International Business Machines Corporation

Mcdata Corporation

Kenneth J Fredericks

Leslie W Wyman

Kenneth J Oakes

Roger E Hough

Marten J Halma

Suzanne M John

Thomas Anthony Gregg

Robert Edward Galbraith

Allan Samuel Meritt

Joseph C Elliott

Michael E O'Donnell

James C Mazurowski

Michael R Wiegand

Roger Gregory Hathorn

Moon Jung Kim

Giles R Frazier

Charles Franklin Webb

Robert J Dugan

Douglas W Westcott

Eugene P Hefferon

Joseph J Kubik

Martin W Sachs

Charles E Shapley

Patrick John Sugrue

Gregory Salyer

Peter H Gum

Paul J Brown

Anthony R Sager

Lee Hardy Wilson

Allen H Preston

Gerald H Miracle

David E Stucki

Richard Roland Guyette

Kenneth R Lynch

Richard Cwiakala

Frank W Brice

Roger L Cormier

Assaf Marron

John C Rathjen, Jr

Clifford T Williams

Gerald T Moffitt

Richard J Schmalz, Deceased

Paul A Malinowski

David W Hollar

Kenneth A Meifert, Jr

John F Santiamo

Miriam P Brown

Paul W Jones

Thomas W Guerriero

A method for implementing a link level service in a computer network having a first port device and a second port device. Node identification data is stored in the second port device. A physical-layer communications coupling is provided between the first port device and the second port device which may be a point-to-point, loop, or switched circuit connection. The first port device sends a request node identification (RNID) message addressed to the second port device. The second port device creates an accept message and copies stored node identification data into the accept message. The second port device sends the accept message to the first port device.

Self-description extended link service for networks

A method for implementing a link level service in a computer network having a first port device and a second port device coupled by a communication link. Prior to a link incident being reported, the first port device executes a link incident record registration (LIRR) ELS message addressed to the second port device. The second port device responds to the LIRR by adding an address of the first port device to a registration list of ports registered to receive link incident reports. The second port device also responds to the LIRR by sending an accept reply message addressed to the first port device. After a link incident is detected by the second port device, the second port device generates a link incident record comprising data describing the link incident. The second port device selects an address from the registration list sends a registered link incident record ELS message addressed to the selected address.

Link incident reporting extended link service for networks

Enables any OS of plural OSs within any of plural logical-resource partitions (LPARs) of a CEC to use interpretive execution for synchronously-executable CHSC (channel subsystem call) commands. A CHSC command authorization mask (CCAM) is provided to control which CHSC commands are allowed to execute interpretively (with pass-through), and which commands are executed with hypervisor intervention (as all prior CHSC commands did). By enabling interpretive execution of those commands which can successfully operate with pass-through, significant system efficiency is obtained. And by disabling interpretive execution for a subset of CHSC commands (which are not allowed to execute with pass-through) potential system failures may be prevented. Thus, interpretive execution may be restricted differently among the OSs in a CEC. Novel CHSC command execution now handles multiple images of shared I/O resources by use of image identifiers, which could not be done before. The information requested by any OS issuing a CHSC command is filtered and optionally compacted by the I/O subsystem responding to the command by only providing information obtained from control blocks associated with the OS which issued the command. This is done by having a set of control blocks for each I/O resource, each control block in the set being associated with a particular OS.

Pass-through for I/O channel subsystem call instructions for accessing

Enables an I/O channel program to use IDAWs (indirect data address words) to control data transfers from/to an I/O (input/output) device to/from either or both of ES (expanded storage) and/or system MS (main storage), in which data moved to/from ES does not move through MS. ES and MS are plural electronic storage media in a data processing system, and the I/O device is any I/O device selectable by the system. Intermixing of data transfers between ES and MS may be controlled by a single IDAW list accessed by a channel control word (CCW) in a channel program in a data transfer direction indicated in the CCW without any channel mode change.

System for transferring data between I/O devices and main or expanded

This invention involves reconfiguration support for shared I/O resources in a a computer electronic complex (CEC) supporting both shared and unshared I/O channels of the type described and claimed in U.S. patent application Ser. No. 07/898,867 (PO9-92-016) filed on the same day as the subject application and assigned to the same assignee as the subject application. Prior channel subsystem call (CHSC) instructions cannot execute when a channel is to be configured as shareable by plural operating systems in a CEC.

