fab OpenVMS usage:fab type: unspecified access: modify mechanism: by reference File access block (FAB) used with LIB$FILE_SCAN. The optional fab argument is the address of the FAB that contains the address and length of the file specification. context OpenVMS usage:context type: longword (unsigned) access: modify mechanism: by reference Temporary default context used in LIB$FILE_SCAN. The optional context argument is the address of a longword containing this temporary default context.