Digital UNIX / PALcode Revision Notification

This document addresses a compatibility issue between PALcode revision 1.45 (or greater) and Digital UNIX versions prior to V3.2F on certain Alpha systems. The issue specifically affects applications performing IEEE floating-point operations, potentially leading to console error messages such as "unknown OPDEC from ieee emulation" or "Illegal instruction" faults. Systems with factory-installed software V3.2F or higher, or those with existing patches, are not affected. Customers reinstalling older versions of Digital UNIX may encounter this issue. The document provides two workarounds: applying a specific software patch from Digital Customer Support based on the installed UNIX version or, for systems other than the AlphaStation 255, reverting to a previous version of PALcode.