------------------ and ------------------- are the two kind of software. (Fill in the blank gap).

Can you provide some background for this?

My guess would be either (proprietary : open source) or (Operating system : Applications)
More info would be needed

Commercial and public domain. Those are the only 2 types of software that exist.

As said it all depends on the context of the question and the topic in regards its being asked in.

Generally it could be as cmeeks said or as califdadof3 said. More specifically it could be a variety of things. For example if the context was network security it could be IDS (Intrusion Detection System) and IPS (Intrusion Prevention System).