A fault-tolerant implementation of the CTRON basic operating system

Tandem Computers has developed an operating system based on the CTRON specifications and implemented it on our fault-tolerant Integrity C series hardware platform (C/S2). This work has been done in conjunction with the Network Information Systems Laboratory of Nippon Telegraph and Telephone Corporation (NTT). The current version of this operating system is presently being used in a production system within NTT. We are now working on enhancements to the system to adapt it to the latest hardware models in the Integrity Series. In this paper, we make a brief overview of our project and describe how we have integrated Tandem´s fault-tolerant architecture for the Integrity Series with CTRON and its definitions for a common set of operating system interfaces. In implementing CTRON on our hardware fault-tolerant platform, one of our primary goals was to ensure that application programs did not have to be modified to accrue the advantages of fault-tolerant operation. CTRON interfaces are supported unchanged. Thus, application programs which adhere to specified CTRON interfaces will run unmodified in a fault-tolerant environment. No additional modifications to checkpoint state or effect process recovery are necessary at the application programming level to take full advantage of the fault-tolerant features of the system