Key Problems Study And System Design Of Shingled Magnetic Recording With Ultra-High Areal Density

As one of the world’s most rapid developing technology, information technique has played a very important role in propelling the society forward. The magnetic storage system is low cost, reliable and it takes the main position in various storage systems based on its ultra-high areal density and rapid development. But the traditional magnetic recording technology cannot go ahead in the coming years because of superparamagnetic effect. Therefore, it is high needed to research new magnetic recording technology to support the increase of areal density. Ultra-high areal density is the goal for magnetic recording and the problem lies in how to do research on the recording media and magnetic head to reach the areal density of10Tbit/in2.Shingled magnetic recording (SMR) applies the wide writing pole and it can provide enhanced writing capability without change the structure of magnetic head heavily. So it is considered to be a feasible way to reach10Tbit/in2of areal density. Most researches about SMR focus on the file management algorithm and data arrangement method. However, this paper focuses on other issues about the key problems of implementing areal density of10Tbit/in2by applying SMR. This paper also explored the feasibility about using shingled thermally assisted magnetic recording and combining SMR and ECC to reach10Tbit/in. The main innovation work contains:(1) The FEM and micromagnetic simulation method is introduced in this paper to calculate different shingled head for10Tbit/in2. We analyzed various width of writing pole, driving field, shield gap and bevel angle of the tapered tip to minimize the negative effect from shingled head.(2) This paper analyzed the special phenomenon in the ultra-high shingled magnetic recording, such as rounded corner effect and aggregation effect. The rounded corner effect gives implications on producing steeper filed gradient, optimizing distribution of stray field and improving performance of the recording system. Besides, we also explored the skew effect and the results suggest that larger corner angle and narrow skew range are recommended to enhance the writing field and avoid the adjacent track erasure. The analysis also suggests that hot spot disk data in a safe region has lower possibility to be potentially disrupted.(3) This paper originally proposed calculating algorithm of effective field and field gradient under the way of corner recording, and the bit error rate is deduced to measure the writing performance of SMR.(4) The shingled thermally assisted magnetic recording is introduced to overtake the disadvantage of HAMR. The results show that the shingle thermally assisted magnetic recording has advantages in enhancing the writability and improving side-erasure gradient, and it has better recording performance than other magnetic recording technology.(5) This paper also explored SMR with ECC media to reach the areal density of10Tbit/in2. The switching field can be notably reduced while keeping sufficient thermal stability by using ECC media. But SMR with ECC media has new problems of angular dependence of coercivity. According to calculation, if bits are properly arranged, the adjacent bits can suffer minimized encroachment caused by variation of angularly induced switching field, and attain a satisfactory bit error rate.The SMR head designs based on researchment above have enhanced the head writability and system signal-to-noise ratio, which gives implications to achieve the areal density of10Tbit/in2.