Abstract: A storage area network (SAN) fibre channel arbitrated loop (FCAL) multiple system, multiple resource, storage enclosure and a method are provided for performing enclosure maintenance concurrent with device operations. The storage enclosure includes a plurality of storage resources or storage devices, a plurality of IO adapters (IOAs) coupled to the storage area network and a pair of enclosure services node cards. Each enclosure services node card includes loop connections for the plurality of storage resources. Each enclosure services node card includes a respective global bus connection and a loop connection to each of the plurality of IOAs. Each enclosure services node card is used concurrently by the multiple systems to manage the plurality of storage resources. In the method for performing enclosure maintenance concurrent with device operations, identical maintenance procedures are implemented for the enclosure services node cards and the storage devices.

Abstract: A method, system and program for controlling access to memory areas within a computer are provided. The invention comprises placing a first Bind Work Queue Element (WQE) at the head of a work queue, wherein the first Bind WQE defines parameters associated with a first Memory Window. A set of Work Requests is then placed on the work queue, behind the first Bind WQE wherein the work requests invoke operations that access the first Memory Window. A second Bind WQE is then placed on the work queue, behind the first set of Work Requests. This second Bind WQE defines parameters associated with a second Memory Window. A second set of Work Requests is placed on the work queue behind the second Bind WQE and invoke operations that access the second memory window. The Memory Windows can be associated with a common Memory Region and have different addresses and lengths or different access rights. In another embodiment, the first and second Memory Windows can be associated with different Memory Regions.

Abstract: A method, system and program for controlling access to computer memory are provided. The present invention comprises receiving a work request from a user, wherein the work request comprises an index portion and a protection portion. The index portion of the work request is used to locate an element in an address translation and protection table. The protection portion of the work request is then compared with a protection key in the table element, and access to memory is granted only if the protection portion and protection key match.

Abstract: A storage area network (SAN) fibre channel arbitrated loop (FCAL) multiple system, multiple resource, storage enclosure and a method are provided for performing enclosure maintenance concurrent with device operations. The storage enclosure includes a plurality of storage resources or storage devices, a plurality of IO adapters (IOAs) coupled to the storage area network and a pair of enclosure services node cards. Each enclosure services node card includes loop connections for the plurality of storage resources. Each enclosure services node card includes a respective global bus connection and a loop connection to each of the plurality of IOAs. Each enclosure services node card is used concurrently by the multiple systems to manage the plurality of storage resources. In the method for performing enclosure maintenance concurrent with device operations, identical maintenance procedures are implemented for the enclosure services node cards and the storage devices.

Abstract: A method, system and program for controlling access to computer memory are provided. The present invention comprises receiving a work request from a user, wherein the work request comprises an index portion and a protection portion. The index portion of the work request is used to locate an element in an address translation and protection table. The protection portion of the work request is then compared with a protection key in the table element, and access to memory is granted only if the protection portion and protection key match.

Abstract: A method, system and program for controlling access to memory areas within a computer are provided. The invention comprises placing a first Bind Work Queue Element (WQE) at the head of a work queue, wherein the first Bind WQE defines parameters associated with a first Memory Window. A set of Work Requests is then placed on the work queue, behind the first Bind WQE wherein the work requests invoke operations that access the first Memory Window. A second Bind WQE is then placed on the work queue, behind the first set of Work Requests. This second Bind WQE defines parameters associated with a second Memory Window. A second set of Work Requests is placed on the work queue behind the second Bind WQE and invoke operations that access the second memory window. The Memory Windows can be associated with a common Memory Region and have different addresses and lengths or different access rights. In another embodiment, the first and second Memory Windows can be associated with different Memory Regions.

Abstract: A method, system, and apparatus for processing foreign protocol requests, such as PCI transactions, across a system area network (SAN) utilizing a data packet protocol is provided while maintaining the other SAN traffic. In one embodiment, a HCA receives a request for a load or store operation from a processor to an I/O adapter using a protocol which is foreign to the system area network, such as a PCI bus protocol. The HCA encapsulates the request into a data packet and places appropriate headers and trailers in the data packet to ensure that the data packet is delivered across the SAN fabric to an appropriate TCA to which the requested I/O adapter is connected. The TCA receives the data packet, determines that it contains a foreign protocol request, and decodes the data packet to obtain the foreign protocol request. The foreign protocol request is then transmitted to the appropriate I/O adapter.

