Data placement variation compensation system

Abstract

The invention comprises a magnetic disk storage system and comprises method for configuring the magnetic disk storage system. The magnetic disk storage system facilitates write and read operations that compensate for variances that are experienced with magnetic disk storage systems. When writing data to a data sector, the magnetic disk storage system utilizes a phase lock oscillator field that has a length that is specified for that data sector. When reading from a data sector, the magnetic disk storage system utilizes an incremental read delay that has a duration that is specified for that data sector. Data sectors with shorter data sector delay periods can have shorter phase lock oscillator fields than data sectors with larger data sector delay periods. This frees-up memory space and increases the capacity and performance of the magnetic disk storage system.

1. A magnetic disk storage system that comprises at least one data sector on a magnetic disk device, wherein the system comprises:
 a control means for specifying a length of a phase lock oscillator field for the data sector based on a data sector delay period for the data sector; and  
 a writing means for writing a set of data to the data sector, wherein the set of data includes the phase lock oscillator field having the length specified by the control means.  
 
     
     
       2. The system of  claim 1  wherein the system comprises multiple data sectors on the magnetic disk and wherein the control means specifies each individual length of each individual phase lock oscillator field for each individual data sector based on a data sector delay period for the individual data sector. 
     
     
       3. The system of  claim 1  wherein the control means is further for specifying a duration of an incremental read delay for the data sector based on the data sector delay period for the data sector, and wherein the system further comprises:
 a reading means for reading the set of data from the data sector after the incremental read delay plus the data sector delay period, wherein the incremental read delay has the duration specified by the control means.  
 
     
     
       4. The system of  claim 3  wherein the system comprises multiple data sectors on the magnetic disk and wherein the control means specifies each individual duration of each individual incremental read delay for each individual data sector based on a data sector delay period for the individual data sector. 
     
     
       5. The system of  claim 3  wherein the data sector delay period is a time period from when the system detects a timing reference on the magnetic disk device until the magnetic disk device is positioned to write to the data sector. 
     
     
       6. The system of  claim 3  wherein the control means is incorporated into a logic circuit in a hard disk controller. 
     
     
       7. The system of  claim 3  wherein the control means comprises a memory that associates the data sector with information incorporating the length of the phase lock oscillator field for the data sector and with information incorporating the duration of the incremental read delay for the data sector. 
     
     
       8. The system of  claim 7  wherein the memory is comprised of registers. 
     
     
       9. The system of  claim 7  wherein the memory is a first-in/first-out memory. 
     
     
       10. The system of  claim 7  wherein the memory is on the magnetic disk device. 
     
     
       11. The system of  claim 3  wherein the timing reference is a servo timing mark. 
     
     
       12. The system of  claim 3  wherein the control means is further for specifying the length of the phase lock oscillator field and the duration of the incremental read delay based on a variance in the system. 
     
     
       13. The system of  claim 12  wherein the variance comprises a variance in magnetic disk device spin speed. 
     
     
       14. The system of  claim 12  wherein the variance comprises a variance in timing clock frequency. 
     
     
       15. The system of  claim 12  wherein the variance comprises a variance in detection of the a timing reference versus a timing clock phase. 
     
     
       16. A method for configuring a magnetic disk storage system that has at least one data sector, the method comprising:
 configuring the system to specify a length of a phase lock oscillator field for the data sector based on a data sector delay period for the data sector; and  
 configuring the system to write a set of data to the data sector, wherein the set of data includes the phase lock oscillator field having the length specified by the control means.  
 
     
     
       17. The method of  claim 16  wherein the system comprises multiple data sectors on the magnetic disk and further comprising configuring the system to specify each individual length of each individual phase lock oscillator field for each individual data sector based on a data sector delay period for the individual data sector. 
     
     
       18. The method of  claim 16  further comprising configuring the system to specify a duration of an incremental read delay for the data sector based on the data sector delay period for the data sector, and to read the set of data from the data sector after the incremental read delay plus the data sector delay period, wherein the incremental read delay has the duration specified by the control means. 
     
     
       19. The method of  claim 18  wherein the system comprises multiple data sectors on the magnetic disk and further comprising configuring the system to specify each individual duration of each individual incremental read delay field for each individual data sector based on the data sector delay period for the individual data sector. 
     
     
       20. The method of  claim 18  further comprising configuring a logic circuit in a hard disk controller in the system. 
     
     
       21. The method of  claim 18  further comprising configuring the system with a memory that associates the data sector with information incorporating the length of the phase lock oscillator field for the data sector and with information incorporating the duration of the incremental read delay for the data sector. 
     
     
       22. The method of  claim 18  further comprising configuring the system to specify the length of the phase lock oscillator field and the duration of the incremental read delay based on a variance in the system. 
     
     
       23. The method of  claim 22  wherein the variance comprises a variance in magnetic disk device spin speed. 
     
     
       24. The method of  claim 22  wherein the variance comprises a variance in timing clock frequency. 
     
     
       25. The method of  claim 22  wherein the variance comprises a variance in detection of the a timing reference versus a timing clock phase. 
     
     
       26. A method, comprising:
   detecting a time reference on a data - storage disk having a data sector; and        reading the data sector a delay time after detecting the time reference, the delay time equal to the sum of an incremental read delay and a data - sector delay period for the data sector, the incremental read delay being related to the data - sector delay period.     
     
     
       27. The method of  claim 26  wherein reading the data sector comprises reading a phase- lock oscillator field having a length that is proportional to the data - sector delay period.   
     
     
       28. The method of  claim 26  wherein reading the data sector comprises reading a phase- lock oscillator field having a length that is proportional to the incremental read delay.   
     
     
       29. The method of  claim 26  wherein the incremental read delay is proportional to the data- sector delay period.   
     
     
       30. The method of  claim 26  wherein reading the data sector comprises:
   waiting the data - sector delay period after detecting the time reference;        waiting the incremental read delay after the data - sector delay period has elapsed; and        reading the data sector after the incremental read delay has elapsed.     
     
     
       31. A method, comprising:
   determining a duration of a data - sector delay period for a data sector of a data - storage disk; and        calculating a duration of an incremental read delay for the data sector based on the duration of the data - sector delay period.     
     
     
       32. The method of  claim 31  wherein determining the duration of the data- sector delay period comprises measuring a time between a timing reference on the data - storage disk and a beginning of the data sector.   
     
     
       33. The method of  claim 31  wherein determining the duration of the data- sector delay period comprises selecting the duration of the data - sector delay period.   
     
     
       34. The method of  claim 31  wherein calculating the duration of the incremental read delay comprises calculating the duration of the incremental read delay to be proportional to the duration of the data- sector delay period.   
     
     
       35. A method, comprising:
   determining a duration of a data - sector delay period for a data sector of a data - storage disk; and        calculating a length of a phase - lock oscillator field for the data sector based on the duration of the data - sector delay period.     
     
     
       36. The method of  claim 35  wherein calculating the length of the phase- lock oscillator field comprises calculating the length of the phase - lock oscillator field to be proportional to the duration of the data - sector delay period.   
     
     
       37. A method, comprising:
   detecting a timing reference on a data - storage disk;        waiting a data - sector delay period after detecting the timing reference; and        writing a phase - lock oscillator field in the data sector after the data - sector delay period has elapsed, the phase - lock oscillator field having a length that is related to the data - sector delay period.