Optimizing data transfer performance through partial write command purging in a disc drive

In a data storage device a method comprising:

• identifying a phase time as an elapsed time to configure a data storage device for servicing each of a plurality of access commands received from a host device;
• determining whether a thread can be formed between a first write command of said access commands associated with a first set of blocks of write data and a second write command of said access commands associated with a second set of blocks of write data, wherein said thread can be formed when an elapsed time between the completion of the storage of the first set of blocks of write data and the beginning of the storage of the second set of blocks of write data is less than a preselected phase interval;
• when no thread is formed, executing a selected access command having the minimum phase time as determined;
• and
• when a thread is formed, executing the thread so that the first and second write commands are serviced in lieu of the selected access command having the minimum phase time.

A disc drive data storage device configured to store and retrieve data from a host device, comprising:

• a data transducing head controllably positionable adjacent a data recording surface on which data are stored;
• an interface circuit coupled to the head and the host device and comprising a data buffer to temporarily store data being transferred between the data recording surface and the host device, wherein the interface circuit receives and places in a command queue access commands from the host device including read commands identifying read data to be retrieved to the host device and write commands identifying write data to be stored by the data storage device;
• and
• a control processor coupled to the interface circuit which directs execution of a number of pending access commands in the command queue by the interface circuit by:
• identifying a phase time for each access command as an elapsed time to configure the data storage device to initiate servicing of the access command;
• when the total amount of write data in the buffer is below a first selected threshold, executing the access commands in an order selected in relation to the identified phase times;
• and
• when the total amount of write data in the buffer is above the first selected threshold, determining an intermediary phase interval between the completion of each write command in the command queue and the start of each remaining write command in the command queue, identifying a thread of write commands having an associated intermediary phase interval less than a predetermined phase interval level, and executing the thread of write commands in lieu of another read or write command having a smaller phase time.

A disc drive data storage device configured to store and retrieve data from a host device, comprising:

• a data transducing head controllably positionable adjacent a data recording surface on which data are stored;
• an interface circuit coupled to the head and the host device and comprising a data buffer to temporarily store data being transferred between the data recording surface and the host device, wherein the interface circuit receives access commands from the host device including read commands identifying read data to be retrieved to the host device and write commands identifying write data to be stored by the data storage device;
• and
• first means for directing execution of a number of pending access commands by the interface circuit to obtain an increased data transfer rate and to limit accumulation of write data in the buffer.