• • Abstract for MVS Programming: Authorized Assembler Services Guide
  • Summary of changes
    • Summary of changes for z/OS Version 2 Release 1 (V2R1) as updated February 2015
    • Summary of changes in z/OS Version 2 Release 1 (V2R1), as updated December 2013
    • z/OS Version 2 Release 1 summary of changes
• Introduction
• Subtask creation and control
  • Creating a new task (ATTACH or ATTACHX macro)
  • Ensuring that a process completes (STATUS macro)
  • Communicating with a program (EXTRACT, QEDIT)
    • Providing an EXTRACT answer area
• Program management
  • Residency and addressing mode of programs
    • Placement of modules in storage
    • Addressing mode
  • Specifying where the module is to be loaded (LOAD macro)
  • Synchronous exits (SYNCH or SYNCHX macro)
  • Using checkpoint/restart
  • Using re-entrant modules
  • Using LLACOPY to refresh LLA directories
  • Changing the LNKLST concatenation
    • Changing the current LNKLST set
  • Monitoring dynamic LPA processing
    • Listing contents of dynamic LPA with CSVDLPAU
      • Invoking CSVDLPAU
        • CSVD002W
• Serialization
  • Choosing a serialization service
  • Providing ENQ resource information on DISPLAY GRS command
  • Locking
    • Categories of locks
    • Types of locks
      • Examples of lock types
    • Locking hierarchy
    • CML lock considerations
    • Obtaining, releasing, and testing locks (SETLOCK)
      • Disabled/enabled state for obtain
      • Disabled/enabled state for release
    • Suspend lock instrumentation data
  • Using the must-complete function (ENQ/DEQ)
    • Characteristics of the must-complete function
    • Programming notes
  • Shared direct access storage devices (shared DASD)
    • Volume/device status
    • Volume handling
    • Macros used with shared DASD (RESERVE, EXTRACT, GETDSAB)
      • Releasing devices
      • Preventing interlocks
      • Timing contention
      • Volume assignment
      • Program libraries
      • Using different serialization techniques for the same volume
      • Finding the UCB address for the RESERVE macro
        • Using the GETDSAB macro to find the UCB address
          • Procedures
        • Using the IEFDDSRV macro to find the UCB address
          • Procedures
        • Using the EXTRACT macro to find the UCB address
          • Procedures
        • Using the DEB and the DCB to find the UCB address
          • Procedures
        • RESDEQ subroutine using IEFDDSRV
  • Serializing parallel tasks (WAIT and POST)
    • Asynchronous cross memory POST
      • When LINKAGE=SYSTEM is not specified
      • When LINKAGE=SYSTEM is specified
    • Synchronous cross memory post
    • Bypassing the POST routine
    • Waiting for event completion (EVENTS)
  • Writing POST exit routines
    • Identifying and deleting exit routines
    • Initializing extended ECBs and ECB extensions
    • POST interface with exit routines
    • Re-entry to POST from a POST exit
  • Branch entry to the POST service routine
  • Branch entry to the WAIT service routine
  • Serializing RB processing
    • Suspending an RB until an event completes (SUSPEND)
      • Scenario 1:
      • Scenario 2:
      • Considerations when suspending an RB
        • General considerations
        • RB=PREVIOUS considerations
        • RB=CURRENT considerations
    • Using the CALLDISP macro
    • Resuming execution of a suspended RB
  • Synchronizing unit of work (tasks or SRBs)
    • Pause elements and pause element tokens
    • Using the services
    • PE ownership and cleanup
  • Global resource serialization latch manager
    • Overview
    • How to use the callable services
  • Planning to use the latch manager callable services
    • Including a latch manager interface definition file (IDF)
    • Loading the linkage assist routines
    • Providing recovery for the latch manager
      • Steps for providing recovery for the latch manager
      • FRR tasks
        • Program mainline example
      • FRR example
  • Guide to the latch manager callable services
    • Creating a latch set (ISGLCRT and ISGLCR64 services)
      • Specifying the number of latches in a latch set
      • Identifying latch sets
    • Specifying a latch's identity or usage
    • Obtaining a latch (ISGLOBT and ISGLOB64 services)
      • Specifying the number of a requested latch
      • Specifying an obtain option
      • Summary of results of calls to Latch_Obtain
    • Releasing a latch (ISGLREL and ISGRE64 services)
      • Specifying a release option
      • Summary of results of calls to Latch_Release
    • Purging one or more latches (ISGLPRG and ISGLPR64 services)
    • Purging one or more latches in a group of latch sets for a group of requestors (ISGLPBA and ISGLPB64 services)
      • Purging groups of latch sets
• Reporting system characteristics
  • Collecting information about resources and their requestors (ISGQUERY and GQSCAN macros)
    • How GQSCAN returns resource information