Abstract: Method and apparatus for managing data on DASD units to improve system performance comprises monitoring portions of data on a plurality of DASD units to determine the times the data is accessed within a given time period, and characterizing accessed data portions of a DASD unit as HOT and COLD data. The DASD units are monitored to determine the number of times each unit is accessed within a time period to develop utilization factors reflective of the number of times the DASD unit is accessed during the time period. HOT and COLD data is moved between DASD units based on the utilization factors of the DASD units.

Abstract: System control of compression and decompression of data based upon system aging parameters, such that compressed data becomes a system managed resource with a distinct place in the system storage hierarchy. Processor registers are backed by cache, which is backed by main storage, which is backed by decompressed disk storage, which is backed by compressed disk storage then tape, and so forth. Data is moved from decompressed to compressed form and migrated through the storage hierarchy under system control according to a data life cycle based on system aging parameters or, optionally, on demand: data is initially created and stored; the data is compressed at a later time under system control; when the data is accessed, it is decompressed on demand by segment; at some later time, the data is again compressed under system control until next reference. Large data objects are segmented and compression is applied to more infrequently used data.

Abstract: System control of compression and decompression of data based upon system aging parameters, such that compressed data becomes a system managed resource with a distinct place in the system storage hierarchy. Processor registers are backed by cache, which is backed by main storage, which is backed by decompressed disk storage, which is backed by compressed disk storage then tape, and so forth. Data is moved from decompressed to compressed form and migrated through the storage hierarchy under system control according to a data life cycle based on system aging parameters or, optionally, on demand: data is initially created and stored; the data is compressed at a later time under system control; when the data is accessed, it is decompressed on demand by segment; at some later time, the data is again compressed under system control until next reference. Large data objects are segmented and compression is applied to more infrequently used data.

Abstract: A method and apparatus are provided for adaptive localization of frequently accessed, randomly addressed data in a direct access storage device (DASD) to achieve improved system access performance. At selected sampling intervals, a DASD storage controller analyzes data access patterns based on frequency of access, identifies a remapping algorithm to remap the logical groups to physical groups, and moves the physical groups according to the identified remapping algorithm. The data reordering on the DASD provides frequently accessed data in close proximity so that seek time is minimized. The adaptive data localization method periodically performed by the storage controller is transparent to the host file system. The reordering of the data on the DASD is performed during periods of low system data transfer activity.

Abstract: An embedded directory record and method are provided for maintaining directory information for compressed data on a direct access storage device (DASD). The embedded directory record includes a plurality of page entries, a plurality of exception region entries and a plurality of compression group statistics. Each page entry includes an allocated page length value and a number of used sectors value in the allocated page. The exception region entries include a page index and a bit map used for identifying exception sectors used. The compression group statistics include a total count of allocated sectors, a total count of the used sectors; and a total count of written pages. A starting page address for a requested page is identified beginning at a start of the page entries by summing the allocated page length values for each page up to the requested page to identify an offset value and combining the offset value with a predetermined logical block address.

Abstract: A method and apparatus for maintaining and rebuilding directory information for compressed data on a direct access storage device are provided. A directory of DASD compressed data is stored in the storage controller and directory information is periodically written to the DASD for compressed data written to the DASD. A drive write count (DWC) of each write operation to the DASD is maintained. A number of sectors in a compressed data page is identified for the drive write count. A sector sequence number is identified for each of the number of sectors in the compressed data page. A span for the compressed data page is identified for the drive write count. A page offset is identified for the identified number of sectors in the compressed data page. A deallocation status of a first page of an extent is identified. The extent is a block of sequential compressed data pages.

Abstract: A data compression storage method and data compression hierarchical padding structure are provided for a direct access storage device (DASD) using fixed block architecture (FBA). A minimum page allocation defining a minimum number of sectors allocated for each logical compressed data page is selected. The DASD is segmented into at least one compression group. Each compression group has a fixed logical size and includes a selected number of DASD compressed data pages with an initial page allocation of a number of sectors. The initial page allocation is greater than or equal to the minimum page allocation. A minimum number of compressed data regions is allocated within each compression group. A selected number of additional compressed data regions including a plurality of sectors for padding is allocated within each compression group. The plurality of padding sectors are distributed between the compression pages. An exception region is allocated within each compression group.