Hard drive noises

Whenever mechanical hard drives are accessed, various noises will be heard, including clicking, whirring, and the occasional "grinding," which is just a series of subtle click sounds close together. These sounds happen because the drive platters are spinning up, and the head is being swiftly moved from position to position on the drive and then seated back in a secure location. As such, if the drive is spun down and you access it, you may hear something like a whirr (platter spinning up) followed by a click (heads unseating) and a subtle grinding noise (heads navigating rapidly), then another click (heads seating). Depending on the applications used, drives may make different levels of these sounds.

Mac OS X vs Windows

Some people have wondered why for the same machine running both the Mac OS and Windows (or other operating system), they hear differences in these noises:

Apple Discussion poster "Orzei" writes:

"I just got a new MacBook, which means a new hard drive. When using Mac, I seriously thought I had gotten a SSD it was so quiet. But every time I use Windows, the "sound of it working" is very loud and sounds awful. But, back to using Mac, it is its quiet self. Is anyone else experiencing this (and is there a fix?)"

In OS X, Apple has optimized drive performance by incorporating technologies that actively defragment files on the drive, keeping the data on the drive as contiguous as possible. There are also file caching and virtual memory differences that also are in favor of the Mac OS, and result in less use of the drive. This means that in comparison to Windows, the Mac hard drive in general will be a little quieter as it will access the drive less.

Additionally, there are driver differences between the Mac and Windows, which gives the Mac OS on Apple hardware more finely tuned control over power management. As such, the drive may stay on longer in Windows than in the Mac.

Since this is just a difference in how the hard drives are utilized by the operating system, you can expect it to happen anytime you are running Windows, be it in Boot Camp or when using virtualization solutions such as Parallels or VMware.

Problems

On portable computers, most hard drives have "Sudden Motion Sensor" technologies that will detect any jarring of the computer. Since this can damage the heads and platters if they touch, if you move the computer suddenly you may hear a louder click or two as the heads are parked away from the platters.

If for some reason the heads do get damaged, you will see a notable lack of function or a decrease in performance of the computer (crashes, slow loading, and system hangs), along with either no sounds from the drive or repetitive patterns of grinds, clicks, and whirrs as the drive tries to complete read/write commands that the OS is giving it. On rare occasions these errors are just due to some faulty setting in the drive's firmware and a reset can fix the problem. More than likely, however, the drive has "gone bad," and in these cases the safest thing to do is assume the worst and replace the drive. There is no point to risking data loss with a faulty drive, and they're not that expensive.

If you need data off the drive and it is not working in your computer, you can try a few things. First and foremost is to run Disk Utility (and other utility programs--DiskWarrior, Drive Genius, TechTool Pro, and Disk Tools Pro) and do a repair on the drive. If there is a corruption in the volume structure on the drive, then these can possibly fix the problem and allow you to read the data. The second thing to try is to read the drive using another computer. If you have a non-Mac computer that supports reading HFS drives (software is available for Windows to read HFS formats--MacDrive, HFSExplorer), then install the drive in that computer and try reading it. In addition to using another computer, you may try putting the drive in an external FireWire or USB enclosure to read. Many times having a new controller access the drive can allow an operating system to read from the drive again. External enclosures can be very cheap, and are available at multiple vendors including: NewEgg, OWC, and MacMall.

Resources