Simon has just published an article about mainframe interop using Screen logic Integration (SLI). In it he very clearly describes the various ways of interfacing to a mainframe before drilling down into SLI.
I am a big Business Logic Interface (BLI) fan and dislike SLI as an approach but it does have its uses (e.g. when the mainframe code is too tangled to do BLI). The reason I dislike SLI is that in my experience it can very heavily load the mainframe which is fine if you are trying to sell mainframes but not so good otherwise.
I have a number of theories about mainframe interop and performance that I must blog about.
Anyway Simon’s article is well worth reading although it could be made more readable with a Blogcast J.