A Platform Support Module (PSM) is a piece of software that defines specific architecture features of a hardware platform. A PSM is implemented using the Platform Support Kit (PSK), which includes full documentation:
PSM is a versioned interface, so all PSMs must be installed with a Master(DSP/4dsp) file that includes a line such as the following:
$interface psm 2PSMs do not use any functions, entry points, or routines that are used by other interfaced versions, so their Master files do not include any other $interface lines.
PSM version support
|O/S release||Supported versions|
|SCO SVR5 2.X||psm: 1|
|SVR5, all versions||psm: 2|
See ``DDI interface versioning''.
At one time, there was enough commonality among the system architectures of all platforms that used the Intel 386, 486, and Pentium microprocessors that the base operating system could accommodate any platform-specific code required for supported platforms. The varied system architectures being used for Intel-based multiprocessor platforms, however, makes it impossible to efficiently and effectively provide a single kernel binary that supports all platforms. Instead, the PSM interface specification (PSMIS) has been defined to enable platform developers to create separate modules that define hardware details of their architecture such as interrupt distribution, I/O symmetry, and processor control.
Note that the PSMIS is identical to a Hardware Abstraction Level (HAL). The PSMIS abstracts the architectural variations that exist among Intel-based multiprocessor systems.