Project ForgeOperating Systems
I/O Subsystem & File Systems
GATE 2008
Medium
For a magnetic disk with concentric circular tracks, the seek latency is not linearly proportional to the seek distance due to
- Anon-uniform distribution of requests
- arm starting and stopping inertia
- Chigher capacity of tracks on the periphery of the platter
- Duse of unfair arm scheduling policies
Explanation
The disk arm must physically accelerate and decelerate (overcoming inertia) for each seek, so seek time has a fixed startup/settling overhead component in addition to a distance-dependent component — making the relationship non-linear, not purely proportional to distance.
Source: GATE CS 2008 (2008)
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