Conflict detection for queued command handling in disk drive controller
US6490635B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Apr 28, 2000 |
| Grant date | Dec 3, 2002 |
| Priority date | — |
| Expiry date | Apr 28, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F3/0676
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A conflict detection method for a disk drive controller is used to handle a conflict potentially occurring if the execution sequence of queued commands sent from a host to a controller is reordered to optimize disk drive transfers. The conflict detection method determines if there is an address range overlap between two queued commands. If an overlap exists, a conflict flag is set. The controller microprocessor utilizes this flag to restrict command reordering and prevent a conflict from producing erroneous data. Conflict detection and command reordering restriction are facilitated by a queued command RAM and a command FIFO. The queued command RAM stores command parameters indexed by command tag values. These parameters include command direction (read or write), LBA, block count, a valid flag and a conflict flag. The conflict detection method compares the address range of a new command with the address range of valid commands in the command RAM to determine range overlaps. If an overlap exists with a new write command, the conflict flag is set for both the write command and the overlapping commands in the queued command RAM. The microprocessor accesses the queued command RAM to det…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.