HIMALAYA NONSTOP SERVER

I'm working with a Compaq NonStop Himalaya Server (Tandem System). This server brings a UNIX environment. It conforms to industry standards that define requeriments for open computing systems and portable aplications. This environment also incorporates the POSIX.1 and POSIX.2 standards; its features greatly resemble a UNIX environment. So my question is if I'am available to run a PHP aplication, Can I install this language in my system? Where can I get the PHP product? Which product or tool can I use to replace PHP? Thank you , very much for your support. Regards Claudio