"If you're familiar with disk structure, you know that disks are
broken down into sectors, which are normally 512 bytes in size; all
read or write operations occur in multiples of the sector size.
When you look closer, hard disks actually include a great deal of
extra data in between sectors. These extra bytes are used by the
disk's firmware to detect and correct errors within each sector. As
hard disks grow larger, the result is that more and more data must
be stored on each square centimeter of disk, resulting in more
low-level errors, thus straining the firmware's error correction
"One way around this problem is to increase the sector size from
512 bytes to a larger value, enabling more powerful
error-correction algorithms to be used. These algorithms can use
less data on a per-byte basis to correct for more serious problems
than is possible with 512-byte sectors. Thus, changing to a larger
sector size has two practical benefits: improved reliability and
greater disk capacity—at least in theory.
"The real-world benefits to end users aren't likely to be
obvious in the same way that an increased monitor size or improved
central processing unit (CPU) speed are obvious. However, the
reduction in space devoted to parity may result in quicker
introduction of larger disks or better disk reliability."