Cullinet Software Inc, Westwood, Massachusetts yesterday announced that it has extended its commitment to open architecture by adopting the guidelines for application-software portability set by the UK-based X/Open Co Ltd Portability Guide. The announcement extends Cullinet’s commitment to Unix, initiated when the company agreed a joint development effort with Nixdorf late last year. The X/Open standards are intended to foster portability of applications at the source-code level and it defines a Common Applications Environment.