      • How area size determines the information GQSCAN returns
      • How scope and token values determine the information GQSCAN returns
    • How global resource serialization determines the scope of an ENQ or RESERVE request
  • Using the SRM reporting interface to measure subsystem activity
  • Obtaining dispatchability data about address spaces (IEAMRMF3 macro)
• Tracing applications using component trace
  • Planning an application trace
    • Trace activities
    • Executable macros for component tracing
    • Operator commands for component tracing
    • IPCS subcommands for component tracing
    • Exit routines for component tracing
    • Data areas and mapping macros for component tracing
    • Parmlib members for component tracing
    • When to trace
    • Where and what to trace
    • Creating trace buffers
    • Using multiple traces
    • Setting up user-defined options
    • Starting, stopping and changing the trace
    • Using parmlib members
    • Externalizing trace data in a dump
    • Externalizing trace data through the external writer
  • Coding macros for application traces
    • Using the CTRACE macro to define the application to component trace
    • Using CTRACECS to manage trace buffer status
    • Deleting the application from component trace
  • Coding a start/stop exit routine
    • Exit routine environment
    • Exit routine processing
    • Programming considerations
    • Start/stop exit routine communications
    • Entry specifications
    • Return specifications
  • Coding a display trace exit routine
    • Exit routine environment
    • Exit routine processing
    • Programming considerations
    • Exit routine communications
    • Entry specifications
    • Return code specifications
  • Creating trace entries
    • Understanding the fields in a CTE
    • Organizing variable data in CTEs
• Communication
  • Interprocessor communication
  • Writing and Deleting Messages (WTO, WTOR, and DOM Macros)
    • Routing the Message
    • Altering Message Text
    • Writing a Multiple-Line Message
    • Embedding Label Lines in a Multiple-Line Message
    • Issuing a Message and Loading a Wait State (WTO and LOADWAIT Macros)
    • Using the Wait State Macro (LOADWAIT)
    • Non-restartable and Restartable Wait States
    • Invoking the LOADWAIT Macro
      • Example with All Wait State Information Known at Assembly Time
      • Example with Wait State Information Not Known at Assembly Time
    • Deleting Messages Already Written
    • Writing to the System Log
  • Issuing an internal START or REPLY command (MGCR)
  • Issuing operator commands from a program (MGCRE macro)
  • Issuing a command response message
    • Rules for a command response WTO
    • Old code conversion
    • Where to get the information
      • CIB control block (mapped by IEZCIB)
      • CSCB control block (mapped by IEECHAIN)
      • CMDX control block (mapped by IEZVX101)
      • SSCM control block (mapped by IEFSSCM)
    • Assembler example with CIB control block
    • Assembler example with CMDX control block, multi-line WTO
  • Controlling command flooding (IEECMDS macro)
  • Routing commands in a sysplex (CPF macro)
    • Assigning a prefix
    • Persistence of the prefix
  • What is an extended MCS console?
    • Activating an extended MCS console
      • Specifying console attributes
      • Storing messages directed to an extended MCS console
      • Controlling message traffic directed to an extended MCS console
    • Receiving messages and command responses, and issuing commands
      • Receiving messages and command responses
        • What is the message data block (MDB)
      • Receiving the hardcopy message set
      • Issuing commands
      • What to do if message queuing stops
    • Deactivating extended MCS consoles
      • Switching to another console
    • Removing extended MCS consoles
    • Example of managing an extended MCS console session
• Listening for system events
  • Establishing a listen request
    • Qualifying events
      • QUAL example
    • nn filtering events
  • Coding the listener user exit routine
    • Non-SRBEXIT routine
    • SRBEXIT routine
  • Passing parameters to a listener user exit routine
  • Ending the listener user exit routine
  • ENF event codes and meanings
  • ENF sample programs
    • SMFLSTEN - Sample ENF listener
      • Issue listen request without qualifier
      • Issue listen request with QUAL=ENF37Q00
      • Sample ENFREQ DELETE request
      • Module declarations
      • SMFLSTAL - Sample ENF listener user exit routine
      • Module declarations
      • SMFLST00 - Sample ENF listener user exit routine
  • Listening for global resource serialization-related system events
    • Monitoring contention changes
      • Listening for RNL change data
      • Listening for other global resource serialization events
• Using a service request block (SRB)
  • What is an SRB?
  • Why would you use an SRB?
