In a paper published February 7th 2012 titled Ultrafast heating as a sufficient stimulus for magnetization reversal in a ferrimagnet the authors demonstrate that very high-speed burst of laser energy can write a bit to a magnetic media in 5 picoseconds (5×10-12), or the time it takes light to travel 1/20th of an inch). This in theory could change the speed of writing data to a disk or tape from megabytes/second to gigabytes/second.
However, the only way to read the data is with a magnetic head, which still operates at megabytes/second. This makes this process only practical for writing data with a very, very low probability of ever being read again - stone dead data!
Action Item: This technology could be of great interest to archive disk and tape systems. Enterprise data centers will continue to replace high-speed disks with flash devices. Hard disk suppliers such as Seagate will focus on high capacity disks, which will continue to be media-of-choice for low-cost, low-access storage.
Footnotes: See additional comments and input from one of the original authors in the alert "Limits of Magnetic Disk Reading Speed".