@proc_da Which AML version? There are different types of headers - it's in the docu.    For auto-generated headers: There are SAS AML Solution macros which generate a SAS data step program based on the header registration and scenarios registered against the header. These macros also read the job calendar and only pick up the scenarios to be run for the current date.   The generated code in a nutshell looks like:   data alert; /** header section +*/ set prep_file; array .... /** scenario section **/ /* scenario 1 */ if <some condition> then output; /* scenario 22 */ if <some other condition> then output; run; I haven't worked with the high performance version (VA) but it's supposed to work similarly on a conceptual level.     ... View more

Metadata Server is self-explaining. Compute Server hosts the Base SAS components, workspace, stored process, OLAP servers, and the spawner to start/connect to them Mid-Tier hosts the web and web application servers (apache & tomcat) and therefore all web applications ... View more

The source to staging transition will be of simple select and simple functions like cast, and case when statements using joins to join the two or more source table and inserting into the staging table.   Its better to ask the ETL Team to share the scripts for better understanding. ... View more