Final answer:
SSI, Cookie Support, Tracing and Logging, and Persistent Connections are basic z/OS-specific HTTP functions essential for the core operation of the IBM mainframe operating system's web server.
Step-by-step explanation:
SSI (Server Side Includes), Cookie Support, Tracing and Logging, and Persistent Connections are considered basic types of z/OS-specific HTTP functions. These functions are integral to the core operation of the HTTP server provided by z/OS, which is IBM's mainframe operating system. They are not add-ons or external features but rather essential components that enable the web server to manage communications, user data, and diagnostics effectively.