RAM
RAM(random access memory) is the place in a computer where the operating system, application programs, and data in current use are kept so that they can be quickly reached by the computer's processor. RAM is much faster to read from and write to than the other kinds of storage in a computer, the hard disk, floppy disk, and CD-ROM. However, the data in RAM stays there only as long as your computer is running. When you turn the computer off, RAM loses its data. When you turn your computer on again, your operating system and other files are once again loaded into RAM, usually from your hard disk.RAM can be compared to a person's short-term memory and the hard disk to the long-term memory.
Raw data
Raw data is data that has not been processed for use. A distinction is sometimes made between data and information to the effect that information is the end product of data processing. Raw data that has undergone processing is sometimes referred to as cooked data.Although raw data has the potential to become "information," it requires selective extraction, organization, and sometimes analysis and formatting for presentation.
Real time
Real time is a level of computer responsiveness that a user senses as sufficiently immediate or that enables the computer to keep up with some external process (for example, to present visualizations of the weather as it constantly changes). Real-time is an adjective pertaining to computers or processes that operate in real time. Real time describes a human rather than a machine sense of time.
RDBMS
A relational database management system (RDBMS) is a program that lets you create, update, and administer a relational database. Most commercial RDBMS's use the Structured Query Language (SQL) to access the database, although SQL was invented after the development of the relational model and is not necessary for its use.The leading RDBMS products are Oracle, IBM's DB2 and Microsoft's SQL Server.