TABLE OF CONTENTS Operating systems (OS) are the software that connects the database processing code to the hardware. We assume a working knowledge of operating systems, so little will be described here about what operating systems are and how OS kernels are architected. However, the interesting question for database designers is generally which operating system to use for their database application. The answer to this question often depends as much on history as technology since a company with a large deployment of several applications on a particular operating system may be unwilling to introduce a radically different operating system for a new application. There are good reasons for the hesitancy: the people who administer the systems and databases on the operating system that is heavily used will have less skill on the proposed operating systems, which will introduce short-term expense in skills development and administration costs for the new system. As well, there is risk, legitimate risk of the unknown. However, barring these uncertainties, there are reasons to choose one operating system over another.
The dominant operating systems used in the database market today include Windows, AIX, HP UNIX, Solaris, and LINUX. All of these operating systems have transitioned to support 64-bit processing in recent years. 64-bit addressability is hugely important for database systems, since 32-bit addressability limits the address space of a database to under 4 GB of real memory (usually closer to 2 GB). The larger addressabil-ity of 64-bit systems is massively important for data-intensive...
