1. You can run the exact same package simultaneously. What you can't do is execute a job while it's currently running. I can set up a job to run package anand_vanam.dtsx. I can set up a second job to run the same package, and they'll run simultaneously.
This situation seems clear to me. But what if I want to run the same package from within the same job but would be called from another thread. For example, I want to create a package that produces a TSQL recordset based on a variable passed in. There would be multiple procedures in the parent package that would call child packages, several of which would have this one package and each one passing in a different variable. Would this work?
I know I can test it, and if no one is sure of the answer I will soon enough, but I'm trying to think my way through a new ETL process at the moment. I read something on modularity in SSIS the other day and it got me thinking about this possibility.