  • Scheduling and managing SRBs
  • Specifying the addressing environment of the SRB routine
    • Using the ENV parameter on IEAMSCHD
    • Using the MODE parameter on SCHEDULE
  • Characteristics and restrictions of SRB routines
    • Implications of running in SRB mode
    • Environment of the SRB routine at entry
  • Scheduling an SRB (IEAMSCHD or SCHEDULE macro)
    • Scheduling an SRB using IEAMSCHD
    • Scheduling an SRB using SCHEDULE
      • Initializing the SRB
  • Purging an SRB (PURGEDQ macro)
    • Identifying the SRB to be purged
    • The resource manager termination routine (RMTR)
    • Scenario of scheduling and purging an SRB
      • Example 1
      • Example 2
  • Serializing SRB processing
    • Suspending an SRB until an event completes (SUSPEND macro)
      • Suspend exit routine
    • Resuming or purging a suspended SRB (RESUME macro)
    • Scenario of suspending and resuming an SRB
    • Recovery responsibilities for a suspended SRB
  • Terminating a preemptable SRB
  • Calling an SRB to run synchronously
  • Transferring control for SRB processing (TCTL macro)
• Virtual storage management
  • Allocating and freeing virtual storage (GETMAIN, FREEMAIN and STORAGE macros)
    • Comparison of GETMAIN/FREEMAIN macros with the STORAGE macro
    • Specifying branch entry to GETMAIN and FREEMAIN services
    • Obtaining storage in another address space
    • Obtaining and using disabled reference (DREF) storage
  • Using cell pool services (CPOOL macro)
  • Selecting the right subpool for your virtual storage request
    • Program authorization
      • Selecting private or common storage
      • Managing private storage allocation
      • Selecting fetch protected or non-fetch protected storage
      • Selecting the storage key
      • Selecting pageable, DREF, or fixed storage
      • Selecting storage persistence
        • Selecting central storage backing
        • Additional considerations
        • Making the final selection
        • The subpool table
  • Tracking virtual storage allocation (CPOOL BUILD, GETMAIN, and STORAGE OBTAIN macros)
  • Obtaining information about the allocation of virtual storage (VSMLIST)
    • Using the VSMLIST work area
      • Allocated storage information
      • Free space
      • Unallocated storage information
  • Using IARQD — The page status interface routine
    • Decide which entry point you want to use
    • Obtain storage and load register 1
      • IARQDUMP
      • IARQDSPD
      • The delimiter page
    • Use NUCLKUP to find the address of the entry point you want to use
      • Example
      • Input register information
    • Invoke the entry point
• Accessing the scheduler work area
  • Using the IEFQMREQ and the SWAREQ macros
    • The SWAREQ macro
    • How to invoke SWAREQ
      • SWAREQ summary
      • Example of using SWAREQ
      • Return codes and reason codes from SWAREQ
        • UNAUTH=YES
        • UNAUTH=NO
    • The IEFQMREQ macro
      • How to invoke IEFQMREQ
      • Example of using IEFQMREQ
      • Return codes and reason codes from IEFQMREQ
• The virtual lookaside facility (VLF)
  • Deciding when to use VLF
  • Planning to use VLF
    • Data objects and classes
      • Private data sets
      • Cross-system sharing
      • When VLF notification is automatic
      • When VLF notification is not automatic
    • Data integrity
    • Recovery
  • Using the VLF macros
    • Defining a class of VLF objects
    • Identifying an end user to VLF
    • Retrieving a VLF object
    • Creating a VLF object
      • Using REPLACE
    • Notifying VLF of a change
    • Removing a VLF end user
    • Purging a VLF class
    • Modifying VLF
• Data-in-virtual
  • When to use data-in-virtual
    • Factors affecting performance
    • Creating a linear data set
  • Using the services of data-in-virtual
    • Identify
    • Access
    • Map
    • Save, Savelist, and Reset
    • Unmap
    • Unaccess
    • Unidentify
  • The IDENTIFY service
  • The ACCESS service
  • The MAP service
  • The SAVE service
  • The SAVELIST service
  • The RESET service
    • Effect of RETAIN mode on RESET
  • The UNACCESS and UNIDENTIFY services
  • Sharing data in an object
  • DIV macro programming examples
    • Executing an application
    • Processing a data-in-virtual object
• Sharing application data (name/token callable services)
  • Levels for name/token pairs
    • Determining what your program can do with name/token pairs
  • Checking authorization when retrieving a token
  • Deciding what name/token level you need
    • Primary-level name/token pair
    • System-level name/token pair
  • Owning and deleting name/token pairs
    • Example of using the name/token services
• Processor storage management
  • Fixing/freeing virtual storage contents
  • Protecting a range of virtual storage pages
  • PGFIX/PGFREE completion considerations
  • Input to page services
    • Virtual subarea list (VSL)
    • Page service list (PSL)
    • Short page service list (SSL)
