IA: Added Support for PAE Mode

With the release of Pentium Pro, Intel introduced a mode called Physical Address Extension (PAE) on its advanced processors. By using PAE, Solaris Intel Platform Edition can address up to 32 Gbytes of physical memory. Individual processes are still limited to a maximum of 3.5 Gbytes of virtual address space.

PAE mode enables the user to run multiple instances of databases and memory-intensive applications, and to support large numbers of online users on a machine.

It is best to use PCI disk controllers that support Dual Address Cycle (DAC) in your machine because they can transfer data to and from any physical location. Other cards are limited to 4 Gbytes of physical memory, and as a result performance may slow down because the system needs to copy additional memory to transfer data.

Some device drivers are not yet able to take advantage of PAE mode. Sun has tested PCI device drivers written by Sun on IA based machines with more than 4 Gbytes of memory. Sun's OEM partners intend to test their machines with devices they supply on IA based machines with more than 4 Gbytes of memory. In some cases however, if you add a third-party device driver to your system, it may become unstable, and panics and data corruption may result. If your system becomes unstable and you need that driver, you must disable PAE mode support. For more information, see the Solaris 8 (Intel Platform Edition) Device Configuration Guide.

This feature was first available in the Solaris 7 3/99 release.