Encontrei algumas informações no Fórum de diagnósticos do PC e faz sentido. O nome do funil de nome provavelmente tem a ver com o padrão formado pelos setores acessados (das bordas ao centro)
Funnel Seek (aka Butterfly Seek) - tests track zero first, and then steps out to test the outermost track next. It then steps back and tests track one and steps out to test the next-to-outermost track. This operation continues until the whole disk has been tested. The butterfly seek is the most rigorous seek test.