“The threaded kernel (TK) is an independent internal interface to low-level OS interfaces such as memory, events, task creation, etc. The TK interface is booted one time in an address space and its services are available to any task in that address space. SAS 9.1.3 Foundation makes use of TK services. Moreover, SAS is itself initiated as a TK-created task rather than being entered directly as the job step task or via ATTACH. SAS 9.1.3 Foundation runs, in effect, as a TK application. The introduction of TK into the SAS environment enables SAS to invoke OS services in a portable manner on multiple platforms, thereby enabling concurrent operations on multiple processors from multiple OS tasks.”