Advanced Format

Advanced Format (AF) is any disk sector format used to store data in HDDs and SSDs that exceeds 528 bytes per sector, frequently 4096, 4112, 4160, or 4224-byte sectors. Larger sectors of an Advanced Format Drive (AFD) enable the integration of stronger error correction algorithms to maintain data integrity at higher storage densities.

Advanced Format (AF) is any disk sector format used to store data in HDDs and SSDs that exceeds 528 bytes per sector, frequently 4096, 4112, 4160, or 4224-byte sectors. Larger sectors of an Advanced Format Drive (AFD) enable the integration of stronger error correction algorithms to maintain data integrity at higher storage densities.

512 emulation (512e)

Many host computer hardware and software components assume the hard drive is configured around 512-byte sector boundaries. This includes a broad range of items including chipsets, operating systems, database engines, hard drive partitioning and imaging tools, backup and file system utilities as well as a small fraction of other software applications. In order to maintain compatibility with legacy computing components, many hard disk drive suppliers support Advanced Format technologies on the recording media coupled with 512-byte conversion firmware. Hard drives configured with 4096-byte physical sectors with 512-byte firmware are referred to as Advanced Format 512e, or 512 emulation drives. On 512e drives, one LBA is equal to 512 bytes. The translation of the native 4096, 4112, 4160, or 4224-byte physical format (with 0, 8, 64, or 128-byte Data Integrity Fields) to a virtual 512, 520 or 528-byte increment is transparent to the entity accessing the hard disk drive. Read and write commands are issued to Advanced Format drives in the same format as legacy drives. However, during the read process, the Advanced Format hard drive loads the entire 4096-byte sector containing the requested 512-byte data into memory located on the drive. The emulation firmware extracts and re-formats the specific data into a 512-byte chunk before sending the data to the host. The entire process typically occurs with little or no degradation in performance. The translation process is more complicated when writing data that is not a multiple of 4K or not aligned to a 4K boundary. In these instances, the hard drive must read the entire 4096-byte sector containing the targeted data into internal memory, integrate the new data into the previously existing data and then rewrite the entire 4096-byte sector onto the disk media. This operation, known as read-modify-write (RMW), can require additional revolution of the magnetic disks, resulting in a perceptible performance impact to the system user. Performance analysis conducted by IDEMA and the hard drive vendors indicates that approximately five to ten percent of all write operations in a typical business PC user environment may be misaligned and a RMW performance penalty incurred. When using Advanced Format drives with legacy operating systems, it is important to realign the disk drive using software provided by the hard disk manufacturer. Disk realignment is necessary to avoid a performance degrading condition known as cluster straddling where a shifted partition causes filesystem clusters to span partial physical disk sectors. Since cluster-to-sector alignment is determined when creating hard drive partitions, the realignment software is used after partitioning the disk. This can help reduce the number of unaligned writes generated by the computing ecosystem. Further activities to make applications ready for the transition to Advanced Format technologies were spearheaded by the Advanced Format Technology Committee (formerly Long Data Sector Committee) and by the hard disk drive manufacturers.

4K native (4Kn)

For hard disk drives working in the 4K native mode, there is no emulation layer in place, and the disk media directly exposes its 4096, 4112, 4160, or 4224-byte physical sector size to the system firmware and operating system. That way, the externally visible logical sectors organization of the 4K native drives is directly mapped to their internal physical sectors organization. Since April 2014, enterprise-class 4K native hard disk drives have been available on the market. Readiness of the support for 4096-byte logical sectors within operating systems differs among their types, vendors and versions. For example, Microsoft Windows supports 4K native drives since Windows 8 and Windows Server 2012¹ (both released in 2012) in UEFI. 4K native drives may work on older operating systems such as Windows 7, but cannot be used as boot drive. Linux supports 4K native drives since the Linux kernel version 2.6.31 and version 2.17 (released in 2009¹ and 2010, respectively). The color version of the logo indicating a 4K native drive is somewhat different from the 512e logo, featuring four rounded corners, a blue background, and text "4Kn" at the center of the logo. IDEMA: Advanced Format Technology (archived on September 29, 2011) Coughlin Associates: Aligning with the Future of Storage (archived on May 5, 2012) Western Digital: Advanced Format White Paper (September 2018) and its older version (April 2010) Hitachi Global Storage Technologies: Advanced Format Technology Brief The Tech Report: Western Digital brings Advanced Format to Caviar Green Dell: Support: System Image Support for Advanced Format Hard Drives on Dell Business Client Notebooks and Desktops

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