Software
     Product
     Description

     ________________________________________________________________

     PRODUCT NAME:  VAX Disk Striping Driver for VMS, Version 2.0 SPD
     31.66.01

     DESCRIPTION

     The VAX Disk Striping Driver implements disk striping for the
     VMS Operating System. The product provides the ability for users
     to create one or more stripesets, each comprised of two or more
     physical disk drives and represented to the user application
     (and operating system) as a single pseudo-device. Stripesets
     must be composed of disks of a single type. Full VAXcluster
     support is provided with Striping V2.0 (with VMS V5.4).

     Disk striping interleaves multiple disks to improve I/O per-
     formance in the same way that high-performance memory systems
     interleave memory banks. In each case, data requests are de-
     composed and distributed to physical storage components that
     process those requests in parallel.

     There are three types of I/O performance problems that disk
     striping can help relieve. They are:

     1. Applications that require very high data transfer rates

     2. Systems in which static disk load balancing is ineffective

     3. Applications that are prohibited from distributing data
        across multiple disks but need higher throughput than is
        available from a single disk




                                  DIGITAL                  April 1991

                                                          AE-NZ29B-TE

 


     VAX Disk Striping Driver for VMS, Version 2.0       SPD 31.66.01



     The pseudo-device responds to all of the I/O operations defined
     for ordinary disk drives including physical, logical, and vir-
     tual I/O. As a result, the striping driver is transparent to all
     VMS software other than diagnostics. However, a stripeset may
     not be a VMS boot or dump device, and BACKUPs must be done on
     the pseudo-device, not on the member units.

     A Digital Command Language (DCL) interface (CLI) is provided
     that enables the privileged user to define stripesets and to
     create and destroy the pseudo-devices that represent them. It
     also allows statistics and configuration information associated
     with the pseudo-devices to be listed.

     HARDWARE REQUIREMENTS

     VAX, MicroVAX, VAXstation, or VAXserver configuration as speci-
     fied in the System Support Addendum (SSA 31.66.01-x).

     SOFTWARE REQUIREMENTS

     For Systems Using Terminals (No DECwindows Interface):

     VMS Operating System

     Refer to the System Support Addendum (SSA 31.66.01-x) for avail-
     ability and required versions of prerequisite software.

     ORDERING INFORMATION

     Software Licenses: QL-YELA*-**
     Software Media: QA-YELA9-**
     Software Documentation: QA-YELAA-GZ
     Software Product Services: QT-YELA*-**

     *  Denotes variant fields. For additional information on avail-
        able licenses, services, and media, refer to the appropriate
        price book.


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     VAX Disk Striping Driver for VMS, Version 2.0       SPD 31.66.01



     SOFTWARE LICENSING

     This software is furnished under the licensing provisions of
     Digital Equipment Corporation's Standard Terms and Conditions.
     For more information about Digital's licensing terms and poli-
     cies, contact your local Digital office.

     LICENSE MANAGEMENT FACILITY SUPPORT

     This layered product supports the VMS License Management Facil-
     ity.

     License units for this product are allocated on a CPU-capacity
     basis.

     For more information on the License Management Facility, refer
     to the VMS Operating System Software Product Description (SPD
     25.01.xx) or the License Management Facility manual of the VMS
     Operating System documentation set.

     For more information about Digital's licensing terms and poli-
     cies, contact your local Digital office.

     SOFTWARE PRODUCT SERVICES

     A variety of service options are available from Digital. For
     more information, contact your local Digital office.

     SOFTWARE WARRANTY

     Warranty for this software product is provided by Digital with
     the purchase of a license for the product as defined in the
     Software Warranty Addendum of this SPD.






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     VAX Disk Striping Driver for VMS, Version 2.0       SPD 31.66.01




     [TM] The DIGITAL Logo, DECwindows, MicroVAX, VAX, VAXcluster,
          VAXft, VAXserver, VAXstation, and VMS are trademarks of
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