Method and system for coherently caching I/O devices across a network

A caching system comprising:

• a plurality of computers, each having a memory;
• a network interconnecting said plurality of computers;
• a plurality of I/O devices connected to said network;
• and
• cache software resident in each of said computers, wherein the cache software comprises:
• remote message code that communicates with the cache software on any of said computers;
• data structure code that creates a data structure for each of selected ones of said I/O devices, each said data structure including a list of all of said computers that cache data from the I/O device corresponding to said data structure;
• and
• write instruction code that receives a write instruction to one of said plurality of I/O devices,
• wherein the remote message facility communicates with each computer in the list of computers in the data structure corresponding to said one of said I/O devices to invalidate data in the caches of each computer in the list.

A method for coherently caching I/O devices available for shared access on a network comprising:

• creating a cache in the memory of a computer connected to the network;
• creating a data structure for each of a plurality of I/O devices connected to said network for which data may be cached by said computer, each said data structure including a list of all computers on said network that cache data from the I/O device corresponding to said data structure;
• receiving a write instruction to one of said plurality of I/O devices;
• and
• communicating over the network with each computer in the list of computers in the data structure corresponding to said one of said I/O devices to invalidate data associated with the write instruction.

A method for coherently caching I/O devices available for shared access on a network comprising:

• providing each of a plurality of computers on the network with cache software;
• operating the cache software in each of the plurality of computers;
• intercepting a write instruction to a disk I/O device;
• and
• intercepting a write complete instruction from said one of said I/O devices and responsively sending remote messages to the other cache software caching this I/O device to invalidate the data associated with the write instruction.

A caching system comprising:

• a network;
• a plurality of computers interacting as a shared disk access cluster on said network, each computer having a memory;
• a plurality of I/O devices connected to said network;
• a plurality of cache drivers, each resident in one of said computers, to create a cache in the memory of the computer in which the cache driver resides, said cache being configured to cache data from selected ones of said I/O devices,
• wherein each cache driver knows of the existence of all other cache drivers caching the selected I/O device, and
• wherein each cache driver includes:
• remote messaging code that forms a computer communication channel with a cache driver on any of said computers for sending messages relating to caching, wherein said remote messaging code saves a remote connection address for each of the communication channels;
• and
• listening code that listens on said network for a request from a computer to connect to said network.

A caching system comprising:

• a network;
• a first computer connected to said network said first computer having a memory;
• a second computer connected to said network said second computer having a memory;
• one or more I/O devices connected to said network;
• and
• a plurality of cache drivers, each resident in one of said first and second computers to create a cache in the memory of the computer in which the cache driver resides for caching data from selected ones of said one or more I/O devices, each cache driver including remote messaging code that forms a computer communication channel with a cache driver on another computer on said network via which messages relating to caching may be communicated, said remote messaging code further saving a remote connection address for each computer communication channel formed from the computer in which the cache driver resides.

A method for accelerating access to data on a network having two or more computers with shared access to disk I/O devices connected to said network, said method comprising:

• creating caches in RAMs of a plurality of the computers connected to the network, each cache knowing of the existence of all other caches capable of caching a given I/O device;
• receiving a write instruction to the given one of the I/O devices connected to the network;
• sending the write instruction to the given I/O device;
• receiving a write completion instruction from given the I/O device;
• communicating over the network to invalidate data in other remote caches known to be caching the given I/O device.