A hard disk drive is a data storage device that consists of one or more platters (rigid rapidly rotating disks coated with magnetic material), to which data is written using a magnetic head. HDDs are a type of non-volatile memory hardware, retaining stored data even when powered off. Today’s laptop typically come with a hard disk that contains several billion bytes (gigabytes) of storage.
How is data read and stored on a hard drive?
Data sent to and read from the hard drive is interpreted by the disk controller, which tells the hard drive what to do and how to move the components in the drive. When the operating system needs to read or write information, it examines the hard drive’s File Allocation Table (FAT) to determine file location and available write areas. Once they have been determined, the disk controller instructs the actuator to move the read/write arm and align the read/write head. Because files are often scattered throughout the platter, the head needs to move to different locations to access all information.
All information stored on a traditional hard drive, is done magnetically. After completing the above steps, if the computer needs to read information from the hard drive, it would read the magnetic polarities on the platter. One side of the magnetic polarity is 0, and the other is 1. Reading this as binary data, the computer can understand what the data is on the platter. For the computer to write information to the platter, the read/write head aligns the magnetic polarities, writing 0’s and 1’s that can be read later.
Hard Disk Drive Troubleshooting
The hard drive in your computer is used over and over, each time you’re doing something that involves reading or writing data to the disk. It’s normal, then, to eventually run into a problem with the device.
One of the most common issues is a hard drive that’s making noise, and the best first step in troubleshooting a hard drive malfunction of any kind is to run a hard drive test.
Windows includes a built-in tool called (chkdsk) that helps identify and maybe even correct various hard drive errors. You can run the graphical version of this tool in most versions of Windows.
Lots of free programs can test a hard drive for issues that might ultimately lead to you needing to replace the drive. Some of them can also measure performance like the seek time.