside the CPU that hold data and programs for longer periods of time. The data stored on secondary devices persists on system restarts. Secondary devices are economical and can store large amounts of data, but the access patterns are comparatively slower than the primary storage. These are also called online storage.
Tertiary storage devices (e.g. tapes and optical disks) are nonvolatile devices that can hold large amounts of data outside to the computer system. They are also ...