Abstract: A method and apparatus are provided for dynamically determining a primary adapter in a heterogeneous N-way adapter configuration. Each of the adapters generates information about itself and exchanges the information with all other adapters. First a decision-making adapter is identified. Then the decision-making adapter compares the adapter-generated information of all the adapters and makes a decision determining the primary adapter. The decision-making adapter communicates the decision to all other adapters. The determined primary adapter assumes a role as the primary adapter and the other adapters assume a role as a secondary adapter.

Abstract: A method and apparatus are provided for dynamically determining a primary adapter in a heterogeneous N-way adapter configuration. Each of the adapters generates information about itself and exchanges the information with all other adapters. First a decision-making adapter is identified. Then the decision-making adapter compares the adapter-generated information of all the adapters and makes a decision determining the primary adapter. The decision-making adapter communicates the decision to all other adapters. The determined primary adapter assumes a role as the primary adapter and the other adapters assume a role as a secondary adapter.

Abstract: A method and apparatus are provided for implementing distributed (SCSI) devices using enhanced adapter reservations. A plurality of adapters is provided. Each adapter implements a plurality of logical devices with each logical device respectively coupled to a port of the distributed SCSI devices. The adapters manage reservations for the plurality of logical devices selectively using a no reservation state, an implicit reservation state, and an explicit reservation state. The adapters arbitrarily assign one adapter for managing each of the plurality of logical devices.

Abstract: In a first aspect, a method is provided for updating a compressed cache. The method includes the steps of (1) initiating an update routine for replacing first data stored within the cache with second data, wherein a first section of a compressed data band stored in the cache includes the first data and a second section of the compressed data band includes third data; and (2) in response to initiating the update routine, replacing the first data within the compressed data band with the second data without decompressing the third data. Numerous other aspects are provided.

Abstract: In a first aspect and in a computer system that runs more than one operating system, a scheme for mapping memory locations in a data storage device is provided. A range of logical memory addresses at a low end of a logical memory address space is duplicated, and each duplicate range is assigned to a respective operating system, and mapped to a respective range of the storage device's physical memory address space, thereby reserving respective portions of the physical memory address space for writing of each operating system's configuration data.

Abstract: In a first aspect and in a computer system that runs more than one operating system, a procedure for controlling access to a data storage device is provided. The data storage device stores a token which identifies the operating system to which the data storage device is assigned. An operating system seeking to access the data storage device is identified by a token, and if that token does not match the token stored in the data storage device, access to the data storage device is prevented.

Abstract: In a first aspect, a method is provided for updating a compressed cache. The method includes the steps of (1) initiating an update routine for replacing first data stored within the cache with second data, wherein a first section of a compressed data band stored in the cache includes the first data and a second section of the compressed data band includes third data; and (2) in response to initiating the update routine, replacing the first data within the compressed data band with the second data without decompressing the third data. Numerous other aspects are provided.