Alsys Ada will generate an erroneous error message under AIX 1.2.1 during the compile step. The message will say that the compiler is running out of stack space (the format of the error and its exact wording will vary depending on the site where you initiate the compile). You should ignore this message. This problem has been reported to Alsys. A line must be added to your .adarc file to prevent an illegal instruction when executing Ada programs. This line may be added by running "ulib csc ada_install" or by editing the .adarc file and adding the following line at the end of the file: default.bind modules = /lib/crtn.o