>I see 60TB is the upper bound for 3.5 inch, so not much wrong with the title, is it?

Well the problem there is that it's a theoretical upper bound, which is another way of saying "we have not yet found a specific reason that 3.5 inch 60TB drives should be impossible with this technology". That is a far cry from "on their way".

This is similar to the announcements from Intel about advances in lithography. Intel announced the 32nm process technology in 2009 -- that process gives them a platform to refine and improve their technology.

So now, a top of the line Xeon is faster, has 10 multi-threaded cores, includes AES acceleration, and uses 20% less power than it's predecessor 3 years ago... thanks to that base technology.

If you're running a business that generates/consumes alot of storage, this announcement means that you need to start thinking about how to deal with a petabyte of storage capacity with performance characteristics similar to what you have today. (for 1/30th capacity)

HDD transfer speeds do increase as storage density's increase. It might be more accurate to say 30x the space but only square root (30) times the transfer speed.

Random access performance will be an issue, unless they work some magic on that, too. Same for bus-speeds.

Today you can fit about 96T into 4U if you squeeze a little. That's 48 spindles then, sharing the load.

With 60T drives that turns into 2.8P on the same 48 spindles.

At today's maximum SAS bus-speeds (roughly 10 GBit/s) it would take 33 days just to write such an array full (assuming all components can sustain that throughput).

And let's not get started on IOPS...

Anyway, it will be a while before 60T drives hit the shelves. Until then at least the bus-speed issues will probably be sorted out.