  • Branch entry to page services
    • Cross memory mode
    • Non-cross memory mode
• Sharing data in virtual storage (IARVSERV macro)
  • Understanding the concepts of sharing data with IARVSERV
  • Storage you can use with IARVSERV
  • Obtaining storage for the source and target
  • Defining storage for sharing data and access
  • Changing storage access
  • How to share and unshare data
  • Accessing data in a sharing group
  • Example of sharing storage with IARVSERV
  • Use with data-in-virtual (DIV macro)
  • Use with page services (PGSER macro)
  • Diagnosing problems with shared data
  • Converting a central to virtual storage address (IARR2V macro)
• The nucleus
  • Linking to routines in the DAT-OFF nucleus (DATOFF)
    • Using system provided DAT-OFF routines (DATOFF)
      • INDMVCL0 and INDMVCL64 - Move character long
      • INDMVCLK and INDMVCL64 - Move character long in user key
      • INDXC0 and INDXC64 - Exclusive OR
      • INDCDS and INDCDS64 - Compare double and swap
    • Writing user DAT-OFF routines
    • Placing user DAT-OFF routines in the DAT-OFF nucleus
  • Obtaining information about CSECTs in the DAT-ON nucleus (NUCLKUP)
  • Customizing the nucleus region
    • The NMLDEF macro
    • Removing existing routines from IEANUC0x
• Providing recovery
  • Understanding general recovery concepts
    • Deciding whether to provide recovery
    • Understanding errors in MVS
    • Understanding recovery routine states
    • Understanding the various routines in a recovery environment
      • Mainline routine
      • Recovery routine
      • Retry routine
      • Resource manager
    • Choosing the appropriate recovery routine
      • Choosing an ESTAE-type recovery routine
      • Choosing an FRR
      • Floating point implications
      • Summary of recovery routine states
    • Understanding recovery routine options
    • Understanding how routines in a recovery environment interact
  • Writing recovery routines
    • Understanding what recovery routines do
      • Saving the return address to the system
      • Checking for the SDWA
      • Establishing addressability to the parameter area
      • Checking important fields in the SDWA
      • Checking the contents of the parameter area
      • Saving serviceability data
      • Recording in the Logrec data set
      • Requesting a dump
      • Correcting or minimizing the error
      • Deciding to retry or percolate
        • Recovery routines that retry
        • What the retry routine does
        • Recovery routines that percolate
    • Understanding the means of communication
      • Setting up, passing, and accessing the parameter area
        • Deciding what to include in the parameter area
        • Passing the parameter area
        • Accessing the parameter area
      • Using the SDWA
        • Updating the SDWA
        • Recording the SDWA in the logrec data set
        • Using the SETRP macro to update the SDWA
        • Symptom data required in the SDWA for dump suppression
        • Important fields in the SDWA
    • Special considerations for ESTAE-type recovery routines
      • RB considerations
      • Linkage stack considerations
        • Recovery routine
        • Retry routine
        • Deactivating an ESTAE-type recovery routine
      • Outstanding I/Os at the time of failure
      • Additional considerations specific to ESTAE-type recovery routines
      • Using ARRs
    • Special considerations for FRRs
  • Understanding the recovery environment
    • Register contents
      • Register contents on entry to a recovery routine
      • Register contents on return from a recovery routine
      • Register contents on entry to a retry routine
        • Retry from an ESTAE-type recovery routine
        • Retry from an FRR
    • Other environmental factors in recovery
      • Environment on entry to an ESTAE-type recovery routine
        • Authorization
        • SDWA storage key
        • Dispatchable unit mode
        • Cross memory mode
        • AMODE
        • ASC mode
        • Interrupt status
        • DU-AL
        • Locks
        • Program mask
        • Condition of the linkage stack
        • AX
        • EAX
        • Restricted environments
      • Environment on entry to a retry routine from an ESTAE-type recovery routine
        • Authorization
        • SDWA storage key
        • Dispatchable unit mode
        • Cross memory mode
        • AMODE
        • ASC mode
        • Interrupt status
        • DU-AL
        • Locks
        • Program mask
        • Condition of the linkage stack
        • AX
        • EAX
      • Summary of environment on entry to an ESTAE-type recovery routine and its retry routine
      • Environment on entry to an FRR
        • Authorization
        • SDWA storage key
        • Dispatchable unit mode
        • Cross memory mode
        • AMODE
        • ASC mode
        • Interrupt status
        • DU-AL
        • Locks
        • Program mask
        • Condition of the linkage stack
        • AX
