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US 2001/0011331 A1Published application
Controlling shared disk data in a duplexed computer unit
AssigneeNokia Telecommunications Oy
InventorPEKKA KOIVUNIEMI
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AssigneeNokia Telecommunications Oy
InventorPEKKA KOIVUNIEMI
Estimating the term…
In fault-tolerant systems it is known to write data into two separate disk drives. It is also known to duplex computers so that when one computer fails, the other computer can continue operating. In such a system, the active unit usually controls both disk drives. It is also known to cache in the main memory of the computer the most recently used areas in the disk drive, since it is likely that these areas (e.g. directories) must be read again soon. A problem occurs when using duplexed computers each of which is to be provided with a possibility of using the disk drive (14, 24) while the operation is expedited by caching in the main memories of the computers (10, 20). If one computer modifies the data in the disk drive, the other computer is not necessarily aware of this, but it uses the outdated data in its memory. According to the invention, the computer (10) desiring to control the disk drive (14) reserves it for itself. If the reservation is successful, a disk talk is performed. If the data in the disk drive (14) is changed, the other computer (20) is informed of this change and it erases from its memory the cached data corresponding to the changed data.
A method of controlling a shared disk drive (14) in a system comprising at least two computers (10, 20), a shared disk drive (14), and a disk drive bus (15) connecting the computers (10, 20) and the disk drive (14), in which method the first computer (10) using the shared disk drive (14):
A system for controlling a shared disk drive (14) from two computers (10, 20) at least one (10) of which comprises a memory (12) for buffering the data in the disk drive (14), the system also comprising a disk drive bus (15) connecting the computers (10, 20), and a disk drive (14), and disk management software comprising the following functions:
Dependencies are inferred from the claim text.