Asynchronous command support for shared channels for a computer complex

A system for the transmission of information between elements of a data processing complex and a method for establishing such a system. Two elements of a data processing system are connected by a physical link comprising multiple conductors attached to transceivers at channels in each data processing element. Once the transceivers have been synchronized, commands and responses are exchanged which ensure that all of the transceivers in a channel are connected to the same channel on the other end of the conductor. If the transceivers are considered configured an entry is made in a Configured-Transceiver table. A search is made of an Allowed-Operational-Link table which contains sets of transceivers which are allowed to become operational links. The set of transceivers thus found, is compared against the Configured-Transceiver-Table to verify that all of the members of the set have been configured. If a match is found, this set of transceivers becomes an Intended-Operational-Link. The Intended-Operational-Link is verified to ensure that both channels agree on the set of conductors will form the operational link. If the Intended-Operation-Link verifies, the operational link is established therefrom.

Concurrent maintenance of degraded parallel/serial buses

Provides a method for increasing the connectivity of I/O resources to a multiplicity of operating systems (OSs) running in different resource partitions of a computer electronic complex (CEC) to obtain sharing of the I/O resources among the OSs of the CEC, including channels, subchannels (devices), and control units (CUs). The invention provides image identifiers (IIDs) for assigning resources to the different OSs. Each shared I/O resource has a sharing set of control blocks (CBs) in which a respective CB is assigned to (and located by) a respective IID of one of the OSs. Each of the CBs in a sharing set provides a different image of the same I/O resource. The different CB images are independently set to different states by I/O operations for the different OSs, so that the OSs can independently share the same I/O resource.

Method and means for sharing I/O resources by a plurality of operating

A method for acquiring the node identifier of a node in a data processing input/output (I/O) system having a plurality of nodes. This procedure is part of the initialization of each node in the I/O system and may be used to establish the configuration of the I/O system such that if a connection breaks or a fault occurs between nodes, the configuration can be confirmed after the break or fault is corrected. This prevents data from being sent to the wrong device if lines were connected in a different configuration during the correction of a fault. The node identifier is a worldwide-unique identifier such that only one node is identified by a node identifier. The node identifier contains a validity code that specifies if the node identifier is valid. Also disclosed is a retry procedure for retrying the acquisition of a node identifier if the acquired node identifier is not valid, and a deferral procedure which defers the retry procedure if a link is not available.

Method for requesting identification of a neighbor node in a data

Methods and apparatus are described, in the context of an information handling system, that permit data chaining in a data streaming mode to be performed through a channel extender. The information handling system includes a processor channel and a peripheral device controller which communicate with one another over the channel extender. The invention allows the separation between the processor channel and peripheral device controller to be extended up to several (e.g. 1, 2 or 3) kilometers versus the less than 0.5 kilometer separation imposed by state of the art systems. Furthermore, the invention allows the objective of increased channel extender length to be accomplished without the risk of data overruns, chaining checks or peripheral device controller signalled errors which would otherwise occur as a result of requests for data or data transfers being in flight on an extended link.

Methods and apparatus for performing data chaining in data streaming

A link-level facility for managing the transmission of frames and continuous sequences of control characters over a link. The link-level facility includes a state machine which has a first state for allowing transmission of a frame over the link where a link-level facility at the other end of the link indicates that the link has a frame-transmitting status, and a second state for preventing the transmission of frames over the link when the link-level facility at the other end of the link has indicated that the link has a non-frame-transmitting status. The link-level facilitates signal the status of the link by means of continuous sequences of special characters intermediate frames transmitted over the link such that synchronism is maintained. The first state includes an inactive state and a working state, and the second state includes a link-failure state, and connection-recovery state and an off-line state.

Managing a serial link in an input/output system which indicates link

An information handling system includes a processor with one or more channels for communicating to peripheral devices controlled by peripheral device controllers, and one or more serial data links between the channels and the peripheral controllers. Data is transmitted over the serial data link between the channels and the controllers in a frame format, wherein each frame includes a number of eight-bit characters selected so that all standard parallel interface tag and data lines are transmitted in a single frame with a high degree of error immunity resulting from selection of idle characters and frame start characters having the mutual characteristic that single and double bit errors in the idle characters do not create an erroneous indication of a start character in the system.

Information handling system having serial channel to control unit link

Data is transferred between a channel and a control unit in interlocked mode or in data streaming mode over a conventional parallel bus and a serial link that permits the control unit and the channel to be located farther apart than the length of the parallel bus. The serial link carries frames for the rise of the data transfer tags but not their fall, and these tags on the parallel bus are dropped by two circuits that connect the serial link to the parallel bus. In data streaming mode, one data transfer tag is dropped when the next data transfer tag is received on the serial link. The circuit at the control unit end of the serial link detects a pause in the tags to begin an operation to drop the last data transfer tags and both circuits respond to other conditions to drop the last data transfer tags according to the protocol of the parallel bus.

Serial channel interface with method and apparatus for handling data

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Poughkeepsie, NY, United States of America

Kenneth J Fredericks