System and method for utilizing the memory of a portable computer as a disk cache while in SCSI target mode
AssigneeApple Computer, Inc.
InventorsHerbert G. Derby, Cameron J. Esfahani, David R. Falkenburg
Life of this patent
Estimating the term…
Abstract
A system and method for increasing the speed and resource utilization of a computer system in which a personal computer uses a portable computer as an extra hard disk. While the portable computer is in SCSI target mode, the unused memory of the portable computer is converted into a disk cache for the hard disk of the portable computer. This enables the portable computer to perform as a very fast disk.
Claims30
A computer system comprising:
- a first computer;
- a second computer coupled to the first computer, the second computer including a memory and a hard disk, the second computer for performing data accesses by storing data from the first computer into the hard disk and by transferring requested data from the hard disk to the first computer to extend the storage capacity of the first computer;
- and
- control program means for controlling conversion of the memory into a disk cache to act as a high speed buffer, thereby reducing the response time of the computer system during the data accesses of the hard disk by the first computer.
A method for converting a memory of a second computer into a cache in a computer system in which a first computer stores data in a hard disk of the second computer and requests data from the hard disk, the first computer communicating with the second computer using a first type of commands, the method comprising the steps of:
- (a) receiving the first type of commands from the first computer;
- (b) determining if requested data is stored in the memory;
- (c) fetching the requested data from the memory when the requested data is the memory;
- (d) when the requested data is not in the memory,
- (d1) fetching the requested data from the hard disk, and
- (d2) storing the requested data into the memory;
- and
- (e) sending the requested data to the first computer, whereby the second computer performs as a fast disk and extends the storage capacity of the first computer.
A computer readable medium containing program instructions for converting a memory of a second computer into a cache in a computer system in which a first computer stores data in a hard disk of the second computer and requests data from the hard disk, the first computer communicating with the second computer using a first type of commands, the program instructions for:
- (a) receiving the first type of commands from the first computer;
- (b) determining if requested data is stored in the memory;
- (c) fetching the requested data from the memory when the requested data is the memory;
- (d) when the requested data is not in the memory,
- (d1) fetching the requested data from the hard disk, and
- (d2) storing the requested data into the memory;
- and
- (e) sending the requested data to the first computer, whereby the second computer performs as a fast disk and extends the storage capacity of the first computer.
A computer system comprising:
- a bus;
- a personal computer;
- a portable computer coupled to the personal computer via the bus, the portable computer including a hard disk, the portable computer being placed in a first mode for performing data accesses by storing data from the personal computer into the hard disk and by transferring requested data from the hard disk to the personal computer to extend the storage capacity of the first computer;
- and
- memory means for serving as a cache for the hard disk of the portable computer to act as a high speed buffer, thereby decreasing the response time of the portable computer during the data accesses of the hard disk by the first computer.
Dependencies are inferred from the claim text.