Pluck-filled platter-stuff: Bold disk drive makers fatten up

And store more data, of course

Analysis Disk drives are getting more platters so they can be fattened up with more data.

HDD electric motor maker Nidec thinks 3.5in nearline drives will increase their thickness from today's 1 to 2 inches so they can cram in more data.

Seagate's 10TB, helium-filled, Enterprise Capacity drive is 1.028in (26.11mm) thick, the z-height measure, with 7 x 1.43TB platters inside.

Stifel MD Aaron Rakers writes: "The industry overall is currently going from seven platters to eight platters per drive and 1TB per platter to 1.33TB per platter, but even eight 1.33TB platters only equates to 12TB per drive."

Seagate has a 12TB version of this drive coming, which would mean 7 x 1.7TB platters or, if Rakers is right, 8 x 1.33TB. But this 12TB capacity level has already been overtaken by 2.5in solid state drives, with Samsung shipping a 15.36TB SSD.

Seagate itself has demonstrated a 60TB, 3.5in SSD.

For disk drives to keep their role as the most cost-effective nearline storage drive format, you see an argument that capacities have to rise to match SSDs. If the casing thickness was doubled then more platters could be crammed inside. We can't assume a simple platter count doubling because the casing itself takes up space, so let's assume we can add another six platters with a 2in z-height.

With 14 x 1.33TB platters that would mean a capacity rise to 18.6TB. And if HAMR (Heat-Assisted Magnetic Recording) comes around the block then we can maybe envisage 2TB and then 2.5TB platters, meaning 28TB and 35TB drives. Shingling tracks could add more, 25 per cent perhaps.

These numbers don't look too unlikely. However, if QLC (4bits/cell) 3D flash comes along, witness Toshiba's concept of a 100TB SSD, then the disk drive maker's calculations may be thrown into disarray.

The storage magnetic media world is facing interesting times with another wrinkle being the IO rate of such enormous capacity disk drives, not to mention RAID rebuild times, which will virtually guarantee object storage and erasure coding being used to overcome what threatens to be an enormous bottleneck. Data obesity is both opportunity and threat for the platter people. ®

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