I can see that you are trying very hard to fit a new picture into an old frame. But with new technology there is always new possibilities. For example, what I am thinking is: with the new laser write head, it doesn't necessarily require the head to stay very close to the platter since laser doesn't fade away with longer distance, which may enable a design that the head turns(the platter doesn't have to be round) instead of spinning the platter; hence the "Data rate is a product of [density * RPM]" statement falls apart. What is more, if the cost is justified, one may even design a disk with multiple write heads to increase the bandwidth since now we are free from the fluid mechanic interaction between the head and the platter. Both of these may lead to independent increase of data rate. I am having these thoughts because it's been an endless effort trying to remove the mechanical parts from a HDD(SSD was an attempt). With Ostler's new technology, this once again becomes possible. It is wise to think outside the box at this time. Cheers, Alex On Wed, Apr 25, 2012 at 9:20 AM, Stan Hoeppner <stan@xxxxxxxxxxxxxxxxx> wrote: > On 4/23/2012 10:26 AM, Alex wrote: > >> It looks like to me Ostler's team's work does independently lead to an >> increase in areal density and writing speed, and >> there is not fixed relation between these two. > > That's because you've not taken 60 seconds to actually think about this > logically. > > Data rate is a product of [density * RPM]. To increase data rate we > must increase one of these two. Making the R/W head simply punch holes > faster won't increase data rate. It will allow simply allow us to > increase the other two without the R/W head becoming a bottleneck. > > Designing the R/W head to punch bits 1000x faster cannot independently > increase throughput. The platter must either have more bits per inch or > they must spin faster. Period. > > Thus, the only way this laser R/W head will increase throughput is if it > simultaneously writes more bits per inch, which increases density, > allowing. So again, unless it increases density, the faster punching > speed doesn't increase throughput. > > -- > Stan -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
