Multiple choice technology mainframe

How is a nonstop process pair implemented in Tandem systems?

  1. CheckPointing

  2. Mirrored Disk

  3. EXPAND

  4. RDF
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In Tandem (HP NonStop) systems, nonstop process pairs are implemented using Checkpointing. The active process periodically checkpoints its state to the backup process, ensuring failover capability. Mirrored Disk (B) provides data redundancy, EXPAND (C) is for network clustering, and RDF (D) handles remote data replication; none implement process pairs.

AI explanation

In HP/Tandem NonStop systems, fault tolerance for a process is implemented via the "process pair" model, where a primary process periodically sends checkpoint messages (containing state information) to a backup process running on a different processor. If the primary fails, the backup takes over from the last checkpoint, providing nonstop operation. This makes "CheckPointing" the correct mechanism. "Mirrored Disk" refers to NonStop's disk-level redundancy, not process-level fault tolerance. "EXPAND" is Tandem's proprietary wide-area networking protocol/software, unrelated to process pairs. "RDF" (Remote Duplicate Database Facility) is a disaster-recovery replication tool for databases across systems, not the process-pair mechanism itself.

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