The Oracle Database (commonly referred to as Oracle RDBMS or simply as Oracle) is an object-relational database management system (ORDBMS) produced and marketed by Oracle Corporation.
Larry Ellison and his friends and former co-workers Bob Miner and Ed Oates started the consultancy Software Development Laboratories (SDL) in 1977. SDL developed the original version of the Oracle software. The name Oracle comes from the code-name of a CIA-funded project Ellison had worked on while previously employed by Ampex.
Disk files primarily consist of the following types:
- Data and index files
- Redo log files consisting of all changes to the database, used to recover from an instance failure
- Undo files used for recovery, rollbacks, and read consistency
- Archive log files
- Temporary files
- Control files containing information on data files
At the physical level, data files comprise one or more data blocks, where the block size can vary between data files.
Data files can occupy pre-allocated space in the file system of a computer server, utilize raw disk directly, or exist within ASM logical volumes.
