IBM Z Simplification

IBM Z Simplification

IBM Z Simplification

Transforming IBM Z into an simpler, more intuitive platform so every user, from beginners to experts, can learn faster, work confidently, and drive meaningful outcomes.

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  • 1.  Device Support Deprecations

    Posted 04/06/26 05:13 PM
    Edited by Sneha Kanaujia Fisher 07/28/26 09:40 AM
    Added 2026-07-28:

    Removal of Support for Select Devices and Control Unit Types

    What is being removed or changed

    z/OS 3.2 will be the last release to support a larger list of device and control unit types. After z/OS 3.2, these devices and control unit types will no longer directly connect to any in-service IBM Z or LinuxONE server or those that have previously been removed from service.

    Required customer migration or upgrade actions

    Remove any of the listed devices and control units from their I/O Definition File (IODF), especially for device types 3380, 3380A, and 3380B. These disks should be converted to devices of type 3390, 3390A, and 3390B, respectively, in their storage servers. See the full list of devices and control unit types that will no longer supported in the Statement of Direction (AD26-0808).

    IBM is planning an accommodation when removed select unit types are specified in batch JCL in order to reduce the upgrade impact of these device removals.

    Why is IBM making this change?

    These device and control unit types represent outdated hardware technologies that are no longer supported on modern IBM Z and LinuxONE systems. Removing support simplifies I/O configuration management and allows z/OS to focus on currently supported hardware technologies.

    Links to the relevant documentation

    z/OS Statement of Direction AD26-0808

    Added 2026-04-06:

    Removal of Support for MICR/OCR

    What is being removed or changed

    z/OS 3.2 is planned to be the last release to support MICR/OCR.

    Required customer migration or upgrade actions

    Identify and remove MICR/OCR dependencies; migrate to modern document processing solutions.

    Why is IBM making this change?

    MICR/OCR technology reflects specialized outdated device support that is no longer widely used. Removing support simplifies the platform and allows IBM to focus on current document processing technologies.

    Links to the relevant documentation

    z/OS 3.2 Announcement - Statement of Direction AD26-0005

    Change the Default Location for DASD and Tape Unit Control Blocks (UCBs)

    What is being removed or changed

    z/OS 3.2 is planned to be the last release where the default location for DASD and Tape UCBs is in 24-bit storage (LOCANY=NO).

    Required customer migration or upgrade actions

    Validate compatibility with 31-bit UCB storage and plan testing ahead of future releases.

    Why is IBM making this change?

    Moving away from 24-bit storage dependencies helps modernize the operating system and better utilize available memory resources.

    Links to the relevant documentation

    z/OS 3.2 Announcement - Statement of Direction AD26-0005

    Removal of Support for z/OS Discovery and Auto-Configuration (zDAC)

    What is being removed or changed

    z/OS 3.2 is planned to be the last z/OS release to support z/OS Discovery and Auto-Configuration (zDAC).

    The removal of zDAC affects some functions available through HCD panels, HCD batch invocations, and HCM. The Discovered new and changed control units and I/O devices HCD panel option will not propose any changes to your current IODF based on control units and I/O devices that have been sensed in your FICON SAN. The various HCD and HCM options to verify an active or target configuration against sensed data of FICON attached storage devices will no longer sense and provide comparison data. Similarly, information within the I/O path report available through HCD panels, an HCD batch job, or HCM that depend on data sensed from the attached FICON storage devices will no longer be included in the report.

    Required customer migration or upgrade actions

    Identify usage of zDAC discovery and verification functions and adjust HCD/HCM workflows accordingly.

    The ZOSMIG32_NEXT_IOS_DEPRECATIONS health check can be run on your z/OS 3.2, z/OS 3.1, or z/OS 2.5 system to identify whether zDAC related functions were performed during the current IPL.

    Why is IBM making this change?

    Hardware configuration management workflows have evolved and no longer require zDAC-specific discovery capabilities. Retiring zDAC reduces complexity in configuration management tooling.

    Links to the relevant documentation

    z/OS 3.2 Announcement - Statement of Direction AD26-0005

    z/OS 3.2 IBM Health Checker for z/OS User's Guide

    Removal of Support for Dynamic Channel‑Path Management (DCM)

    What is being removed or changed

    z/OS 3.2 is planned to be the last z/OS release in which IBM intends to support Dynamic Channel‑Path Management (DCM).

    With the removal of DCM, z/OS processing will no longer detect, manage, or display the current status of dynamic channel paths.

    Required customer migration or upgrade actions

    Customers should:

    •         Identify environments that use DCM
    •         Remove managed channel definitions
    •         Optionally replace managed dynamic channel paths with static CHPIDs based on capacity and availability requirements

    Using HCD, review your channel path and control unit definitions in the IODF. The channel path definitions use the Managed (Mgd) attribute to indicate whether the channel is managed and the I/O Cluster associated with it. Consider converting these to non-managed CHPIDs. On the control unit definitions, managed paths are indicated by specifying an asterisk (*) rather than a CHPID number. The asterisk should be removed and optionally replaced with static CHPIDs based on your capacity needs.

    The ZOSMIG32_NEXT_IOS_DEPRECATIONS health check can be run on your z/OS 3.2, z/OS 3.1, or z/OS 2.5 system to identify whether there were any managed CHPIDs defined or SETIOS commands issued to enable, disable, or refresh the Dynamic Channel-Path Management function during the current IPL.

