Now beginning to appear in the marketplace however is the first generation of PC hard drives having a larger sector size than 512 bytes. These drives are commonly called Advanced Format drives, and they have physical sectors of size 4096 bytes. This eight-fold increase in bit density has two main benefits:
- It allows for much higher hard drive capacity without requiring more platters in the hard drive.
- It improves error correction by allowing for use of longer ECC code words which can result in increased reliability for data transfers.
The problem however with increasing the number of bytes per physical sector like this is that key operating system components such as file system drivers and backup utilities have historically been optimized to work with 512 byte sectors. As a result, simply changing bytes per sector from 512 to 4096 may cause some of these components to fail to work properly or become unreliable in their operation. Advanced Format solves this problem through emulation—the hard drive interface "translates" each 4096 byte physical sector into eight 512 byte logical sectors. Because of this emulation, Advanced Format drivers are sometimes called 512e drives (the "e" stands for "emulation").
