An apparatus and method for disk sector layout, formatting, reading and writing, is based on a flexible formatter microengine that is driven by parameter lists, which may include commands to dynamically download the microengine's writable control store during disk access operations. This reduces the intervention required by the local microprocessor to support exception handling, including defect management, thus decreasing total access time for typical disk access (format, write or read) operations. This also reduces or eliminates the area on the disk required for ID fields, thus increasing the storage capacity of disk drives controlled by the present invention. This also increases disk space utilization, thus increasing the storage capacity of a disk drive controlled by using the present invention. Additionally, the invention is based on ID fields that may contain redundant information for increased fault tolerance. Additionally, the invention supports split data fields while minimizing the amount of additional information that the ID fields must contain about the data field split sizes. Alternatively, the invention supports eliminating ID fields entirely with the prior art functions of ID fields taken over by a combination of parameter lists and sector status flags.