Abstract: A data recording disk drive has a plurality of servo sectors containing error-detectable and error-correctable servo timing marks (STMs). Each STM is represented as a pattern of n bits of digital information, with each track having a set of m unique STM patterns, and wherein each of the m unique STM patterns of n bits has a minimum sliding distance d to every other STM pattern in the set, where d is greater than one. The error-tolerant STMs are achieved by the use of a set or code of fixed STM bit patterns, where the STM patterns have a specified minimum Hamming distance against all the patterns in the search, called the sliding distance d. These STM patterns may include any bits associated with the servo sectors, such as bits indicating track index, servo sector number, and recording head number.

Abstract: A magnetic recording disk drive uses side-by-side read/write heads formed on head carriers that are identical for both top and bottom disk surfaces. Thus, a common head carrier functions as a single manufacturable part usable for both top and bottom disk surfaces. The common head carrier has a trailing end with a pattern of components formed on it that includes three side-by-side transducers (two read elements equally spaced about a center write element) and five terminal pads, one of which is a common pad, and all of the electrical connectors interconnecting the five terminal pads with the three transducers. There are only three terminal pads for the two read elements, with one of the read terminal pads being a common terminal pad that is electrically connected to both read elements. During assembly of the disk drive, the common carrier, when used as the top carrier, has a first read terminal pad and the common terminal pad connected to the leads on the suspension.

Abstract: A magnetic recording disk drive uses side-by-side read/write heads formed on head carriers that are substantially identical for both top and bottom disk surfaces. Thus, a common head carrier functions as a single manufacturable part usable for both top and bottom disk surfaces. The common head carrier has a trailing end with a pattern of components formed on it that includes three side-by-side transducers and sets of terminal pads. In the read/write/read side-by-side head arrangement, the first element is a center write element, such as an inductive coil, and the second and third elements are read elements, such as magnetoresistive read elements, that are generally equally spaced from the center write element.

Abstract: A zoned recording, embedded servo disk drive includes a sector architecture in which the recording head locates and identifies data sectors without using data identification (ID) fields, but instead using information obtained from electronic storage and from servo sectors which need not be adjacent to the data sectors. Each data track contains servo information and data, but not data sector ID information, and is circumferentially divided into identical segments. Included in each track segment is a number of data regions separated from one another by servo sectors. The data regions in each track segment may contain partial data sectors and complete data sectors, and each data sector is identified by a number indicating its location relative to the beginning of the track segment.

Abstract: A gray code is provided for use with disk servo track identification encodement that preserves the gray code property of only a single digit changing state between two numbers in the code sequence and also preserves magnetization between code numbers while only requiring a single bit for encoding each code value by recording a single pad bit before the gray code bits. By proper selection of the sign of the pad bit and the gray code numbering sequence, the gray code encodement scheme uses n+1 code bits for an n-bit gray code. The efficiency of the gray code encodement can be enhanced by splitting the track identification number to be recorded into multiple fields and then recording only the low order bits sufficient to identify a track within the maximum estimated error of the servo head on every track and otherwise alternating the high and low middle order bit fields with the low order bit field. A run-length limiting feature also can be provided.

Abstract: A data recording disk drive for use in a portable, battery-powered computer has several power-save modes of operation. The power-save modes are entered after a computed time since the last data read or write command. The computed time to enter a power-save mode is based on the computer user's real-time workload and is thus continuously varying during operation of the disk drive. The disk drive detects the current user workload by calculating the frequency of disk drive accesses and based on this history determines which of a plurality of power-save modes is appropriate and when to enter a power-save mode. Each disk drive read or write access is detected and used to compute a current access frequency. The current access frequency is compared to a previously calculated and continuously updated threshold frequency. The threshold frequency is representative of the access pattern, e.g., uniform or sporadic, and is computed from equations that include adjustable gain factors.