Circuit and method for maintaining a rotation position reference on a disc drive with a staggered servo format
AssigneeSeagate Technology LLC
InventorStephen C. Tigner
Life of this patent
Estimating the term…
Abstract
A data storage apparatus is provided in which the multiple disc surfaces for a disc stack are divided into multiple rotationally spaced apart servo frames. Servo data is written on the multiple disc surfaces within radially extending servo spokes such that each disc surface includes one servo spoke within each servo frame. Within each particular servo frame the servo spokes on each of the multiple disc surfaces are offset rotationally from one another. In addition, servo control circuitry and a method of using the same to provide positional reference signals for the staggered servo format are disclosed.
Claims18
A headerless format disc drive comprising:
- a disc stack including a plurality of coaxially arranged data storage discs providing a plurality of disc surfaces, wherein a plurality of rotationally spaced apart servo frames are defined for the disc stack;
- servo data written on the plurality of disc surfaces within radially extending servo spokes such that each disc surface includes one servo spoke within each servo frame, and such that within each paticular servo frame the servo spokes on each of the plurality of disc surfaces are offset rotationally from one another;
- a plurality of data heads, wherein each of the plurality of data heads is supported by an actuator assembly adjacent a corresponding one of the plurality of disc surfaces, wherein a selected first of the plurality of data heads reads data from its corresponding disc surface until a head switch occurs, and wherein after the head switch occurs a selected second of the plurality of data heads reads data from its corresponding dics surface;
- and
- control circuitry operatively coupled to the plurality of data heads and receiving the data read by the selected first data head, and after the head switch receiving the data read by the selected second data head, the control circuitry generating as a first output a first signal which is indicative of boundaries of the respective servo frames.
A method of generating servo reference signals using servo control circuitry of a disc drive, the disc drive including a plurality of coaxially arranged data storage discs providing a plurality of disc surfaces having a plurality of rotationally spaced apart servo frames defined thereon, the disc drive also including servo data written on the plurality of disc surfaces within radially extending servo spokes such that each disc surface includes only one servo spoke within each servo frame, and such that within each particular servo frame the servo spokes on each of the plurality of disc surfaces are of set rotationally from one another, the method comprising:
- (a) receiving first signals, corresponding to data read from a first disc surface using a first data head, until a first head switch occurs;
- (b) after the head switch occurs, receiving second signals corresponding to data read from a second disc surface using a second data head;
- and
- (c) generating servo reference signals as a function of the received first and second signals.
Dependencies are inferred from the claim text.