How to Verify if a WD Drive is 4K



How to verify if a WD drive is 4K

** For Windows and macOS instructions, please refer to Answer ID 26255: How To Verify if a Drive is 4k on Windows or macOS


Below is an overview of 4K native, 512 native, 512 emulated and an explanation of Advanced Format, followed by the drive specification examples.

Overview of different sector sizes:

Format type Logical bytes per sector Physical bytes per sector
4K native (4Kn) 4096 4096
512 native (512n) 512 512
512 emulated (512e) 512 4096

What is 4K native?
4K native (4Kn) is a drive with sectors that contain 4096 (4K) bytes.

Sector size:
4096 bytes Physical Sectors

This is a 4K drive.

What is 512 native?
512 native (512n) is a drive with sectors that contain 512 bytes.

Sector size:
512 bytes Physical Sectors

Please note the model numbers which are 512 native (512n) are not 4K drives.
They are 512 physical bytes per sector.

It is expressed as-
512 native model number: 512 native (512 logical / 512 physical)


What is 512 emulated?
512 emulated (512e) is a drive that physically has sector sizes of 4096 bytes. This is a 4K drive.

The purpose of emulating 512 bytes (512e) is for the new devices to be used with Operating Systems that do not support 4K native sectors yet.

The drive transparently maps 512-byte logical blocks into the drive's 4K physical sectors.

Sector size:
512 bytes 512 bytes 512 bytes 512 bytes 512 bytes 512 bytes 512 bytes 512 bytes Logical Sectors
4096 bytes Physical Sectors


It is expressed as-
512 emulation model number: 512 emulated (512 logical / 4K physical)

Here is an image depicting the drive transparently mapping 512-byte logical blocks into the drive’s 4K physical sectors.


What is Advanced Format (AF)?

Advanced format is a term for the industry standard increasing the physical sector size from 512 bytes to a more efficient 4096 (4K) byte sector size.

An advanced format drive is 4K.

Below is a link containing more information regarding Advanced Format (AF).

Advanced Format Technology Brief
http://products.wdc.com/library/WhitePapers/ENG/2579-771430.pdf


The drive specification sheet lists whether the drive is advanced format, the logical sector size (also referred to as emulated) and/or the physical sector size (also referred to as native).



In the specification, it lists:
512 emulation model number: 512 emulated (512 logical / 4K physical)
512 native model number: 512 native (512 logical / 512 physical)

The model numbers which are 512 emulated (512e) are 4K drives. They physically have 4096 bytes per sector.

Please note the model numbers which are 512 native (512n) are not 4K drives. They are 512 physical bytes per sector.


In the specification sheet, it says “Yes” to Advanced format. Advanced format means these drives have a physical sector size of 4,096 bytes.

They are 4K, and logical sector size emulates 512 bytes sector size.

They are 512 emulation model number: 512 emulated (512 logical / 4K physical).

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