A method and apparatus for reverting a disk drive to an earlier point in time is disclosed. Changes made to the drive are saved in a circular history buffer which includes the old data, the time it was replaced by new data, and the original location of the data. The circular history buffer may also be implemented by saving new data elements into new locations and leaving the old data elements in their original locations. References to the new data elements are mapped to the new location. The disk drive is reverted to an earlier point in time by replacing the new data elements with the original data elements retrieved from the history buffer, or in the case of the other embodiment, reads to the disk are mapped to the old data elements stilled stored in their original locations. The method and apparatus may be implemented as part of an operating system, or as a separate program, or in the controller for the disk drive. The method and apparatus are applicable to other forms of data storage as well. Also disclosed are method and apparatus for providing firewall protection to data in a data storage medium of a computer system.
This application is a Continuation of application Ser. No. 09/105,733, filed Jun. 26, 1998, now U.S. Pat. No. 6,016,553, which is a Continuation-in-Part of application Ser. No. 09/039,650, filed Mar. 16, 1998, which is a Continuation-in-Part of application Ser. No. 08/924,198, filed Sep. 5, 1997 (now abandoned), which applications are made a part hereof.
Continuation Data
This application is a continuation-in-part of U.S. application Ser. No. 09/039,650, filed Mar. 16, 1998 and entitled "Method, Software And Apparatus For Saving, Using And Recovering Data", which is a continuation in part of Ser. No. 08/924,198, filed Sep. 5, 1997 entitled "Method and Apparatus for Saving and Recovering Data", the entire disclosures of which are hereby incorporated by reference herein.
A method and apparatus for storing multimedia data for use in a digital VCR includes processing that begins by maintaining a first link list of a plurality of memory sections, where the first link list links the plurality of memory sections as a circular buffer. The processing then continues by receiving a stream of multimedia data. The processing then continues by storing the stream of multimedia data in at least some of the memory sections of the plurality of memory sections. The processing then continues by receiving a request for independent storage of a selected portion of the stream of multimedia data, e.g., the user desires to have a permanent copy of a particular program. The processing further continues by generating a second link list for a set of memory sections of the at least some of the memory sections. The set of memory sections stores the selected portion of the stream of multimedia data. The processing continues by updating the linking of the plurality of memory sections within the first link list without the set of memory section.
The invention is a storage device (1) for a host computer system. The device (1) incorporates a Supervisor function for controlling access to information stored in a storage medium (2) of the device. The main embodiment described is a hard disk drive (1) comprising: one or more disk platters (2) for storing information; a ROM (4) for storing firmware for controlling operation of the drive; a volatile RAM (5); a micro-controller (7) for controlling the transfer of information to and from the disk platter(s) (2); and an interface (6) for interfacing the drive (1) with the host computer system and via which information is transferred to and from the disk platter(s) (2) under the control of the micro-controller (7). A Supervisor is provided in the form of firmware which is preferably stored in the ROM (4), the Supervisor operating the micro-controller (7) so as to protect information stored on the disk platter(s).
An image finder method and apparatus are provided for identifying a source image data file in a database based upon a printed image actually generated from a source image data file in the database. Input image data that represent a printed input image are received from a scanner. Source image data are received from the database that is defined by a plurality of different source image data files stored on a CD-ROM or other storage medium. Correlation operations are carried out to identify any source image data files that are highly correlated with the input image data. The results of the correlation operations are used to identify the source image data file from which the input printed image was actually generated or, if this is not possible, to identify more than one source image data file that could be the source image data file from which the printed input image was actually generated. Both the input image data and source image data are severely subsampled to obtain no more than about 1000 (and most preferably no more than 200) data values from each set of data for use in the correlation operation to provide for extremely fast processing without loss of accuracy.
Execution time performance of one or more applications that are dynamically loaded for execution post initial loading is improved by invoking selected parts of the one or more applications for execution post initial loading to allow disk locations accessed and the order the disk locations are accessed to load the selected parts of the one or more applications for execution post initial loading to be traced, and in turn, based at least in part on the order the disk locations are accessed, alternate disk locations to be identified to store the selected parts of the one or more applications to reduce time required to load the selected parts of the one or more applications for execution post initial loading.
A system for generating a virtual point-in-time copy of a selected subset (e.g., a selected volume or logical unit) of a storage system. The present system operates by using a bitmap in storage system controller cache memory to indicate blocks of memory in the selected volume that have been overwritten since the snapshot was initiated. When a write to the selected volume is requested, the cache bitmap is checked to determine whether the original data (in the area to be overwritten) has already been copied from the selected volume to a temporary volume. If the original data was previously copied, then the write proceeds to the selected volume. If, however, the original data would be overwritten by the presently requested write operation, then an area containing the original data is copied from the selected volume to a temporary volume. Reads from the temporary volume first check the bitmap to determine if the requested data has already been copied from the selected volume to the temporary volume. If so, the data is read from the temporary volume, otherwise, the data is read from the selected volume.
