International Business Machines Corporation

Newisys, Inc.

Carl Zeitler, Jr

Roger L Cormier

Robert J Dugan

Richard R Oehler

Paul J Wanish

Joseph R Mathis

Richard R Guyette

Ming C Hao

Michael Howard Hartung

Brian B Moore

Kenneth R Lynch

Richard Ormond Simpson

Richard G Fogg, Jr

Neal T Christensen

Arthur L Levin

Howard Loomis Page

Joseph A Wetzel

David H Wansor

John L Burk

Ray A Larner

George A McClain

Robert H Werner

Donald J Lucas

Ronald L Hankison

William C Van Loo

According to the present invention, methods and apparatus are provided for static and dynamic power management of computer systems. A power authority manages power usage levels in computer systems by monitoring power consumption levels and providing power consumption information to the various systems. In one example, the power authority updates power tables to vary aggregate power consumption levels.

Methods and apparatus for static and dynamic power management of computer systems

A data processing system including a processor that issues communications commands on a first communications channel and a peripheral device that is connected to the first communications channel and to a second communications channel that operates asynchronously relative to the first communications channel. The peripheral device performs communications operations specified from the commands from the processor and further responds to communications over the second communications channel. The peripheral device includes a controller that provides a status word to the processor in response to the command issued to the peripheral device. The status word indicates the status condition of the peripheral device at the time when the peripheral device initiates the operation specified by the issued command.

Input/output initiate command mechanism

In a communications system, a sending system and a receiving system have multiple data buffers. In response to an inquiry from the sending system, the receiving system transmits information which indicates the size and number of data buffers available in the receiving system. The sending system then begins transmitting data frames, which are placed into the buffers of the receiving system. When the receiving system removes all of the data from a buffer, therefore freeing it to accept additional data, it sends a signal to the sending system indicating this fact. The sending system counts such signals, and ensures that the number of transmitted data frames does not exceed the number of frames which have been removed from the receiver's buffers by more than the number of buffers which the receiver has.

System and method for data communications

A channel for a data processing system is provided with a time of day clock that is synchronized with the time of day clock of the associated central processor. Both the central processor and the channel processor record times of particular events, and the channel uses these times to calculate two times called Function Pending and Function Active. Both times begin when the central processor executes an instruction to begin an I/O operation. Function Pending ends when the channel has made successful initial selection. This time shows delays by the channel processor in scheduling the channel control unit, and device resources for I/O operations. Function Active ends at Channel End. A new instruction, Set Channel Monitor, enables or disables these measurements. An information block for each subchannel defines one of several measurement modes for a subchannel or disables the subchannel from measurement.

Method and apparatus for measurements of channel operation

Multiprocessing systems having changeable CPU configurations generate unique changeable identifications (ID's). These are presented by I/O channels over various I/O connection paths, in association with special path defining commands and function data. Related path state indications are stored peripherally in path map tables and define path group associations for sustaining path-independent I/O operations. When a device is reserved via one path in a path group the reserve affiliation is extended automatically (in the path tables ) to each path in the group, thereby rendering each path accessible in a reserved mode. The path defining commands are used for adding paths to, resigning paths from and disbanding groups. Special sensing commands are used for sensing path reservation and grouping states. When a command for adding or resigning a path is presented to a reserved device via one path in a group the reserve is automatically realigned to the enlarged or reduced group. When a command for disbanding a group is presented to a reserved device the reserve is realigned to apply only to the path on which the command is presented. The foregoing special commands are required to be obeyed by the device even if it currently has a conflicting allegiance to the same system or another system. Consequently, paths can be added to an established path group without requiring potentially premature release of any allegiance.

Method for establishing variable path group associations and

Secondary storage subsystems exchange messages and data with host data processing systems and also forward messages between host systems. Host systems thereby communicate with each other in addition to having access to data in subsystem storage. Access to subsystem storage is initiated by a 'request' sent from a host to the subsystem. Each request is a message containing an array of one or more commands, each command specifying a transfer of data or a control function to be performed by the subsystem. A subsystem may process more than one request at a time. It also may process the commands in a request in an arbitrary sequence suited to the availability of subsystem resources and data links to host systems. After all commands in a request have been processed the subsystem transmits an associated 'completion' message to the host system which originated the request. The completion message indicates the status of completion or abnormal termination of each command in the associated request. An 'adapter' processor associated with each host and subsystem operates on an asynchronous basis to transfer messages and data relative to the associated host or subsystem. One or more processing 'engines' in each adapter communicates with one or more CPU's in the associated host or subsystem through an associated 'adapter store'. A portion of each adapter store is used as a buffer pool for constructing 'subchannel control spaces' to control transers of messages and data. Elements of each subchannel control space are returned to free status as soon as they are not needed for sustaining associated transfers.

Block transfers of information in data processing networks

The disclosure relates to multiprocessor handling of plural queues of pending I/O interrupt requests (I/O IRs) in a main storage (MS) shared by plural central processors (CPs). An input/output processor (IOP) inserts I/O IR entries onto the queues in accordance with the type of interrupt. The entries in the queues are only removed by the CPs, after their selection by a system controller (SC) for execution of an interruption handling program. An I/O interrupt pending register in I/O interrupt controller circuits in the SC is used in selecting CPs to handle the I/O IRs on the queues. The bit positions in the pending register are respectively assigned to the I/O IR queues in MS, and the order of the bit positions determines the priority among the queues for CP handling. An I/O IR command from the IOP to the SC sets a corresponding queue bit position in the pending register and controls the addition of an entry on the corresponding queue in MS. If a bit is set to one, the corresponding queue is non-empty; if set to zero, the queue is empty. A broadcast bus connects the outputs of the bit positions of the pending register to each of the CPs. In each CP, acceptance determining circuits connect to the broadcast bus and accept the highest-priority-unmask non-empty-state bit position being broadcast. From this, the CP sends the SC an accepted queue identifier signal and an accept signal when the CP is in an interruptable state. The CP also sends to the SC a wait state signal if the CP is then in wait state. Selection determining circuits in the SC receive the accept, wait (if any), and queue identifier signals from all accepting CPs and select one accepting CP per accepted queue at any one time. The selection circuits can perform the selection of plural CPs in parallel, and send a select signal to each selected CP. An inhibit register in the interrupt controller in the SC inhibits selected bits on the broadcast bus to all CPs except the selected CP for the selected queue identifier. The inhibit on any bit is removed when the selected CP ends its acceptance of the corresponding queue, so that any CP can select the next entry on the corresponding queue. When any selected CP finds it has emptied a queue, it activates a reset line to the SC which resets the corresponding bit in the pending register to indicate the empty state.

Multiprocessor mechanism for handling channel interrupts

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Poughkeepsie, NY, United States of America

Carl Zeitler, Jr