International Business Machines Corporation

Joel Kenneth Lyman

Ralph Thomas Beeston

Erika Dawson

Jon Arthur Lynds

Gavin Stuart Johnson

Duke Andy Lee

Kirby Grant Dahman

Paul Merril Greco

Scott Milton Fry

David Luciani

Cory G Smith

Christopher Grunow

Spencer G Mower

Arthur W Stillwell

Wayne Erwin Rhoten

Kathryn Eileen Eldred

Harry M Yudenfriend

Wayne Charles Carlson

Various embodiments of a tape storage system having a physical control unit configured to support multiple logical control units are provided. Each logical control unit supports communication with a single tape drive model type up to a maximum number of drives. A customer obtains a number N of logical control units through purchase, lease or other legitimate avenues. Based on the number of tape drive model types L and the number of tape drives for each type Q, the model types are mapped to the N LCUs. In general, mapping priority is given to the newer generation model types and the model types in which the number of attached tape drives Qexceeds the capacity M of a single LCU.

Configuration of a physical control unit to support multiple logical control units for different tape drive types in a mainframe native tape attachment storage system

A tape storage system having a physical control unit configured to support multiple logical control units is provided. Each logical control unit supports communication with a single tape drive model type up to a maximum number of drives. A customer obtains a number N of logical control units through purchase, lease or other legitimate avenues. Based on the number of tape drive model types L and the number of tape drives for each type Q, the model types are mapped to the N LCUs. In general, mapping priority is given to the newer generation model types and the model types in which the number of attached tape drives Qexceeds the capacity M of a single LCU. An exception being that the oldest model type is ensured a mapping to an LCU. The LCUs may be reconfigured and the model types remapped on the physical CU if the customer adds different model types to the storage system or obtains a different number of LCUs.

In one embodiment, a product includes a magnetic medium having written thereon data in a data track. The data includes encrypted data written over unencrypted data. An indicator of a physical position on the magnetic medium that corresponds to an end of the encrypted data is stored on the product. A product according to another embodiment includes a magnetic medium having written thereon data in a data track. The data includes encrypted data written over unencrypted data. A portion of the unencrypted data is located before the encrypted data on the medium. An indicator of a physical position on the magnetic medium that corresponds to a beginning of the encrypted data is stored on the product.

Monitoring of residual encrypted data to improve erase performance on a magnetic medium

In one embodiment, a system includes a processor and logic integrated with and/or executable by the processor, the logic being configured to: determine a physical position on a magnetic medium that corresponds to an end of an encrypted data set; store an indicator of the physical position on the magnetic medium and/or a memory coupled thereto; and cause obscuring of an unencrypted data set positioned after the physical position without overwriting the encrypted data set. In another embodiment, a computer program product includes a computer readable storage medium and program instructions embodied therewith, the program instructions readable and/or executable by the processor to cause the processor to: read an indicator of a physical position on a magnetic medium that corresponds to an end of an encrypted data set; and cause obscuring of an unencrypted data set positioned after the physical position without overwriting the encrypted data set.

Method embodiments for facilitating configuration of a physical control unit to support multiple logical control units are provided. Each logical control unit supports communication with a single tape drive model type up to a maximum number of drives. A customer obtains a number N of logical control units through purchase, lease or other legitimate avenues. Based on the number of tape drive model types L and the number of tape drives for each type Q, the model types are mapped to the N LCUs. In general, mapping priority is given to the newer generation model types and the model types in which the number of attached tape drives Qexceeds the capacity M of a single LCU. An exception being that the oldest model type is ensured a mapping to an LCU. The LCUs may be reconfigured and the model types remapped on the physical CU if the customer adds different model types to the storage system or obtains a different number of LCUs.

A method according to one embodiment includes outputting a first alert when a cache free space size is less than a first threshold and entering into a warning state, and outputting a second alert when the cache free space size is less than a second threshold and entering into a critical state. At least one scratch volume is deleted when in the critical state, the scratch volume chosen based on at least one of: a length of time the scratch volume has been designated scratch, a priority level of the information stored on the scratch volume, and a scratch delay value associated with the scratch volume.

Managing a cache in a multi-node virtual tape controller

According to one embodiment, a system includes a virtual tape library having a cache, a virtual tape controller (VTC) coupled to the virtual tape library, and an interface for coupling multiple hosts to the VTC. The cache is shared by the multiple hosts, and a common view of a cache state, a virtual library state, and a number of write requests pending is provided to the hosts by the VTC. In another embodiment, a method includes receiving data from at least one host using a VTC, storing data received from all the hosts to a cache using the VTC, sending an alert to all the hosts when free space is low and entering into a warning state, sending another alert to all the hosts when free space is critically low and entering into a critical state while allowing previously mounted virtual drives to continue normally.

