Since OpenVMS Alpha Version 7.2, it has been possible to runa single-instance Galaxy on any Alpha platform except for the ES45. Thiscapability allows early adopters to evaluate OpenVMS Galaxy features and,most important, to develop and test Galaxy-aware applications withoutincurring the expense of setting up a full-scale Galaxy computingenvironment on a system capable of running multiple instances of OpenVMS(for example, an AlphaServer 8400).
A single-instance Galaxy running on an Alpha system is notan emulator. It is OpenVMS Galaxy code with Galaxy interfaces andunderlying operating system functions. All Galaxy APIs are presentin a single-instance Galaxy (for example, resource management, sharedmemory access, event notification, locking for synchronization,and shared memory for global sections).
Any application that is run on a single-instance Galaxy exercisesthe identical operating system code on a multiple-instance Galaxysystem. This is accomplished by creating the configuration file SYS$SYSTEM:GLX$GCT.BIN,which OpenVMS reads into memory. On a Galaxy platform (for example,an AlphaServer 8400), the console places configuration data in memoryfor OpenVMS to use. Once the configuration data is in memory, regardlessof its origin, OpenVMS boots as a Galaxy instance.
HP OpenVMS Alpha Partitioning and Galaxy Guide
