Spinning Rust – an Engineering Marvel!!

Before we talk about Performance lets, understand more about the “Spinning Rust”.

The old Hard Drives Platters were coated in Iron Oxide, which is nothing but “Rust”. Hence the device is called “Spinning Rust”. In Morden days platters are made up of complex alloy coating on glass platters. But the name is stuck to the device.

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Parts of Hard Disk Drive (HDD):

There are several highly specialised parts in this amazing machine.

Spindle Motor

The Drive platters rotate under the spindle motor’s power, which is designed to maintain a constant speed with the minimal vibration over a long period of time.

Read/Write head

The recording heads used for transmitting data to and from the platter are called read and write heads. Read/write heads are responsible for recording and playing back data stored on the disk platters’ magnetic layer.

Actuator and Arms

The read and write heads have to be precisely positioned over specific tracks. As heads arc very small, they are connected to disk arms that are thin, rigid, triangular pieces of lightweight alloys. Like everything else inside a disk drive, the disk arms are made with microscopic precision so that the read/write heads can be precisely positioned next to the platters quickly and accurately.

Logic Board

Disk drives all have internal target controllers that respond to commands from host or subsystem initiators. In addition to interoperating with the external initiator, the storage controller in a disk drive is responsible for executing the command within the drive. The software component of a disk drive controller is referred to as firmware and is typically stored in e-prom chips in the drive’s circuit board.

Disk Platters:

The physical media where the data is stored in the disk drive. The platter is made up of many layers.

  • Lubricant Layer:

1-2 mm layer of lubrication prevents friction between the protective layer and read/write head.

  • Protective Layer:

The protective overcoat layer protects the microscopic elements such as dust, water vapours and disk head crashes.

  • Media Layer:

This layer is made of magnetic material, usually an alloy of Cobalt and other metals, and is about 100 atoms thick.

  • Substrate:

The base of the platter is non-magnetic and is usually made from aluminium or glass.


animagraffs.comhas the Disk drive animation for better understanding.

Disk Drives has clear explanations about the disks.

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