Components of Hard Disks
There are two types of hard disks—the Parallel ATA hard drive and the Serial ATA hard drive, each possessing different components. We explain each of their significant components below:
Components of a PATA Hard Drive
The platters are the components that store the data saved on a hard drive. They are disc-shaped, looking a lot like floppy discs. Platters are made of glass, aluminum, or ceramic and are coated in a ferromagnetic material for permanent data storage. The number of platters in a hard disk depends on the size and capacity of the drive, but most would have two or more.
The spindle holds the platters in place, somewhat fixed to the chassis, and rotates them as required. Like other disc storages, the platters need to spin before the data stored on them can be accessed, and that responsibility falls on the spindle. Hard drives have varying spinning speeds, ranging from 3,200 to 7,200 rates per minute for desktops and laptops. However, higher speeds are available for high-performance computers.
The read and write arm has the read/write heads at its tip, and it controls the movement of the heads across the surface of the platters. The read/write heads come in contact with the magnetic surface and do the reading/writing by converting it into an electric current. The arm’s job is to ensure the head is in the proper position to read the requested data.
The actuator intercedes between the circuit board and the read/write arm. It takes instructions from the circuit board and communicates them to the arm. It oversees the transfer of files to and fro the platters and tells the arm which head to move and where to move it depending on which data is being written or read.
The circuit board serves as the drive’s motherboard and is often unique to each hard disk. The circuit board controls power and ensures that the hard disk functions. It controls the read/write arm and heads by communicating with the actuator. It also communicates with the rest of the computer unit.
Components of a SATA Hard Drive
The SATA hard drive has connectors and ports responsible for drawing power from the computer unit, transferring data between the drive and the computer, and configuring the drive’s operation mode. Sometimes, it may have a PATA-style power connector.
The logic board functions much the same as the circuit board on the PATA drive, though it looks different. The logic board has several integrated chips on the board, and among them are the controller, RAM, and motor driver chips.
The Spindle motor is connected to the logic board and drives the discs’ rotation, like in PATA drives. The higher the rates per minute, the more power it consumes.
Opening a hard disk, you would find the core assembly inside it. This assembly includes an air filter and a port to the logic board. However, the most outstanding are the discs themselves, called platters. The platters are the same as the ones in PATA hard drives.
Hard disk drives usually have two or more discs, each with two sides. The board reads from and writes to the discs utilizing carefully tuned arms that look like the tone arms on vinyl record players. At the end of each arm is a head, where the communication between the disc and the arm occurs.
At the base of each arm is an actuator called a voice coil. It drives the arm with extreme accuracy as it moves throughout the surface area of the disk at really high speeds.
The Technology of Magnetic Recording
Magnetic recording, or magnetic storage, is the storage of digital or electronic data on a magnetized medium or material. Magnetic recording is a type of non-volatile memory, i.e., it can retain the information stored on it even if it is disconnected from power.
The first magnetic tape recorder was developed in 1928 by Fritz Pfleumer, though magnetic storage had been discovered decades earlier. The earliest magnetic storage devices (MSDs) could only record analog audio signals. Still, over years of development, most MSDs now record digital data, including videos, images, audio, colors, text, and more.
How does it really work?
We’ve mentioned earlier that the read/write heads store and retrieve data from the platters. These heads detect and modify the magnetization of the material directly under them. Since computers store data in ones and zeros, the magnetic poles north and south represent either one or zero.
A magnetic surface is divided into many small-sized magnetic regions called magnetic domains. Each domain has hundreds of magnetic grains, which are typically 10nm in size, and each of them generates a magnetic field. For reliable storage of data, the magnetic material must be able to resist self-demagnetization. This is because when the spindle rotates the platters, over time, the written magnetic domains degrade. Hence, a strong magnetic material with high coercivity, like neodymium, must be used.
When the platters for the hard drives are manufactured, they’re covered by a ferromagnetic material, i.e., a material that can be magnetized. However, the platters are not magnetized from the factory. The write head will generate a strong magnetic field to store data on the platter to magnetize the region directly beneath it. And to retrieve data from the drive, the read head will detect the magnetization of those regions.
What Is the Characteristic of the Neodymium Magnets in Hard Drives
Neodymium magnets are the strongest and most durable on the market. While there are different grades of neodymium magnets with varying levels of performance, they are generally strong and have high resistance against demagnetization forces. They can function effectively in high temperatures and can generate strong magnetic fields.
Compared to several other types of magnets, neodymium magnets are made from rare earth elements and are classified as permanent magnets because of their ability to retain magnetism permanently. Unlike weak ceramic magnets, which lose magnetism quickly, neodymium magnets are strong. And since they can hold magnetization permanently, they can’t quickly lose the data stored on them.
Common Practices for Destroying Hard Drive Data
Despite being useful to humans in the present digital age, some situations call for destroying the data stored on hard drives. This is usually because of the sensitive personal information stored on them. And one of the characteristics of magnetic storage is that data cannot be totally erased from them. Below are the most common ways to permanently destroy the data stored on hard drives.
This is usually the safest and most cost-effective way to destroy the data stored on a hard drive. It involves destroying the drive to pieces no larger than 2 millimeters, ensuring nothing can ever be recovered from them.
This is usually the go-to method for deleting data from hard drives. However, it is ineffective for permanent data destruction as recovery software can still recover the deleted data from the drive.
This involves overwriting the data stored on a drive or any other electronic medium so that the data can no longer be read.
- Data Overwrite
This is another form of data wipe where software writes new data over the existing one. This ensures that the old data is no longer accessible.
This involves demagnetizing the magnet in the hard drive by subjecting it to a strong opposing magnetic field. The only caveat is that any hard drive subjected to this process will become completely useless as it will never function again.