Play CICS file-control programs against real VSAM datasets

VSAM is now a host engine of its own. A program that reads records rather than rows binds its CICS FILE operands to datasets in the application's settings — one row per FILE the program declares, so the map cannot drift from the copybook — and a blank dataset is refused by name rather than silently falling back. DATASET is accepted wherever CICS accepts it as a synonym for FILE.

Reads and writes reach the real dataset through a CoreIQ dataset endpoint, either the remote dataset server or a host that reads its own datasets. Routing follows the endpoint's type rather than whatever name your site gave it, and the dataset's key window is checked against the copybook when the session opens so a disagreement refuses the session instead of quietly reading the wrong record.

Without a host, the same program still runs: records are seeded locally from a reviewable text file beside the sources, and a record whose length does not match the copybook is rejected when the session opens, naming both lengths.