Shingled magnetic recording

This approach was selected because, if the writing head is made too narrow, it cannot provide the very high fields required in the recording layer of the disk.

Device-managed SMR devices hide this complexity by managing it in the firmware, presenting an interface like any other hard disk.

[6] While SMR drives can use DRAM, flash memory, and even a portion of their own platter reserved for use with CMR instead of SMR,[7] as a cache to improve writing performance, continuous writing of large amount of data is noticeably slower than with CMR drives.

[8][9][10] Seagate started shipping device-managed SMR hard drives in September 2013, stating an increase in overall capacity of about 25% compared to non-shingled storage.

A United States class-action suit against Western Digital alleging that the technology is inferior was settled on or before August 27, 2021.

[16][14] Heavily overlapped (shingled) tracks also appeared earlier in the consumer helical scan video cassette recorders (VCRs) that were popular in the 1980s and 1990s.

In Extended Play (EP or SLP) mode, both VHS and Betamax reduced the track pitch by a factor of three.

Since the host manages the shingled nature of the storage, it is required to write sequentially so as to not destroy existing data.

The drive is capable of managing the shingled nature of the storage and will execute any command the host gives it, regardless of if it is sequential or not.

The new version introduces a new type of "domains and realms zoned block devices" that allow for non-contiguous LBAs, and it can benefits for SATA SSDs.

One example of the use case is Dropbox's Magic Storage system, which runs the on-disk extents in an append-only way.

[41][42] Adjusting the SMR/CMR setting helps suit the drive to the current workload of "hot" and "cold" data.

[21] SMR drives have received criticism online for slow read / write speeds and low stability.