Patents by Inventor Robert W. Shomler

Robert W. Shomler has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5634028
    Abstract: A computer-implemented method for translating from one DASD address to another DASD address initially stores a plurality of translation tables, one translation table for each first DASD coupled to a first processor. Each translation table includes at least a first data value for each cylinder in a first DASD which indicates whether or not the cylinder contains a start-of-extent address. If yes, the translation table has a corresponding translation entry which includes a first portion and a second portion. The first portion includes at least the start-of-extent address in the cylinder and a length of the extent of addresses associated with the start-of-extent address. The second portion includes a start-of-extent address for an address span in a second DASD that corresponds to the first portion.
    Type: Grant
    Filed: December 15, 1994
    Date of Patent: May 27, 1997
    Assignee: International Business Machines Corporation
    Inventors: James T. Brady, Robert W. Shomler, May N. Wone
  • Patent number: 5623599
    Abstract: The present invention relates to event synchronization in asynchronous remote data duplexing, the synchronization being non-disruptive to application execution at a host device and to data copying at a remote site. The event sequence is characterized by embedding labeled tokens of write operations including addresses and periodic checkpoint lists there establishing a total ordering. Event synchronization is achieved by embedding at the host a synchronization request having a higher sequence number than that of some prior predetermined event and generating a responsive synchronization reply from the remote site to the host. The present invention finds use in the communication and remote duplex recording of financial events such as the rare event transfer of large monetary sums in a population of transfers of small sums.
    Type: Grant
    Filed: July 29, 1994
    Date of Patent: April 22, 1997
    Assignee: International Business Machines Corporation
    Inventor: Robert W. Shomler
  • Patent number: 5615329
    Abstract: A remote data shadowing system provides synchronous, storage based, real time disaster recovery wherein a secondary site is located remote from the primary site. An error recovery program at the primary site quiesces applications running thereat for performing error recovery procedures and signalling both primary and secondary locations that failed duplex has occurred. The error recovery program determines the cause of failed duplex, and if error recovery is successful, duplex mode is resumed. If the error recovery program is unable to perform error recovery successfully, then further write updates at the primary site are prohibited and an error message is communicated to operators at both the primary and secondary sites.
    Type: Grant
    Filed: February 22, 1994
    Date of Patent: March 25, 1997
    Assignee: International Business Machines Corporation
    Inventors: Robert F. Kern, William F. Micka, Claus W. Mikkelsen, Michael A. Paulsen, Robert W. Shomler
  • Patent number: 5592618
    Abstract: A data copy validation technique compares primary data to a copy of that data by generating check codes of the data to be validated at both primary and secondary sites in a continuously running remote data shadowing system. The validation session runs concurrently with the data shadowing so as not to disrupt the data shadowing. Each data validation session is assigned a copy start time, for example, a time preceding a time of a consistency group, for defining when the check code for data at the primary should be compared to a check code of the data at the secondary. The check code of the data at the secondary site is taken at a time that is the equivalent logical point-in-time of that data at the primary site even though the respective data contents may be different in real time.
    Type: Grant
    Filed: October 3, 1994
    Date of Patent: January 7, 1997
    Assignee: International Business Machines Corporation
    Inventors: William F. Micka, Claus W. Mikkelsen, Robert W. Shomler, May N. Wone
  • Patent number: 5577222
    Abstract: A system for asynchronously duplexing direct access storage device (DASD) data in a plurality of DASD subsystems has the advantage of decoupling the data duplexing operation from the DASD write I/O operation. This ensures the write does not incur unnecessary wait states in the subsystem. By establishing a sequence checkpoint at which time a set of information packets are grouped together and processed as a single sequence unit, this decoupling and independent operation takes place. Through this independence, data copying to a secondary location can take place without affecting the performance of the subsystems and also not affecting the corresponding integrity of the data that is being updated.
    Type: Grant
    Filed: December 17, 1992
    Date of Patent: November 19, 1996
    Assignee: International Business Machines Corporation
    Inventors: William F. Micka, Claus W. Mikkelsen, Robert W. Shomler
  • Patent number: 5528755
    Abstract: Often in DASD subsystems, circumstances can occur which prevent the full transfer of the required data from channel to subsystem during a write operation. The disclosed methods prevents this data from later being read and treated as valid data by the host processor. This is achieved by marking data as invalid within the storage subsystem once it is determined that a channel error has occured. Subsequently, upon reading that data, the host processor can be made aware of the data invalidity and treat the data accordingly. In a second embodiment, invalid data is discarded rather than stored over the previous valid version of the data, before it is ever stored on DASD.
    Type: Grant
    Filed: December 22, 1992
    Date of Patent: June 18, 1996
    Assignee: International Business Machines Corporation
    Inventors: Brent C. Beardsley, Michael T. Benhase, Susan K. Candelaria, Joel H. Cord, Michael H. Hartung, Bruce M. Henry, Paul Hodges, Paul L. Leung, Robert W. Shomler
  • Patent number: 5446871
    Abstract: A method and system for asynchronous remote data duplexing at a distant location from copies based at a primary site storage subsystem, which copying is non-disruptive to executing applications, and further in which any data loss occasioned by losses in flight or updates never received at the time of any interruption between the primary and remote sites are accounted for at the remote site. The method assigns a token and unique sequence number responsive to each write operation at the primary site, and sends the tokens+numbers and data updates to the remote site. The method relies upon the sequence number to establish a sequency and define gaps therein to ascertain missing updates.
    Type: Grant
    Filed: March 23, 1993
    Date of Patent: August 29, 1995
    Assignee: International Business Machines Corporation
    Inventors: Robert W. Shomler, James E. McIlvain
  • Patent number: 5379385
    Abstract: A method and means for CPU accessing a staged storage subsystem in which rules defining computation of the storage system addresses are distributed with the data, the rules and storage access being interpreted by the sub-system. The method uses local storage address computation in the DASD array context rather than CPU address list generation as has occurred in the prior art.
    Type: Grant
    Filed: November 18, 1992
    Date of Patent: January 3, 1995
    Assignee: International Business Machines Corporation
    Inventor: Robert W. Shomler
  • Patent number: 5283884
    Abstract: A method for managing cache accessing of CKD formatted records that uses a Predictive Track Table to reduce host delays resulting from cache write misses. Because a significant portion of CKD formatted DASD tracks contain records having no key fields, identical logical and physical cylinder and head (CCHH) fields and similar-sized data fields, a compact description of such records by record count and length data, indexed by track, can be quickly searched to determine the physical track location of a record update that misses the cache. The Predictive Track Table search is much faster than the host wait state imposed by access and search of the DASD to read the missing track into cache. If the updated record that misses cache is found within the set of records in the Predictive Track Table, then the update may be immediately written to cache and to a Non-Volatile Store (NVS) without a DASD read access. This update then may be later destaged asynchronously to the DASD from either the cache or the NVS.
    Type: Grant
    Filed: December 30, 1991
    Date of Patent: February 1, 1994
    Assignee: International Business Machines Corporation
    Inventors: Jaishankar M. Menon, John E. Lindley, Robert W. Shomler