        • EAX
        • Summary of environment on entry to an FRR
        • Restricted environments
      • Environment on entry to a retry routine from an FRR
        • Authorization
        • SDWA storage key
        • Dispatchable unit mode
        • Cross memory mode
        • AMODE
        • ASC mode
        • Interrupt status
        • DU-AL
        • Locks
        • Program mask
        • Condition of the linkage stack
        • AX
        • EAX
      • Linkage stack at time of retry
  • Understanding recovery through a coded example
  • Understanding advanced recovery topics
    • Providing recovery with minimal processor overhead (FESTAE macro)
    • Invoking RTM
      • Using the CALLRTM macro
        • TYPE=ABTERM
        • TYPE=MEMTERM
        • TYPE=SRBTERM
      • Using the ABEND macro
    • Providing multiple recovery routines
      • Percolation for the same unit of work
      • SRB-to-task percolation
    • Providing recovery for recovery routines
    • Providing recovery for multitasking programs
    • Using resource managers
      • Resource manager execution environment
        • Environment for ROUTINE=(BRANCH,routine)
        • Environment for ROUTINE=(LINK,routine)
        • Environment for ROUTINE=(PC,routine)
      • Installation-written resource managers
      • Adding an installation-written resource manager
        • Dynamically
        • At IPL
      • The resource manager parameter list
      • Register use
      • Processing sequence
  • Using STAE/STAI routines
• Processing program interruptions (SPIE, ESPIE)
  • Interruption types
• Dumping virtual storage (SDUMPX, SDUMP, and IEATDUMP macros)
  • SVC dumps
    • Deciding when to request an SVC dump
    • Understanding the type of SVC dump that MVS produces
    • Coding parameters that produce a synchronous dump
    • Designing a program to handle a synchronous dump
    • Coding parameters that produce a scheduled dump
    • Designing a program to handle a scheduled dump
    • Synchronizing your program through an ECB or SRB
    • Designing your program to run asynchronously with dump processing
    • Identifying the data set to contain the dump
    • Defining the contents of the dump
    • Identifying the address spaces or data spaces to be dumped
    • Customizing the contents of the SVC dump
    • Requesting the summary dump
    • Suppressing SVC dumps that duplicate previous SVC dumps
    • Providing symptom information through the SDUMPX macro
    • Requesting dumps on other systems in a sysplex
    • Using dynamic exits to control dumps in a sysplex
    • IEASDUMP.QUERY dynamic exit
      • Installing IEASDUMP.QUERY
      • IEASDUMP.QUERY dynamic exit environment
      • IEASDUMP.QUERY dynamic exit recovery
      • IEASDUMP.QUERY dynamic exit processing
      • Registers at entry to IEASDUMP.QUERY dynamic exit
      • Parameter area at entry to IEASDUMP.QUERY dynamic exit
      • Registers at exit from IEASDUMP.QUERY dynamic exit
      • Disassociating IEASDUMP.QUERY
    • IEASDUMP.GLOBAL and IEASDUMP.LOCAL dynamic exits
      • Installing IEASDUMP.GLOBAL and IEASDUMP.LOCAL
      • IEASDUMP.GLOBAL and IEASDUMP.LOCAL dynamic exit environment
      • IEASDUMP.GLOBAL and IEASDUMP.LOCAL dynamic exit
      • IEASDUMP.GLOBAL and IEASDUMP.LOCAL dynamic exit processing
      • Registers at entry to IEASDUMP.GLOBAL or IEASDUMP.LOCAL dynamic exit
      • Parameter area at entry to IEASDUMP.GLOBAL or IEASDUMP.LOCAL dynamic exit
      • Registers at exit from IEASDUMP.GLOBAL or IEASDUMP.LOCAL dynamic exit
      • Disassociating IEASDUMP.GLOBAL and IEASDUMP.LOCAL
    • IEASDUMP.SERVER dynamic exit
      • Installing IEASDUMP.SERVER
      • IEASDUMP.SERVER dynamic exit environment
      • IEASDUMP.SERVER dynamic exit recovery
      • IEASDUMP.SERVER dynamic exit processing
      • Registers at entry to IEASDUMP.SERVER dynamic exit
      • Parameter area at entry to IEASDUMP.SERVER dynamic exit
      • Registers at exit from IEASDUMP.SERVER dynamic exit
      • Disassociating IEASDUMP.SERVER
  • Transaction dumps
    • Deciding when to request a transaction dump
    • Understanding the type of transaction dump that MVS produces
    • Identifying the data set to contain the dump
    • Defining the contents of the dump
    • Customizing the contents of the transaction dump
    • Requesting the summary dump
    • Suppressing transaction dumps that duplicate previous transaction dumps
    • Providing symptom information through the IEATDUMP macro
    • Requesting dumps of other systems
• Protecting the system
  • System integrity
    • Documentation on system integrity
    • Installation responsibility
    • Elimination of potential integrity exposures
      • User-supplied addresses for user storage areas
      • User-supplied addresses for protected control blocks
      • Resource identification
      • SVC routines calling SVC routines
      • Control program and user data accessibility
      • Fetch protection provided for the PSA
      • Control program extensions
