摘要:
The invention (Fig. 6) is directed to a method for reading files stored on a storage system. The storage system comprises storage means (104) storing a first set of files according to a predetermined data format and a cache memory (106) storing a second set of files, the second set of files being a subset of the first set of files. The storage system is configured to allow one or more remote systems (110, 120) for reading files stored on the storage means and/or on the cache memory. The method comprises: - receiving (602) from one or more remote systems at least one read request for reading a sequence of files; - determining (604), among the files of the sequence, whether one or more cached files are already stored on the cache memory and whether one or more remaining files are not already stored on the cache memory; - determining (606), within said one or more remaining files, an order according to which said remaining files should be read on the storage system, given locations of said remaining files as stored on the storage system according to said predetermined data format; - reading (608) said one or more remaining files on the storage system according to said order and storing the remaining files on the cache memory.
摘要:
The invention relates to data storage system in which a virtual tape drive or disc drive is emulated and such tape or disc drive achieves data compression without any changes or modifications to the back up software thereby facilitating cost effectiveness and speed. The present invention enables the client to save network bandwidth and storage space.
摘要:
Descriptored information is stored in a file system according to a Uniform Disk Format Specification UDF. It accommodates storage of both data and descriptor items, through separating a descriptor item from the data through storing the former in a dedicated logical sector. In particular, the descriptor items are assigned to a dedicated and immediately accessible directory space. Within the directory space, successive logical sectors are mapped at mutual stepping distances that are a factor less than a physical sector size that is uniform among data and descriptor items.
摘要:
A changer having a security function. Tape cassettes are supplied to drives (102-1 - 102-p) selectively from a plurality of storage units of a cassette rack to write/read data. Information on the security preset for elements in a plurality of storage units of a media rack, drives, etc. is stored in a nonvolatile memory (114). When the security is set, a setting command is sent to a controller (110) from the outside and the information on the security, for instance, a host ID, a password, confidential information, information on a group of elements storing information secretly, is written in the memory (114). When the security is released, a release command is sent to the controller (110) from the outside and the information on the security is erased from the memory (114). When a command from a host computer is executed, the controller (110) refers to the information on the security which is stored in the memory (114) and controls the execution of the command to maintain the security.
摘要:
A magnetic tape (22) is formatted to be interchangeably usable by a plurality of types of devices, including an audio/visual recording/reproducing device (14), a random access recording/reproducing device (16), and a sequential access recording/reproducing device (18). The tape has frames (22) of a plurality of frame types, including control frames and user frames. Each frame has an AUX data structure (300) wherein resides a field which indicates the frame type of the frame. Selected ones of a plurality of control tables or frames (340, 342, 344, 346, 348) are present on the tape in accordance with the type of data recorded on the tape (e.g., audio/visual data and non-audio/visual data) and the particular types of devices which are to utilize the tape. The user frames of the tape have a field in the AUX data structure which specifies the nature of the data therein, e.g., as general purpose data or audio/visual data. The tape has a permanently embedded servo format whereby each of the frames are hard sectored with a permanent physical relationship to the tape.
摘要:
A magnetic tape drive (40) includes a write transfer channel and a read transfer channel which cause head(s) (100) to transduce data between the drive and a tape (32) at a transfer channel data rate. Relative motion of the tape and the head(s) occurs at a transport rate so that tracks are recorded on or reproduced from the tape. A tape speed controller (133) and variable clock controller (134) dynamically adjust the transfer channel data rate in accordance with the transport rate. Thus the recording of data on the tape and reading of data from the tape occurs at a rate which is related to the linear velocity of the tape.