Abstract: A fault-tolerant RAID system is disclosed. The system includes redundant RAID controllers coupled by a PCI-Express link. When a PCI-Express controller of one of the RAID controllers receives a PCI-Express memory write request transaction layer packet (TLP), it interprets a predetermined bit in the header as an interrupt request flag, rather than as its standard function specified by the PCI-Express specification. If the flag is set, the PCI-Express controller interrupts the processor after storing the message in the payload at the specified memory location. In one embodiment, an unused upper address bit in the header is used as the interrupt request flag. Additionally, unused predetermined bits in the TLP header are used as a message tag to indicate one of a plurality of message buffers on the receiving RAID controller into which the message has been written. The PCI-Express controller sets a corresponding bit in a register to indicate which message buffer was written.

Abstract: A method for improving performance through selective file caching is disclosed. The caching policy of a client's browser cache is set to cache all files. Web page files that reference a dynamic file include JavaScript code that mangles the dynamic filename, such that a reference by the web page file to the dynamic file is unique each time a browser, processes the web page file. In one embodiment, the filename is mangled by appending to it a known string followed by a 12-digit timestamp. Consequently, the mangled filename misses in the cache, forcing the browser to fetch the dynamic file from the web server. The web server recognizes the filename is in the mangled format, regenerates the original filename, and returns the file to the client. Static filenames are not mangled; hence, they are satisfied from the browser cache. The method also works to selectively defeat network caching.

Abstract: A system for performing an efficient mirrored posted-write operation having first and second RAID controllers in communication via a PCI-Express link is disclosed. The first bus bridge transmits a PCI-Express memory write request TLP to the second bus bridge. The TLP header includes an indication of whether the first CPU requests a certification that certifies the payload data has been written to the second write cache memory. If the indication requests the certification, the second bus bridge automatically transmits the certification to the first bus bridge independent of the second CPU, after writing the payload data to the second write cache memory. The first bus bridge generates an interrupt to the first CPU in response to receiving the certification. The certified transfer may be used to validate and/or invalidate mirrored copies of a write cache directory on the RAID controllers, among other uses.

Abstract: A write-caching RAID controller is disclosed. The controller includes a CPU that manages transfers of posted-write data from host computers to a volatile memory and transfers of the posted-write data from the volatile memory to storage devices when a main power source is supplying power to the RAID controller. A memory controller flushes the posted-write data from the volatile memory to the non-volatile memory when main power fails, during which time capacitors provide power to the memory controller, volatile memory, and non-volatile memory, but not to the CPU, in order to reduce the energy storage requirements of the capacitors. During main power provision, the CPU programs the memory controller with information needed to perform the flush operation, such as the location and size of the posted-write data in the volatile memory and various flush operation characteristics.

Abstract: A method for improving performance through selective file caching is disclosed. The caching policy of a client's browser cache is set to cache all files. Web page files that reference a dynamic file include JavaScript code that mangles the dynamic filename, such that a reference by the web page file to the dynamic file is unique each time a browser, processes the web page file. In one embodiment, the filename is mangled by appending to it a known string followed by a 12-digit timestamp. Consequently, the mangled filename misses in the cache, forcing the browser to fetch the dynamic file from the web server. The web server recognizes the filename is in the mangled format, regenerates the original filename, and returns the file to the client. Static filenames are not mangled; hence, they are satisfied from the browser cache. The method also works to selectively defeat network caching.