Disk drive with adaptive pooling for command reordering
US6145052A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 4, 1997 |
| Grant date | Nov 7, 2000 |
| Priority date | — |
| Expiry date | Nov 4, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B19/02
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method for selecting a next command to execute from a set of SCSI commands where the commands are gracefully aged and performance of a disk drive is improved. An execution threshold age, a pool threshold age, and an age threshold age are used to determine what command is executed next. A mechanical time delay is calculated for a command based on the time required to position the read/write head over the data location requested in each command. A command age is calculated based on a current time and the time the command was received from the host. The command age is checked against the execution threshold age and pool threshold age. Any commands that have aged beyond the execution threshold age are executed. If the oldest command has aged beyond the age threshold age, then any command that has both aged beyond the pool threshold age and has the smallest mechanical time delay is executed, otherwise the command with the smallest mechanical time delay is executed. Alternatively, a time stamp of the oldest command is compared against an age threshold to determine if all or some of the commands are in the pool of commands. If there are no commands that have aged beyond the age threshol…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.