    Why is IBM making this change?

    The value of DCM has diminished as hardware and operational practices have evolved. IBM is simplifying I/O management by retiring a specialized capability with limited adoption.

    Links to the relevant documentation

    z/OS 3.2 Announcement - Statement of Direction AD26-0005

    z/OS 3.2 IBM Health Checker for z/OS User's Guide

    Removal of Support for the Ability to Disable HYPERPAV Mode

    What is being removed or changed

    z/OS 3.2 is planned to be the last z/OS release to support disabling HyperPAV using HYPERPAV=NO.

    Required customer migration or upgrade actions

    Identify HYPERPAV=NO usage and validate DASD behavior under HyperPAV-only operation.

    The ZOSMIG32_NEXT_IOS_DEPRECATIONS health check can be run on your z/OS 3.2, z/OS 3.1, or z/OS 2.5 system to identify whether any explicit disablement of HyperPAV using the SETIOS command or IECIOSxx parmlib was performed during the current IPL.

    The ZOSMIG32_NEXT_IOS_PLIB_DEFAULTS health check can be run on your z/OS 3.2, z/OS 3.1, of z/OS 2.5 system to identify whether the system is running with the default HYPERPAV disablement, which would automatically enabled in future releases.

    Why is IBM making this change?

    HyperPAV is the strategic DASD access model and provides performance advantages over traditional PAV implementations. Removing the ability to disable HyperPAV helps standardize system behavior.

    Links to the relevant documentation

    z/OS 3.2 Announcement - Statement of Direction AD26-0005

    z/OS 3.2 IBM Health Checker for z/OS User's Guide



  • 2.  RE: Device Support Deprecations

    Posted 07/30/26 03:01 PM

    Regarding "Removal of Support for Select Devices and Control Unit Types". This seems to cause some confusion, especially the device type CTC. CTC is also acronym for Channel-to-Channel communication. z/OS does not deprecate CTC communication. FICON CTC communication will still be supported. In HCD this configures via FCTC control units and FCTC devices.

    CTC is also a device type in z/OS (HCD). These CTC devices were used to do CTC communication via ESCON channels. ESCON channels are deprecated for more than 10 year. Only this device type, and corresponding control unit types will be removed from the next z/OS release.

    Another discussion was about device type OSAD.  OSAD (OSA diagnostic device) devices have been a way to diagnose OSA Express adapters in the past. This functionality was available on IBM Z server until IBM z13. These machines are all out of service. The diagnostic capability has been moved to the HMC. OSAD devices can be removed from an IODF without loosing any functionality.



    ------------------------------
    Michael Grötzner
    z/OS I/O Configuration Architect
    IBM Germany Research & Development GmbH
    ------------------------------



  • 3.  RE: Device Support Deprecations

    Posted 08/05/26 09:08 AM

    Removal of Support for Select Devices and Control Unit Types

    If system encounters unsupported device types, what's the expected behavior during initialization?

    Removal of Support for Dynamic Channel‑Path Management (DCM)

    If we see the following message during initialization, we are not affected by this removal of functionality. Is this correct?

    IOS351I DYNAMIC CHANNEL PATH MANAGEMENT NOT ACTIVE

    Thanks!

    Shigeki



    ------------------------------
    Shigeki Kimura
    IBM Z Federated Advocate, zChampion
    IBM Japan
    ------------------------------



  • 4.  RE: Device Support Deprecations

    Posted 08/05/26 11:08 AM

    HI Shigeki,

    For the unsupported device types:  If you IPL the next z/OS release with any of the devices being unsupported in your z/OS software I/O configuration (Operating System configuration of type MVS in your IODF) you will see message "IEA521I devtype DEVICE TYPE NOT RECOGNIZED (num DEVICES)" during IPL. System initialization continues but the device are no longer available for use. 



    ------------------------------
    Marna Walle
    z/OS Installation and Upgrade
    IBM Poughkeepsie
    ------------------------------

    Original Message


  • 5.  RE: Device Support Deprecations

    Posted 08/05/26 11:09 AM

    Removal of Support for Dynamic Channel‑Path Management (DCM)

    If we see the following message during initialization, we are not affected by this removal of functionality. Is this correct?

    IOS351I DYNAMIC CHANNEL PATH MANAGEMENT NOT ACTIVE

    Hello Shigeki, yes that is correct.  Command D IOS,DCM can be used to show if DCM is active.  If that shows that IOS351I DYNAMIC CHANNEL PATH MANAGEMENT NOT ACTIVE, then you would not be affected by the removal of this functionality



    ------------------------------
    TABOR POWELSON
    ------------------------------

    Original Message


  • 6.  RE: Device Support Deprecations

    Posted 08/05/26 11:22 AM

    Removal of Support for Dynamic Channel‑Path Management (DCM)

    If we see the following message during initialization, we are not affected by this removal of functionality. Is this correct?

    IOS351I DYNAMIC CHANNEL PATH MANAGEMENT NOT ACTIVE

    Hello Shigeki, yes that is correct.  Command D IOS,DCM can be used to verify if DCM is active.  If it shows IOS351I DYNAMIC CHANNEL PATH MANAGEMENT NOT ACTIVE then you would not be affected by the removal of this functionality.



    ------------------------------
    TABOR POWELSON
    ------------------------------

    Original Message