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OA62150: New Function - Provide z/OS Data Set File System (DSFS) support.


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APAR status

  • Closed as new function.

Error description

  • New Function - Provide Data Set File System (DSFS) support.

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED: z/OS Version 2 Release 5                     *
    *                 Data Set File System (DSFS)                  *
    *                 FMID(HZFS450)                                *
    * PROBLEM DESCRIPTION: To provide new function z/OS Data Set   *
    *                      File System (DSFS) support.             *
    * RECOMMENDATION: APPLY PTF                                    *
    New function is being introduced with this apar.
    z/OS Data Set File System Support Overview
    With z/OS Data Set File System (DSFS), z/OS UNIX applications
    can access data sets by presenting the data sets as a
    tree-structured file system that is mounted at mount point
    /dsfs in the z/OS UNIX file system tree. A utility file system
    is used by DSFS to contain POSIX information about the data
    sets accessed by applications to assist in the presentation of
    data sets as a tree in the z/OS UNIX file system space.
    Colony address space
    DSFS runs as a physical file system (PFS) in a z/OS UNIX colony
    address space. It cannot run inside the z/OS UNIX address space.
    For more information about colony address spaces, see "Running
    a physical file system in a colony address space" in z/OS UNIX
    System Services Planning.
    Supported data sets
    DSFS supports the following data sets:
     - Fixed and variable-length record physical sequential data
       sets (PS)
     - Partitioned data sets (PDS)
     - Partitioned data set extended (PDSE)
    DSFS does not support variable-spanned record data sets. It
    does not allow access to encrypted data sets unless the utility
    file system data set is also encrypted. DSFS supports only
    cataloged data sets. It does not support aliases or VSAM data
    sets and it will not show those data sets in its directory tree,
    which makes them inaccessible to DSFS users.
    Case sensitivity
    DSFS is a case-insensitive physical file system. File names and
    directory names are returned in lowercase. It also converts any
    input name to lowercase and stores it as lowercase. When DSFS
    interacts with the z/OS System through DFSMS, it converts the
    names to uppercase. When specifying names in the DSFS tree, use
    lowercase. If uppercase names are specified, unpredictable
    results can occur. For example, an ls command with a wildcard
    and uppercase characters will result in failed pattern matching.
    DSFS runs with the requesting application user credentials for
    all access to data sets. For those cases where DSFS might cache
    data to reduce access calls to data sets, DSFS will make
    specific SAF calls to verify that the user has the required
    authority for all accesses to cached data. DSFS does not use
    z/OS UNIX security protocols.
    Utility file system
    DSFS requires the administrator to define a linear data set by
    using the DEFINE CLUSTER command with the ZFS keyword to define
    a utility file system. This file system is used to store the
    directory tree that is used to represent the accessed data sets
    as a file system tree and will cache POSIX byte-stream
    representations of the data sets that are being read and
    written by applications. Each system in a shared file system
    will use its own utility file system for its processing. If the
    user defines a key label for the data set, then DSFS encrypts
    the data that it stores in the utility file system. DSFS also
    allows an option for transparent data compression of the files
    that it stores in its utility file system.
    Parameters file (IDFFSPRM)
    DSFS allows specification of a parameters file or allows for
    parmlib search to be used to specify parameters that control
    DSFS behavior. Many of these parameters can also be dynamically
    modified while DSFS is running.
    The dsadm commands
    DSFS provides commands that can query utility file system usage
    or statistics for a particular file or directory. Commands are
    also provided to enable the administrator to configure and
    monitor DSFS.
    After the receive/apply has been performed, configuration is
    needed to activate the DSFS function. Refer to Chapter 2.
    "Installing and configuring DSFS" in z/OS Data Set File
    System Administration (GI13-5603-50).
    Documentation updates:
    Two new publications are being added with this function. Refer
    to the following link to obtain these books:
    z/OS Data Set File System Administration (GI13-5603-50)
    The purpose of this document is to provide complete and detailed
    guidance and reference information. This information is used
    by system administrators who work with z/OS Data Set File
    System (DSFS).
    z/OS Data Set File System Messages and Codes (GI13-5604-50)
    Detailed explanations and recovery actions are provided to
    supplement the messages that are issued by Data Set File System
    (DSFS). Processing options that can be used to control DSFS are
    documented in z/OS Data Set File System Administration.

Problem conclusion

Temporary fix


APAR Information

  • APAR number


  • Reported component name


  • Reported component ID


  • Reported release


  • Status


  • PE




  • Special Attention

    YesSpecatt / New Function / Xsystem

  • Submitted date


  • Closed date


  • Last modified date


  • APAR is sysrouted FROM one or more of the following:

  • APAR is sysrouted TO one or more of the following:

    UJ08232 UJ08233



Publications Referenced

Fix information

  • Fixed component name


  • Fixed component ID


Applicable component levels

[{"Business Unit":{"code":"BU054","label":"Systems w\/TPS"},"Product":{"code":"SG19M"},"Platform":[{"code":"PF054","label":"z Systems"}],"Version":"450"}]

Document Information

Modified date:
06 July 2022