  • Authorized programs
  • Using APF to restrict access to system functions
    • Guidelines for using APF
    • APF-authorized libraries
    • APF-authorized library list
    • Requesting APF list services (CSVAPF macro)
    • Restricting the use of SVC routines
    • Restricting load module access
    • Assigning APF authorization to a load module
    • Overriding an authorization code - SETCODE statement
    • Authorization results under various conditions
  • Resource Access Control Facility (RACF)
  • System Authorization Facility (SAF)
    • MVS router
      • MVS router exit
    • Interface to the MVS router (RACROUTE)
      • Defining a resource (RACROUTE REQUEST=DEFINE)
      • Identifying a user (RACROUTE REQUEST=VERIFY and REQUEST=VERIFYX)
        • RACROUTE REQUEST=VERIFY
        • RACROUTE REQUEST=VERIFYX
      • Checking resource authorization (RACROUTE REQUEST=AUTH and REQUEST=FASTAUTH)
        • RACROUTE REQUEST=AUTH
        • RACROUTE REQUEST=FASTAUTH
      • Retrieving and encoding data (RACROUTE REQUEST=EXTRACT)
      • Building in-storage profiles (RACROUTE REQUEST=LIST)
      • Checking auditing options (RACROUTE REQUEST=AUDIT)
      • Checking user authority (RACROUTE REQUEST=DIRAUTH)
    • SAF interface to an external security product
      • Requirements for the external security product router
      • Input parameters to the external security product router
      • Return and reason codes from the external security product router
      • Programming considerations
  • Using the command authorization service
    • Command resource names
      • Syntax
      • Examples
  • Changing system status (MODESET)
    • Generating an SVC
    • Generating inline code
• Exit routines
  • Using asynchronous exit routines
    • Using the SCHEDIRB macro to initialize and schedule an IRB
    • Using the SCHEDIRB macro to schedule an IRB
    • Using the CIRB macro to initialize an IRB
    • Using the SCHEDXIT macro to schedule an IRB
    • System processing to run an asynchronous exit
      • Linkage stack considerations for asynchronous exit routines
  • Establishing a timer disabled interrupt exit
    • DIE characteristics
      • Exit from the DIE routine
      • DIE execution
    • Timer queue element control
      • Obtaining and freeing the TQE
      • Serializing the use of each TQE
      • Clock failure
      • Interval cancellation
  • Using dynamic exits services
    • CSVDYNEX terminology
    • Vector Register protocol for user exits
    • Defining an exit
      • FASTPATH processing
      • Removing the definition of an exit
    • Calling an exit routine or routines
      • Floating point protocol for user exits
      • Ensuring that exit routines exist at the CALL
      • Returning information from multiple exit routines
        • Merging return codes
      • Recovery for the CALL request
        • Recovery for exit routines with FASTPATH processing
    • Associating an exit routine with an exit
      • Ensuring that exit routines exist at the time of the association
      • Deleting an exit routine from an exit
• User-written SVC routines
  • Writing SVC routines
    • Type 6 SVC routines
    • Non-preemptable SVC routines
    • Programming conventions for SVC routines
  • Inserting SVC routines into the control program
    • Standard SVC routines
      • Example of adding user SVC routines to system libraries
      • Modifying the SVC table at execution time (SVCUPDTE macro)
      • Intercepting an SVC routine
    • Extended SVC routines
  • Subsystem SVC screening
• Accessing unit control blocks (UCBs)
  • Scanning for UCBs
  • Obtaining UCB addresses
    • UCB Common Segment
    • UCB Common Extension
    • UCB Prefix Extension
    • UCB Prefix Area
    • UCB details
  • Ensuring that UCBs are not deleted
    • Pinning and unpinning UCBs
    • When pinning is required
      • Example: Pinning an unallocated and offline device
      • Example: Passing an UCB address between asynchronously running programs
    • When pinning is not required
      • Example: Allocating a device
  • Requesting notification of I/O configuration changes
    • Using the CONFCHG macro
    • Coding a configuration change user exit routine
      • Exit routine environment
      • Programming considerations
      • Entry specifications
        • Registers at entry
        • Parameter list contents
      • Return specifications
      • Exit recovery
      • Exit routine processing
        • Example
    • Coded example: CONFCHG macro invocation of configuration change user exit
  • Detecting I/O configuration changes
  • Retrieving the current MIH time interval
  • Retrieving information about I/O hardware on an I/O path
    • Length of the CDR area
    • How IOSCDR retrieves the CDR
    • Time that IOSCDR performs I/O
  • Validating I/O paths
  • Obtaining device information for an allocation request
  • Configuring a channel path online or offline
  • Obtaining UCB information (general methods)
