longer correspond to their namesakes in modern disk drives, as well as being irrelevant in other devices such as solid-state drives, which do not physically have cylinders or heads.

In the CHS scheme, sector indices have (almost) always begun with sector 1 rather than sector 0 by convention, and due to an error in all versions of MS-DOS/PC DOS up to including 7.10, the number of heads is generally limited to 255 instead of 256. When a CHS address is too large to fit into these fields, the tuple