File Mapping

The sun4_Solaris and alpha_OSF1 implementations of HDS currently provide a choice between the use of file mapping to perform I/O operations on primitive objects and the use of direct read/write operations. This is selectable via the `MAP' tuning parameter (see §). The default is to use file mapping on both systems.

Only read/write operations will be supported on other systems, regardless of the setting of the `MAP' tuning parameter.