Method and apparatus for determining the logic and functionality of a changeline
US5625799A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 29, 1994 |
| Grant date | Apr 29, 1997 |
| Priority date | — |
| Expiry date | Jun 29, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F11/2221
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for determining the logic and functionality of a disk changeline. By attempting to reset the changeline and monitoring the changeline for a change in state, the present invention determines whether a changeline is functional. When the present invention does not immediately observe a change in state, the present invention accesses the disk drive to determine whether a disk is present in the drive. When a disk is present in the drive, the present invention reads the changeline and stores the read value as a disk present value. When the present invention has previously determined that the changeline is functional, the present invention inverts the disk present value to create a disk not present value. When a disk is not present in the disk drive, the present invention stores the read value of the changeline as the disk not present value. Having obtained a disk not present value, the present invention compares the obtained value with a known active changeline state of a machine using an inverted logic. When the disk not present value is not equivalent to the active changeline value of the inverted logic machine, the present invention determines that the changelin…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.