:(DELETE) This text describes "product name", is not an encyclopedic entry. In

computing Computing is any goal-oriented activity requiring, benefiting from, or creating computer, computing machinery. It includes the study and experimentation of algorithmic processes, and the development of both computer hardware, hardware and softw ...

, System Fault Tolerance (SFT) is a fault tolerant system built into

NetWare NetWare is a discontinued computer network operating system developed by Novell, Inc. It initially used cooperative multitasking to run various services on a personal computer, using the IPX network protocol. The final update release was ver ...

operating system An operating system (OS) is system software that manages computer hardware and software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ...

s. Three levels of fault tolerance exist: * SFT I 'Hot Fix' maps out bad disk blocks on the file system level to help ensure data integrity (fault tolerance on the disk-block level) * SFT II provides a

disk mirroring In Data storage device, data storage, disk mirroring is the Replication (computing), replication of logical disk volumes onto separate physical hard disks in Real-time computing, real time to ensure continuous availability. It is most commonly u ...

or duplexing system based on

RAID RAID (; redundant array of inexpensive disks or redundant array of independent disks) is a data storage virtualization technology that combines multiple physical Computer data storage, data storage components into one or more logical units for th ...

1; mirroring refers to two disk drives holding the same data, duplexing uses two data channels/controllers to connect the disks (fault tolerance on the disk level and optionally on the data-channel level). * SFT III is a server duplexing scheme where if a

server Server may refer to: Computing *Server (computing), a computer program or a device that provides requested information for other programs or devices, called clients. Role * Waiting staff, those who work at a restaurant or a bar attending custome ...

fails, a constantly synchronized server seamlessly takes its place (fault tolerance on the system level).

References

Novell NetWare 4.2 documentation
Novell NetWare {{comp-sci-stub