Abstract: A method for improving seed germination efficiency by reducing seedling loss caused by desiccation, temperature extremes, wind and water displacement, and consumption by animal and insect predators. The method comprises covering the medium for the seed growth with a layer of material which allows light transmission and provides a thermal barrier, and in addition applies a compacting force which brings the seed in better contact with the growing medium. The material also provides a barrier to protect the seed from animal and insect predators. The layer of material used preferably consists of a clear plastic membrane supporting the presence of a sufficient amount of water to allow the transmission of light, provide a thermal barrier, compact the seeds to the growing medium, and deter access from animals and airborne insects. The technique is applicable to all forms and seed germination including grass and vegetable gardens.

Abstract: A system for controlling a towrope winch may comprise an electronic user interface selectively coupled to the towrope winch in which the user interface is configured to send and receive data to and from the towrope winch. A towrope winch user interface may comprise a processor configured to control said towrope winch, and a number of memory devices electrically coupled to the processor, in which the user interface is configured to send and receive data to and from the towrope winch. A mobile communications device may comprise a processor configured to control a towrope winch, a number of memory devices electrically coupled to the processor, and a tow system port configured to provide signal transfer between the processor and the towrope winch coupled to the mobile communications device, in which the mobile communications device is configured to send and receive data.

Abstract: Maintaining logically consistent backups using minimal data transfer. A backup, or snapshot, copy of original data is created and stored. A user designates data blocks that are to be backed up in a process of creating a subsequent snapshot copy of the data. Data blocks that are to be backed up might include those associated with active files having data of interest to the user. Data blocks that are not desired for backup might include, for example, swap files, printer buffers and temp files. The changes that have been made to the data blocks that have been designated for backup are applied to the snapshot copy after a specified time period has elapsed. Since only desired data blocks are backed up to the snapshot copy, memory, processing cycles and communication bandwidth are used more efficiently than if all data blocks were to be backed up to the snapshot copy.

Abstract: A method and system for mirroring and archiving mass storage. A primary mass storage and a secondary mass storage are synchronized to contain the same data. Thereafter, a primary system tracks changes made to the primary mass storage. These changes are consolidated periodically into update files, the consolidations representing changes made to the primary mass storage during a time interval that ends when the primary mass storage is in a logically consistent state. These update files contain only those changes necessary to represent the modified state of the primary mass storage at the time of the update. The primary system then transfers the update files to a secondary system to bring the secondary mass storage current with the primary mass storage. The consolidation minimizes the amount of information that must be transferred and therefore allows for a relatively low band width communication channel.

Abstract: Data blocks lost at a primary mass storage are restored while allowing the primary computer system to access the lost data block before full restoration. Restoration occurs along two channels. In the first channel, read requests issued by the primary computer system are handled by obtaining the requested data block from the backup mass storage device. The retrieved data block is then written to the primary mass storage, thereby restoring the primary mass storage for that data block. In the second channel of restoration, a snapshot copy of a selected data set of the backup mass storage is made and transported to the primary system. If the corresponding data block in the primary mass storage has a current data block, the data block is not written from the snapshot copy to the primary mass storage. Otherwise, the data block is copied from the snapshot copy to the primary mass storage.

Abstract: Recovering mirrored data after the failure of a computer using write requests stored in a delta queue of an associated computer without transmitting all of the mirrored data. A write request at a primary computer is stored in a delay buffer. A copy of the write request is transmitted to a backup computer and stored in a delta queue. The backup computer executes the copy of the write request and transmits acknowledgement of the receipt of the write request to the primary computer. In response to the acknowledgement, the primary computer executes the write request stored in the delay buffer. The computers then exchange subsequent acknowledgements of the write request execution, enabling the computers to delete the write requests. If the primary computer fails, the primary computer recovers data by receiving only the copies of write requests that remain stored in the delta queue of the backup computer.

