More Details About Hard Drives
Learn how hard disk drives manage data storage through concepts like track skew to optimize read efficiency, multi-zoned designs based on track geometry, and caching mechanisms. Understand how to calculate disk rotation times and data transfer durations using dimensional analysis for better system performance insight.
We'll cover the following...
Though we won’t spend too much time on it, there are some other interesting details about how hard drives operate.
Track skew
Many drives employ some kind of track skew to make sure that sequential reads can be properly serviced even ...
Sectors are often skewed like this because when switching from one track to another, the disk needs time to reposition the head (even to neighboring tracks). Without such skew, the head would be moved to the next track but the desired next block would have already rotated under the head, and thus the drive would have to wait almost the entire rotational delay to access the next block.
Multi-zoned disk drives
Another reality is that outer tracks tend to have more sectors than inner tracks, which is a result of geometry; there is simply more room out there. These tracks are often referred to as multi-zoned disk drives, where the disk is organized into multiple zones, and where a zone is consecutive set of tracks on a surface. Each zone has the same number of sectors per track, and outer zones have more sectors than inner zones.
Cache
Finally, an important part of any modern disk drive is its ...