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D-Link FAQ => ShareCenter FAQs => Topic started by: JavaLawyer on July 30, 2012, 07:05:50 AM

Title: DNS ShareCenter - AFT (Advanced Format Technology) Hard Drive Support
Post by: JavaLawyer on July 30, 2012, 07:05:50 AM
New HDDs are commonly manufactured with sectors of 4096 bytes and are called "AFT" or "Advanced Format Technology" HDDs. By strict definition, HDDs with sector sizes > 520 bytes are AFT.  This new formatting schema improves efficiently for storing large files and improves error correction and addressing.  Many legacy operating systems and NAS firmware aren't equipped to recognize the newer AFT HDDs, and require a software/firmware upgrade to enable AFT support.

By contrast, non AFT HDDs are segmented into sectors sized 520 bytes or less.

It's All About the Math...

Older PCs were manufactured with HDD addressing constraints integrated within the BIOS and OS. The following formula illustrates that the maximum calculable space supported by legacy HDDs is 2.2TB. Since 2.2 TB goes against the industry standard interval for HDD sizing, the largest commonly available supported legacy HDD is 2TB.

2(32 * 512)= 2,199,023,255,552 bytes = 2.2TB

32 = bits available per HDD address
512 = bytes per data block

Determining if a HDD is AFT

Short of explicit language on the HDD packaging, examining the HDD specifications and identifying the sector size can be used to determine of a HDD is AFT (sector size > 520 bytes) or non-AFT (sector size 520 bytes or less).

DNS-320L, DNS-327L, DNS-345

DNS-320, DNS-325

DNS-323, DNS-343