Abstract: Recovering mirrored data after the failure of a computer using write requests stored in a delta queue of an associated computer without transmitting all of the mirrored data. A write request at a primary computer is stored in a delay buffer. A copy of the write request is transmitted to a backup computer and stored in a delta queue. The backup computer executes the copy of the write request and transmits acknowledgement of the receipt of the write request to the primary computer. In response to the acknowledgement, the primary computer executes the write request stored in the delay buffer. The computers then exchange subsequent acknowledgements of the write request execution, enabling the computers to delete the write requests. If the primary computer fails, the primary computer recovers data by receiving only the copies of write requests that remain stored in the delta queue of the backup computer.

Abstract: Obtaining mirrored data so that the original data can be recovered after failure without transmitting the entire mirrored data between computers. A write request at a primary computer is stored in a delay buffer and a copy is transmitted to a backup computer, where it is stored in a delta queue. The backup computer executes the copy of the write request to the mirrored data and transmits an acknowledgement to the primary computer that the copy of the write request has been received. In response to the acknowledgement, the primary computer executes the write request stored in the delay buffer. The computers send to each other subsequent acknowledgements of the write request execution, enabling the computers to delete the write requests. If the primary computer fails, the primary computer can recover the original data by receiving only the copies of write requests that remain stored in the delta queue.

Abstract: Obtaining mirrored data so that the original data can be recovered after failure without transmitting the entire mirrored data between computers. A write request at a primary computer is stored in a delay buffer and a copy is transmitted to a backup computer, where it is stored in a delta queue. The backup computer executes the copy of the write request to the mirrored data and transmits an acknowledgement to the primary computer that the copy of the write request has been received. In response to the acknowledgement, the primary computer executes the write request stored in the delay buffer. The computers send to each other subsequent acknowledgements of the write request execution, enabling the computers to delete the write requests. If the primary computer fails, the primary computer can recover the original data by receiving only the copies of write requests that remain stored in the delta queue.

Abstract: A primary computer system and a backup computer system each have an associated memory. For each write request, a copy of the request is forwarded to a delay buffer and memory queue associated with the primary computer system, and a copy is forwarded to a memory queue of the backup computer system. The backup computer system transmits an acknowledgement signal to the primary computer system when the backup computer system receives its copy of the request. The write request in the delay buffer of the primary computer system is executed in the primary memory only upon receipt of this acknowledgement signal. Thus, the backup computer system knows of every request executed in the primary memory. The write request is executed in the backup memory at any time after the backup computer system receives the write request.

Abstract: A system and method for comparing mass storage devices. Generally, a mass storage device is subdivided into data blocks representing physical storage locations of some particular size. For each one (or group) of data block(s), a digest is calculated, wherein the digest is an alternate representation of the data stored within the data block(s). A digest is highly dependent on the data it represents such that different data is extremely likely to result in different digests. This high dependence allows for comparing digests rather than directly comparing the data stored at each data block. Furthermore, by calculating a digest that requires fewer bits than the data block(s) it represents, the amount of data that must be transferred between mass storage devices during comparison is minimized.

Abstract: A system and method for using a virtual device established at a computer system to access data as it existed at a selected moment in a mass storage system associated with the computer system, regardless of whether new data has been written to the mass storage system. When an original data block is to be overwritten in the mass storage system with a new data block, the original data block is first preserved in a preservation memory associated with the computer system. The preservation memory thereby preserves the original data block as it existed at the selected moment. A virtual device established at the computer system provides access to data as it existed at the selected moment. This data may include original data blocks preserved in the preservation memory and other original data blocks that remain in the mass storage device, and which have not been overwritten with new data.

Abstract: A system and method for maintaining logically consistent backups using minimal data transfer are presented. A system comprises a backup system having a backup storage device and one or more primary systems having mass storage devices that are to be backed up on the backup storage device. The primary systems identify changes that are going to be made to the mass storage device. The combined effected locations in the mass storage device of these identified changes are then captured in a static snapshot when the mass storage device is in a logically consistent state. Only those data blocks changed since the last backup are then transferred to backup system. The backup system can then store these changes or apply the changes to the backup storage device in order to bring the backup storage device current to a particular point in time.