Conventional magnetic recording (CMR)
Perpendicular magnetic recording with non-overlapping tracks so any sector can be rewritten in place.
CMR (also called conventional or non-shingled layout in vendor catalogs) writes concentric tracks with guard bands so a rewrite to one track does not trim its neighbors. On modern shipping drives the underlying magnetization is usually perpendicular (PMR); “CMR” is the product-behavior label vendors use to contrast with SMR. Because in-place updates do not force band rewrite, CMR remains the default choice for mixed random I/O, RAID, and any stack that assumes a traditional block device. Seagate’s public CMR/SMR matrix lists recording technology per SKU—capacity alone does not reveal the layout.
Relations
- related
- pmr, smr, hdd, nearline-hdd
- supersedes
- longitudinal-recording
Advantages
- Random rewrite without track-band garbage collection typical of SMR.