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| Requirements |
| Hardware for a DBMS |
Conventional DBMS hardware consists of secondary storage devices, usually hard disks, on which the database physically resides, together with the associated I/O devices, device controllers, I/O channels and so forth. Databases run on a range of machines, from micro-computers to large mainframes.
Other hardware issues for a DBMS includes database machines, which is hardware designed specifically to support a database system. |
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| Operating Systems. |
When a database management system runs on a computer it runs as yet another application program as far as the machine is concerned. In between the DBMS and the hardware of the machine lies the host machine's operating system like UNIX or VAX/VMS, file manager and disk manager which deal with the file structure of the operating system and the page structure of the machine.
In order to allow a general purpose machine to be used for other applications besides DBMS functions, the DBMS software uses the file manager and data manager of the underlying operating system, though sometimes the DBMS may use its own file manager. In a software backend database machine the operating system is not general purpose. |
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| Software for a DBMS. |
| Between the physical storage of data on hardware and the users, lies the database management system which handles ALL the interaction between the two. This means the DBMS effectively shields users from hardware and operating system level details and provides users with a higher level view of the database. |
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| Balancing enterprise requirements |
| Knowing the requirements of an enterprise (as opposed to the requirements of any individual user) the DBA can structure the system to provide an overall service that is "best for the enterprise". Hence conflicting requirements between users or application programmers can be balanced. |
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