I recently wanted to buy a new Harddisk. I did not want one that uses "shingled magnetic recording" because thats awfully slow. Instead I looked for a "perpendicular magnetic recording" HDD, but I learned thats not a thing anymore. Instead I could buy CMR disks. For those getting here by google looking for a quick answer: CMR=PMR. For those who want to know why PMR was renamed to CMR and why SMR disks are slow: read on