A few general questions about properties and how two apps would run

Regarding properties:

If I store values in a property does that information persist? Does the last value it was assigned survive after a restart of the Mac or a power loss? I understand how to use the global and local variables and when, but properties SEEM to be a different animal and I can’t quite wrap my head around why. Is there any good reason to use them?

Regarding apple script:

Lets say I have an apple script .app running whose function is to wait for files and folders to be uploaded via FTP to my system and then test them to see if they meet certain criteria before adding them to one queue or another for further processing (call it A.app). Then lets say that I have another apple script .app running whose function is to pull those files and folders from the queues and act on them appropriately (call it B.app). Now each of these apps also call on several apple script .scpt files to do various things according to their specialties in the course of processing either the files and folders (A.app) or processing the queues (B.app)

Not knowing a lot about how Apple Script works the question I have is this - will the two applications process their work simultaneously or concurrently? That is to say will A.app have to wait until B.app is finished before it continues or vice versa? If they can process in tandem is that too much of a burden on the processor and will it slow things down too much to make it worthwhile?

I ask because I have one app doing both processes right now but it isn’t able to work exactly as I envisioned it, and I don’t want to pull it apart and remake it as two apps if there is no good reason to do so.

Thanks in advance :smiley:

PS: Does anyone know what an error code -1409 is? I have googled it and can’t find out.