Viewstamped Replication question

Imagine a very simple VR system with a single group, in which objects are just integers with atomic increment and decrement operations. In normal case operation (no view changes), how many synchronous disk writes are required by the primary to execute and commit a simple transaction incrementing one integer? How many writes are required by the backups?

Answers need only be a few sentences.

Turn in your answer on paper at the start of class. Be sure both your SUNet ID and your name are on the paper.

SCPD students may submit via SCPD before the start of class.