    • Obtaining UCB addresses for a specified device number
    • Scanning UCBs
    • Examples: Using the UCB macros
      • Example 1
      • Example 2
    • Determining if the UCB macros (general methods) are available
      • Procedure for pre-MVS/SP Version 4 libraries
      • Procedure for MVS/SP Version 4 and above libraries
  • Obtaining UCB information (limited method)
    • The UCB scan service
    • Invoking the UCB scan service
      • Input to the UCB scan service
      • Limiting the UCB scan
      • Output from the UCB scan service
      • Example: Using the UCB scan service
    • Obtaining the subchannel number for a unit control block (UCB)
  • Accessing above 16-megabyte UCBs
• Dynamic allocation
  • An allocation overview
    • Choosing the type of allocation for your program
      • Characteristics of job step allocation
      • Characteristics of dynamic allocation
    • When to avoid using dynamic allocation
    • Programming considerations for using the DYNALLOC macro
    • Selecting the type of allocation based on program requirements
  • Dynamic allocation functions
    • Using dynamic allocation functions in either a batch or interactive environment
    • Using dsname or pathname allocation
      • JCL DD statement facilities not supported by dynamic allocation
      • Dynamic allocation facilities without JCL equivalents
      • Checking for conflicts with your existing allocation environment
      • Using an existing allocation to fulfill a dsname allocation request
        • Characteristics required in your request
        • Characteristics prohibited in your request
        • Characteristics required in the existing allocation
        • System selection from multiple matching allocations
        • System creation of new ddname for existing allocation
      • Changing the parameters of an existing allocation
      • Using a new allocation to fulfill a dsname or pathname allocation request
      • Considerations when requesting dsname or pathname allocation
        • Allowing the system to generate a ddname
        • Specifying a password
        • Allocating a data set with a status of MOD
        • Allocating a dummy z/OS UNIX file
        • Determining the status of a z/OS UNIX file
        • Cataloging a data set
        • Requesting a data set that is in use
        • Retrieving information from allocation
        • Retrieving data set organization information from allocation
        • Access methods that are not available with dynamic allocation
        • Requesting an allocated but unavailable data set
        • Allocating a GDG data set
        • Retrieving volume information
        • Exceeding the control limit
    • Deallocating resources
      • Deallocating resources by dsname or pathname
      • Deallocating resources by ddname
      • Deallocating concatenated groups
      • Changing parameters at dynamic unallocation
    • Concatenating resources
      • Requesting the permanently concatenated attribute
    • Deconcatenating resources
    • Obtaining allocation environment information
    • Using dynamic allocation functions in an interactive environment
    • In-use attribute
      • Removing the in-use attribute by dsname or ddname
      • Removing the in-use attribute by task ID
    • Control limit
    • Permanently allocated attribute
    • Convertible attribute
    • Using ddname allocation
  • Installation options for DYNALLOC macro functions
    • Using default values
    • Mounting volumes and bringing devices online
    • Installation input validation routine for dynamic allocation
• Requesting dynamic allocation functions
  • Building the SVC 99 parameter list
    • Coding a dynamic allocation request
    • Obtaining storage for the parameter list
      • Estimating the amount of storage for your request
      • Characteristics of storage for parameter list
        • Clearing the storage
      • Passing the address of the obtained storage to DYNALLOC
    • Mapping storage for the parameter list
    • Setting up the request block pointer
    • Setting up the request block
      • S99RB fields
        • Length (S99RBLN)
        • Verb code (S99VERB)
        • Flags (S99FLAG1)
        • Error code (S99ERROR)
        • Info code (S99INFO)
        • Text unit pointers' address (S99TXTPP)
        • Request block extension address (S99S99X)
        • Additional flags (S99FLAG2)
        • S99RBEND
      • Relationships among selected fields
    • Setting up the text units
      • Key (S99TUKEY)
        • Number (S99TUNUM)
        • Combination (S99TUENT)
        • Length (S99TULNG)
        • Parm (S99TUPAR)
      • Structure of the text units
        • Using special characters in text units
        • Using trailing blanks in text units
        • Order of text units
        • Independence of text unit key meaning across DYNALLOC functions
    • Setting up the text unit pointer list
      • Establishing addressability to the text unit pointer list
      • Filling in the text unit pointer list
