Basically, write heads are larger than read heads, but neither is going to get any smaller anytime soon. To get more data onto the platter, you can squeeze tracks together. The read head can still read each track individually, but the write head has to update multiple tracks at once, and this process can cascade.
That tracks are overlapped from the perspective of the write head is why it's called "shingled", like on a roof, and not because of a herpes zoster infection--which is the first thought I had :)
Comments and public postings are copyrighted by their creators.
Linux is a registered trademark of Linus Torvalds