https://www.theregister.co.uk/2019/10/07/wd_and_seagate_mull_10platter_hdds_stopgap_or_bff/

With 10-platter conventionally recorded disk drives touting capacities of up to 20TB by 2021, the arrival of HAMR and MAMR drives could slip back to 2022.

Trendfocus, a research firm specialising in data storage, suggests the launch of conventional technology in 18TB capacities in the second half of 2020 could delay the adoption of shingled magnetic recording (SMR) until the following year. Such SMR drives would have a 20TB capacity.