Assertion: hard drive's platter | /r/CapableOf | give one servo surface
Facets:
value: for head positioning
type: PURPOSE
Source sentences:
text: The remaining 3 platters give 5 data surfaces and one servo surface for head positioning, being the upper surface of the center platter.
text: The remaining 10 platters give 19 data surfaces and one servo surface for head positioning, again being the upper surface of the center platter.