Advanced Format

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The Technology

Hard drive manufacturers have moved to a new standard: 4KB (4,096 bytes) sectors, replacing 512B sectors. This is a good thing; it means that the signal-to-noise ratio improves, and less space is needed for error correction. Long-term improvements in speed, density, and overall capacity. Western Digital has started releasing drives with 4KB sectors under the name "Advanced Format" (not to be confused with the Advanced Forensics Format).

The Standard

ATA 7 (T13/D1532, INCITS 397-2005) introduced Long Physical Sector (LPS) and Long Logical Sector (LLS) feature sets. Drives with large sector sizes shall report the actual physical/logical size in words 106 and 117-118 of the ATA IDENTIFY data.

Some Western Digital drives with "Advanced Format" reportedly do not provide the information about physical sector size (see External Links).

The Problem: Death of LBA 63

Operating systems written before the transition, particularly XP, have trouble with the new drives. XP makes an assumption about where the format should start (LBA 63), but this doesn't work well with the translation software that maps from logical 512B blocks to physical 4K blocks.

The nutshell is that XP should not be used to format these drives, and some assumptions made by tools and users need to be corrected. For analysis purposes, note that you can't assume that an NTFS partition starts at LBA 63. If you are used to using, for example, the Sleuthkit command "fls -o 63 <image>", this may need to change. Hopefully more information about these drives will come forth as time progresses.

The Solution

To format one of these drives properly for Windows XP, use the following utility (this applies only to drives from Western Digital):

Western Digital Advanced Drive Format Utility

External Links