30TB HAMDisk Drives Get Less Shingled Capacity Increase Than You'd Think
Blocks&Files, Tuesday, January 23rd, 2024
Shingled HAMR disk drives get a lower capacity increase than existing conventional drives. Is this due to HAMR technology itself or higher capacity drive tracks being narrower with less scope for shingling?
SMR (shingled magnetic recording), with its overlapped write tracks, delivers a capacity increase over PMR (perpendicular magnetic recording), also known as conventional magnetic recording (CMR), because a read track is narrower than the write track. A read head, which senses bit area magnetic direction, is narrower than a write head, which writes bit area magnetic direction. If you partially overlap write tracks but preserve the read tracks, you can add 17 to 20 percent or more capacity to the disk drive. You basically get more free physical space on the drive and can add extra tracks to the disk platters.