Attention! NS is a client/server software system. The Attention! NS Server, which receives messages from licensed systems running the Attention! NS client software, runs on Windows 2000, Windows 2003 and Windows XP. The Attention! NS client software has been ported to over 15 Operating Systems including NT, 95/98, 2000, 2003, Linux, virtually all UNIX, OpenVMS, OS400 and MVS.