cctech Digest, Vol 44, Issue 10

[Paul Berger]

On 2018-05-11 2:37 PM, John Ames via cctech wrote:
>> Looking at modern hard disks, I'm unconvinced we could even mass-produce
>> something like that today.
>>
>> A 40mm radius is comparable to a 3.5" disk, which are generally 5,400-7,200
>> RPM. 15,000 RPM is the fastest available, but those tend to be low-capacity and
>> expensive, and are often 2.5" drives with a huge heatsink. We could perhaps
>> rotate a very narrow smaller cylinder faster still but then the capacity
>> suffers further, and the seek time would start to dominate.
> I Am Not An Engineer(tm) but it seems to me that a taller cylinder
> should be less prone to wobbling on its axis than a flat disk,
> particularly if it's built at the scale of the drums I've seen at the
> CHM where there's room enough to really bolt that sucker down. Bit
> different than a 3.5" box with a stack of thin metal platters in it,
> I'd think.
They are not even metal platters anymore they have been glass for 
several years now, glass is more rigid and can apparently be made 
smoother than metal.