International Business Machines Corporation

Other

Stephen Edwin Smith

Clement Richard Attanasio

Bowen L Alpern

German Sergio Goldszmidt

James Lyle Peterson

Hung-yang Chang

Christos Alkiviadis Polyzois

Anthony Cocchi

Guerney-Douglass Holloway Hunt

Maria Angela Butrico

Guerney Douglas Hunt

A device for transporting strollers includes a base member having a plurality of compartments, a plurality of wheels for supporting the base member wherein two such wheels are mounted adjacent the rear portion and another wheel is pivotally mounted to the base member. A plurality of elongated straps are secured to the top surface and to a stroller positioned thereon respectively. The device further includes a mechanism for rotating at least two of the plurality of wheels and a hand-operable remote control unit for selectively transmitting RF signals to the rotating mechanism. The rotating mechanism includes a plurality of motors, at least one power source disposed within select ones of the plurality of compartments, a receiver for receiving the RF signals generated from the remote control, and a microprocessor electrically coupled to the receiver.

Device for transporting a stroller

A method and apparatus are disclosed for efficiently creating and maintaining a remembered set in a generational garbage collection scheme using a write buffer and a barrier bit associated with each object. A barrier bit associated with each object differentiates generations in a generational garbage collection scheme. When an object is first created, the barrier bit of the object is set to zero. The barrier bit is set when the object becomes old, for example, after surviving a first garbage collection. The barrier bit is used to determine whether to make an entry into a write buffer when a reference to another object is stored into an object. An entry is made in the write buffer only if the barrier bit of the object that is written into is set. At the end of each garbage collection, entries in the write buffer are added to the remembered set for the next garbage collection if the objects satisfy the criterion for membership, i.e., they are live and may contain pointers to objects in a younger generation. Thus, the remembered set consists of objects that were in the write buffer at the time of a garbage collection, that must be remembered for the next garbage collection. The write buffer is kept small by eliminating duplicate entries. The present invention turns off the barrier bit after the first store during each reclamation period (which causes the object to be identified in the write buffer). The barrier bit is turned on again by the garbage collector after the write buffer has been processed.

Method and apparatus for performing generational garbage collection using barrier bits

A TCP-connection-router performs encapsulated clustering by dividing each encapsulated cluster into several Virtual EC (VECs), dynamically distributing incoming connections within a VEC based on current server load metrics according to a configurable policy. In one embodiment, the connection router supports dynamic configuration of the cluster, and enables transparent recovery which provides uninterrupted service to the VEC clients.

System and method for providing dynamically alterable computer clusters for message routing

A method and apparatus are provided for the efficient management of remembered sets in a generational garbage collection scheme. The present invention detects when an old object has a pointer to a young object, and needs to be added to the remembered set. A write buffer and a temporary buffer are used to create and maintain the remembered set. Entries in the write and temporary buffers are used as part of the root set for creating the remembered set for the next garbage collection. A barrier bit associated with each object differentiates generations in the generational garbage collection scheme and is used to determine whether to make an entry into a write buffer when a reference to another object is stored into an object. Objects that have survived one or more collections, but not the minimum number, N, of collections to be considered an old object are referred to as &ldquo;middle-aged&rdquo; objects. During a minor garbage collection, the write buffer is scanned. Objects identified in the write buffer are transferred to the remembered set for the next cycle if the object is (i) an old object pointing to a younger object, or (ii) a middle-aged object that is determined to be live. Middle-aged objects identified in the write buffer that are not yet known to be live are transferred to the temporary buffer. At the end of the minor collection, the temporary buffer is processed and objects that are then known to be live are transferred into the remembered set.

Method and apparatus for performing generational garbage collection using middle-aged objects

A method and apparatus are provided for the efficient management of remembered sets in a generational garbage collection scheme. In order to manage the remembered set, the present invention provides a first mechanism for detecting when an old object has a pointer to a young object, and needs to be added to the remembered set, and a second mechanism for detecting when an object already in the remembered set no longer contains a pointer to a young object, so that the object can be removed from the remembered set. Entries in the remembered set have an associated counter, C, identifying the garbage collection cycle during which the object was placed in the remembered set. Objects inserted into the remembered set are assumed to point to the youngest possible object. Entries automatically expire from the remembered set when the garbage collection counter reaches C&plus;N, since the objects pointed to by the object in the remembered set must now themselves be old objects. If an old object (one that has survived at least N garbage collections) is identified during a minor garbage collection, the old object is scanned normally, and is placed into the remembered set, with a counter C identifying the garbage collection cycle during which the old object was placed in the remembered set. The counter identifies the age of the youngest possible object pointed to by this object. When the garbage collection count reaches C&plus;N, this entry can be discarded from the remembered set, since the associated object cannot point to any objects that are not old unless another more recent entry in the remembered set or write buffer exists for that object.

Method and apparatus for performing generational garbage collection using remembered set counter

The invention provides a method for compacting transactions which have committed at a disconnected client prior to sending the transactions to the server for replaying along with an iterative process for re-calculating the combined transaction in the event that replay at the server fails.

Transaction compaction for replay of transactions from client to server

System and method for providing dynamically alterable computer clusters

A system and method for recovering from failures in the disk access path of a clustered computing system. Each node of the clustered computing system is provided with proxy software for handling physical disk access requests from applications executing on the node and for directing the disk access requests to an appropriate server to which the disk is physically attached. The proxy software on each node maintains state information for all pending requests originating from that node. In response to detection of a failure along the disk access path, the proxy software on all of the nodes directs all further requests for disk access to a secondary node physically attached to the same disk.

Virtual shared disks with application transparent recovery

The present invention provides a method and apparatus for enabling a cluster of computers to appear as a single computer to host computers outside the cluster. A host computer communicates only with a gateway to access destination nodes and processes within the cluster. The gateway has at least one message switch which processes incoming and outgoing port type messages crossing the cluster boundary. This processing comprises examining certain information on the message headers and then changing some of this header information either to route an incoming message to the proper computer node, port and process or to make an outgoing message appear as if originated at the gateway node. The message switch uses a table to match incoming messages to a particular routing function which can be run to perform the changes necessary to correctly route different kinds of messages.

Growing community of inventors

Mahopac, NY, United States of America

Stephen Edwin Smith