Secondary storage devices

Modern computers employ a hierarchy of storage devices which may be broadly divided into two categories: ‘primary’ and ‘secondary’ systems.

What is secondary storage? The bulk of data can’t be stored in the main memory as this memory is costly and naturally some other cheaper memory devices are required. These cheaper memory devices, called Secondary Storage Devices can store bulk of data at very less cost.

Devices such as flash memory, the hard disk, floppy disk, and writable optical disk, provide with examples of secondary storage devices. These offer larger storage capacity than primary storage devices, but operate more slowly. Flash RAM, sometimes embedded within solid-sate drives, provides the fastest access at the highest cost. Optical discs offer the slowest but cheapest storage method.

The secondary stored devices allow permanent storage of data and instructions. The data stored on a secondary storage device can be accessed, depending upon how it its stored on the device.

The benefits of secondary storage including:
*Non-Volatility
*Large capacity
*Reliable
*Convenience
*Low cost
*Re-usability
*Portability
Secondary storage devices

In-memory database

In-memory databases do not use any file to store any kind of information, the databases and their logs are stored entirely in the main memory. So, the database operations are superfast. When the application closes an in-memory database, the database is eliminated from the main memory.

In-memory database management systems have the potential to reduce the execution time of complex operational analytical queries to the order of seconds while executing business transaction in parallel.

Since in-memory database utilize the server’s main memory as primary storage location, the size, cost and access speed provided by main memory components are vitally important.

With the help of data compression, today’s standard server systems comprise sufficiently large main memory volumes to accommodate the entire operation data of all companies.

Main memory, as the primary storage location is, nevertheless, becoming increasingly attractive as a result of the decreasing cost/size ratio.

The In-Memory Database (IMDB) technology has proven to have major capabilities for analyzing big enterprise and medical data, e.g., to identify relevant patient data and to protect markets from injecting pharmaceutical counterfeits.
In memory database