Re: Start making archive drives
I'm guessing it won't work. At the very best you'd have tracks twice the length, but you'd have to slow down the disk rotation speed to half both to maintain the aerodynamics that floats the head and to reduce stress on the bigger disk to a manageable level. Data bandwidth would decrease as data size increased. At worst vibrational instabilities would kill the idea. (General engineering rule: the bigger it is, the less stiff it can be).
If the manufacturers can get the price of a 4Tb 3.5 inch disk down to the £35 which has been the price of every previous size of disk drive at the time it was superceded, they'll be in business for a while yet. Get HAMR and/or BPM to market and sell 40Tb disks for £35, and I doubt Flash will ever compete.
The dark horse is ReRAM. I think it may kill flash first, followed by disks, both within 15 years of today.