I have a new to me MC-4VAE with the OSP 5020M control. No DNC option. BB1 memory is quite small. I've read that you can store programs in BB0. There are files listed in that directory BUT I don't know what can be deleted. I think POL files are configuration files for the control....?
You CAN store files in BB0 but that is all, you can NOT run programs from there.
POL files are Power On Load files, these are system files that are loaded up when you turn on the machine.
Not something that is a user editable file generally.