According to one embodiment, a method for managing cache space in a virtual tape controller includes receiving data from at least one host using the virtual tape controller; storing data received from the at least one host to a cache using the virtual tape controller; sending a first alert to the at least one host when a cache free space size is less than a first threshold and entering into a warning state using the virtual tape controller; sending a second alert to the at least one host when the cache free space size is less than a second threshold and entering into a critical state using the virtual tape controller; and allowing previously mounted virtual drives to continue normal writing activity when in the critical state.

Methods for managing a cache in a multi-node virtual tape controller

In one embodiment, a system includes a processor, logic in the processor and/or memory configured to determine a physical position on a magnetic medium that corresponds to an end of encrypted data written over residual unencrypted data, and logic configured to store an indicator of the physical position on at least one of the magnetic medium and a memory coupled thereto. In another embodiment, a method includes determining a physical position on a magnetic medium that corresponds to an end of encrypted data written over residual unencrypted data, storing an indicator of the physical position on at least one of the magnetic medium and a memory coupled thereto.

According to one embodiment, a system includes a virtual tape library having a cache, a virtual tape controller (VTC) coupled to the virtual tape library, and an interface for coupling at least one host to the VTC. The cache is shared by all the hosts, and a common view of a cache state, a virtual library state, and a number of write requests pending is provided to all the hosts by the VTC.

Systems for managing a cache in a multi-node virtual tape controller

A system according to one embodiment includes a processor; logic in the processor and/or a memory configured to determine a furthest physical position on a magnetic medium that unobscured data has been written to; and logic configured to store an indicator of the furthest physical position on at least one of the magnetic medium and a memory coupled thereto. A system according to another embodiment includes a processor; logic in the processor and/or a memory configured to receive an instruction to obscure data on a magnetic medium; logic configured to read an indicator of a furthest physical position on the magnetic medium that unobscured data has been written to; and logic configured to cause obscuring of the unobscured data on the magnetic medium, and terminating the obscuring upon reaching the physical position in the indicator.

Monitoring of extent of writing of unobscured data to improve erase performance on a magnetic medium

Reuse of partially expired physical tape volumes reuse is attained in a longitudinal tape data storage drive, wherein data is stored as a sequence of serpentine wraps, a wrap comprising a first linear path traced on a longitudinal tape; and another linear path, laterally spaced from the first linear path, traced on the longitudinal tape; the linear paths extending from one end of the longitudinal tape to the opposite end and arranged in opposite directions. One embodiment of a method comprises identifying expired portions of stored data on the longitudinal tape; determining whether data of a complete linear path of the longitudinal tape has been expired; and allowing reuse of any determined complete linear path for storage of data.

Reuse of partially expired physical tape volume

A data storage and retrieval system is disclosed which includes encoded information regarding known valid system configurations, nominal performance specifications for various I/O devices, and nominal performance specifications for various interconnecting communication buses. A method is disclosed to validate the apparent configuration of the data storage and retrieval system. A method is disclosed to evaluate the performance of each I/O device and interconnecting bus disposed within the data storage and retrieval system.

Method to validate system configuration in a data storage and retrieval system

Provided are a method, system, and article of manufacture to process communications between a host and storage drive having a storage media. An Input/Output (I/O) request is received from the host directed to the storage media that requires requested information be sent to the storage drive to use to execute the I/O request against the storage media. A message is sent to the host to cause the host to modify I/O timeout operations in response to determining that the requested information is required.

Modifying host input/output (I/O) activity to allow a storage drive to which I/O activity is directed to access requested information

The present invention provides fast read performance for accessing a file from a multiplicity of files when its corresponding Block ID is unavailable, by furnishing new file-positioning commands, allowing access to data based on File Number, at the same fast locate speed as with Block Ids, thereby expanding the range of applications that can use certain tape drive systems effectively. The present invention includes both a device architecture for supporting the file oriented positioning and the appending, as well as a software system that can permit easy application access to the device facilities and system components which permit the advantages to accrue without any software application or operator changes, including a robust architecture for navigating residual data, e.g., for data recovery. The present invention comprises several device command innovations, a relative positioning command, an absolute positioning command, and other commands, e.g., for sensing current position.

Growing community of inventors

Tucson, AZ, United States of America

Joel Kenneth Lyman