A compression device recognizes patterns of data and compressing the data, and sends the compressed data to a decompression device that identifies a cached version of the data to decompress the data. In this way, the compression device need not resend high bandwidth traffic over the network. Both the compression device and the decompression device cache the data in packets they receive. Each device has a disk, on which each device writes the data in the same order. The compression device looks f...

In inputting control information for setting access conditions in a system having a common data bus (3), when a predetermined bit string making up an access condition setting command is inputted to predetermined terminals which are not data input/output terminals (S3), the predetermined terminals are set as control information input terminals (S5) and inputted control information is temporarily maintained in a non-volatile memory device (S13). When inputting of control information is completed (...

It has been impossible in prior art to copy every piece of data that is stored in a virtual volume. A management computer of this invention receives a copy request that designates a real storage area as a copy source, selects a virtual storage area that is associated with plural real storage areas as a copy destination virtual storage area, and judges whether or not a copy source virtual storage area and the copy destination virtual storage area are allocated to real storage areas. Based on a re...

The enclosure 10 in which the storage control system 600 is constructed comprises a scale-out NAS head group 111 constituted by two or more NAS heads, and a scale-up NAS head 110H that is a higher performance NAS head than each of NAS head members 110L that are the NAS heads constituting the scale-out NAS group 111. The enclosure 10 permits insertion into general-purpose slots 104 in which the NAS head members 110L and another type of channel control unit 112 that differs from the NAS head membe...

A system and method for cache management in a data processing system having a memory hierarchy of upper memory and lower memory cache. A lower memory cache controller accesses a coherency state table to determine replacement policies of coherency states for cache lines present in the lower memory cache when receiving a cast-in request from one of the upper memory caches. The coherency state table implements a replacement policy that retains the more valuable cache coherency state information bet...

A system and method is provided to support immediate freeing of a designated element from memory. Following a process of designating an element for removal from a data-structure, conditional limitations are used to determine if immediate freeing of the element from memory is available. The conditional limitations include determining that the instruction originates from a uniprocessor computer system. In addition, the conditional limitations include a determination as to whether a call_rcu primit...

The present invention relates to a method and a device for the fast verification of sector addresses in a data stream obtained from a recording medium upon a request from a microcontroller. According to the invention, the method comprises the steps of: reading the data stream from the recording medium; decoding the data stream to obtain a decoded data stream comprising user data and sector addresses; comparing the sector addresses with a range of valid sector addresses; and transmitting only use...

A data processing system includes a memory controller of a system memory that receives first and second castout operations both specifying a same address. In response to receiving said first and second castout operations, the memory controller performs a single update to the system memory.

Data storage apparatus comprises a tape drive and a tape cartridge, the tape cartridge having a data storage tape on which write-once-read-many (WORM) data is stored. The data storage apparatus is controlled by providing a format command to the tape drive commanding a formatting operation that conditions the tape for erasure or overwriting of the WORM data. A format command key is provided with the format command to be compared with a key recorded in the cartridge. The format command is enabled ...

A cache coherent data processing system includes a plurality of processing units each having at least an associated cache, a system memory, and a memory controller that is coupled to and controls access to the system memory. The system memory includes a plurality of storage locations for storing a memory block of data, where each of the plurality of storage locations is sized to store a sub-block of data. The system memory further includes metadata storage for storing metadata, such as a domain ...