The Installation System frequently uses symbolic variables in data set names, data set prefixes, and job-statement information.
When the Installation System assembles product options, macro processing tries to resolve all symbolic variables in the listing. Most symbolic variables are resolved when the Installation System generates JCL. When necessary, the Installation System doubles the ampersand for all symbolic variables to prevent errors.
Single quotation marks within literal values if the literal is enclosed with delimiting single quotation marks
A period if the literal immediately follows a variable name
The following table illustrates the use of double characters: