A disk storage subsystem includes both volatile and non-volatile portions of memory. In response to a write command from a host computer, the controller allocates a predetermined number of memory blocks in the non-volatile cache memory and allocates a corresponding number of blocks in the volatile memory. Host supplied write data is then stored in the allocated non-volatile memory blocks. The data may also be mirrored in additional non-volatile memory. Immediately thereafter the subsystem sends an acknowledge signal to the host. The subsystem then performs a DMA operation to copy the write-data from the non-volatile memory blocks to the volatile memory blocks. The write-data is then stored on a disk drive at which point the non-volatile memory may be de-allocated. Subsequent reads of the given data may be read from the volatile memory, reducing disk access time. In the event of a power failure, data stored in the non-volatile memory but not yet written to disk is preserved. In the event of a disk controller failure, the non-volatile memory modules may be transferred to a functioning disk controller for recovery.

Disk controller with volatile and non-volatile cache memories

A method for securing remote access to private networks includes a receiver intercepting from a data link layer a packet in a first plurality of packets destined for a first system on a private network. A filter intercepts from the data link layer a packet in a second plurality of packets transmitted from a second system on the private network, destined for an system on a second network. A transmitter in communication with the receiver and the filter performing a network address translation on at least one intercepted packet and transmitting the at least one intercepted packet to a destination.

A method and systems for securing remote access to private networks

A method for routing packets from a gateway to an endpoint includes the step of associating a private internet protocol (IP) address with an endpoint having a public IP address. A packet addressed to the private IP address of the endpoint is captured. A policy is applied to the packet. The packet is transmitted to the public IP address of the endpoint, responsive to the application of the policy to the packet.

Method and systems for routing packets from a gateway to an endpoint

A system and method for establishing a virtual private network (VPN) between a client and a private data communication network. An encrypted data communication session, such as a Secure Sockets Layer (SSL) data communication session, is established between a gateway and the client over a public data communication network. The gateway then sends a programming component to the client for automatic installation and execution thereon. The programming component operates to intercept communications from client applications destined for resources on the private data communication network and to send the intercepted communications to the gateway via the encrypted data communication session instead of to the resources on the private data communication network.

System and method for establishing a virtual private network

The present invention is directed towards a method and system for providing a technique referred to as flash caching to respond to requests for an object, such as a dynamically generated object, from multiple clients. This technique of the present invention uses a dynamically generated object stored in a buffer for transmission to a client, for example in response to a request from the client, to also respond to additional requests for the dynamically generated object from other clients while the object is stored in the buffer. Using this technique, the present invention is able to increase cache hit rates for extremely fast changing dynamically generated objects that may not otherwise be cacheable.

System and method for performing flash crowd caching of dynamically generated objects in a data communication network

A method and apparatus for marking data that is temporarily cacheable to facilitate the efficient management of said data. A bit in the segment and/or page descriptor of the data called the marked data bit (MDB) is generated by the compiler and included in a request for data from memory by the processor in the form of a memory address and will be stored in the cache directory at a location related to the particular line of data involved. The bit is passed to the cache together with the associated real address after address translation (in the case of a real cache). when the cache controls load the address of the data in the directory it is also stored the marked data bit (MDB) in the directory with the address. When the cacheability of the temporarily cacheable data changes from cacheable to non-cacheable, a single instruction is issued to cause the cache to invalidate all marked data. When an "invalidate marked data" instruction is received, the cache controls sweep through the entire cache directory and invalidate any cache line which has the "marked data bit" set in a single pass. An extension of the invention involves using a multi-bit field rather than a single bit to provide a more versatile control of the temporary cacheability of data.

John H. Anthony

Papers

Method and apparatus for efficiently handling temporarily cacheable data