Particle remover of HDD for Load/Unload Application
Original Publication Date: 2002-Jan-20
Included in the Prior Art Database: 2003-Jun-19
This document is describing a methodology in order to enhance the HDD reliability . As the recording density is getting higher , the clearance between the head and the disk is designed to be smaller and smaller in order to achieve the high density recording. But one of the difficulties for lowering the fly height is the "high fly write" phenomena. The Disk enclosure is produced in a c"lass 100" clean room , which means there are 100 submicron-particles in a cubic inch . So inside DE , there thought to be tens of particles. Theoretically speaking , it is possible for a flying head to encounter the particles . Most of the case , the particle is thought to be wiped out from the disk surface by the flying head , but it can happen for a head to bite it between the head and disk . The possibility of this case is thought to have some dependency to the head fly height . In that case , a head jumps over the particle , which means that the head flies higher for that period . If that happens while data_writing , the written data is not magnetized on the media properly , because the head was not enough close to the disk to write the data clearly at that time. This phenomena is called as "high fly write" , which can cause the data integrity problem . The newly designed approach is aiming for reducing the possibility of "high fly write" . Usually, the particles inside DE is wiped out by the flying head , because the head fly height is relatively smaller than the size of the particle. But when the head is loaded down to the disk from the ramp after the power on or a sleep mode , the probability for the head to stamp down the particle is much higher than usual . We usually see the higher occurrence of the "high fly write" at the first write operation after the head load , and this can be explained by the scenario above.