      • Setting the end of list indicator
  • Processing messages and reason codes from dynamic allocation
    • Setting up the request block extension
      • S99RBX fields
        • Request block extension identifier (S99EID)
        • Version (S99EVER)
        • Processing options (S99EOPTS)
        • Message block subpool (S99ESUBP)
        • Storage key (S99EKEY)
        • Severity level (S99EMGSV)
        • Number of message blocks returned (S99ENMSG)
        • CPPL address (S99ECPPL)
        • Not an intended programming interface (S99ERCR)
        • Not an intended programming interface (S99ERCM)
        • Message processing reason code (S99ERCO)
        • Message block freeing reason code (S99ERCF)
        • PUTLINE/WTO macro return code (S99EWRC)
        • Message block chain address (S99EMSGP)
        • Information retrieval error code (S99EERR)
        • Information retrieval information code (S99EINFO)
        • SMS reason code (S99ERSN)
    • Processing messages from dynamic allocation
      • Sending dynamic allocation messages to the end user
      • Using the functions of the IEFDB476 program
        • Extracting messages (EMRETURN)
        • Sending messages (EMPUTLIN or EMWTP)
        • Freeing or retaining message blocks (EMKEEP)
      • Linking to the IEFDB476 program
      • Providing input to IEFDB476 through EMPARMS
        • Function flags (EMFUNCT)
        • Caller identification number (EMIDNUM)
        • Number of message blocks (EMNMSGBK)
        • (EMRSV0x) - Not an intended programming interface
        • Parameter list address (EMS99RBP)
        • Parameter list address (EMDAPLP)
        • Return code (EMRETCOD)
        • CPPL address (EMCPPLP)
        • Message buffer address (EMBUFP)
        • (EMRSV0y) - Not an intended programming interface
        • Parameter address (EMWTPCDP)
        • Not an intended programming interface
      • Using EMABUFFS to receive message information from the system
        • Length of message text (EMABUFLN)
        • Offset (EMABUFOF)
        • Message text (EMABUFTX)
        • Not an intended programming interface
      • Using EMBUFS to receive message information from the system
        • Length of the first message (EMBUFL1)
        • Offset (EMBUF01)
        • First message text (EMBUFT1)
        • Not an intended programming interface
        • Length of second message (EMBUFL2)
        • Offset (EMBUF02)
        • Second message text (EMBUFT2)
      • Interpreting return codes from IEFDB476
  • Interpreting DYNALLOC return codes
    • Interpreting information reason codes from DYNALLOC
    • Interpreting error reason codes from DYNALLOC
  • SVC 99 parameter list verb codes and text units, by function
    • Coding a dsname allocation text unit
    • JCL DD statement parameters and equivalent text units
    • Using system symbols in text units
    • Dsname allocation text units
      • Ddname specification - Key = '0001'
      • Dsname specification - Key = '0002'
      • Member name specification - Key = '0003'
      • Data set status specification - Key = '0004'
      • Data set normal disposition specification - Key = '0005'
      • Data set conditional disposition specification - Key = '0006'
      • Track space type (TRK) specification - Key = '0007'
      • Cylinder space type (CYL) specification - Key = '0008'
      • Block length specification - Key = '0009'
      • Primary space quantity specification - Key = '000A'
      • Secondary space quantity specification - Key = '000B'
      • Directory block specification - Key = '000C'
      • Unused space release (RLSE) specification - Key = '000D'
      • Format of allocated space specification - Key = '000E'
      • Whole cylinder allocation (ROUND) specification - Key = '000F'
      • Volume serial specification - Key = '0010'
      • Private volume specification - Key = '0011'
      • Volume sequence number specification - Key = '0012'
      • Volume count specification - Key = '0013'
      • Volume reference to a dsname specification - Key = '0014'
      • Device description specification - Key = '0015'
      • Device count specification - Key = '0016'
      • Parallel mount specification - Key = '0017'
      • SYSOUT specification - Key = '0018'
      • SYSOUT program name specification - Key = '0019'
      • SYSOUT form number specification - Key = '001A'
      • SYSOUT output limit specification - Key = '001B'
      • Unallocation at CLOSE specification - Key = '001C'
      • SYSOUT copies specification - Key = '001D'
      • Label type specification - Key = '001E'
      • Data set sequence number specification - Key = '001F'
      • Password protection specification - Key = '0020'
      • Input only or output only specification - Key = '0021'
      • Expiration date specification (short form) - Key = '0022'
      • Retention period specification - Key = '0023'
      • Dummy data set specification - Key = '0024'
      • Forms control buffer (FCB) image identification specification - Key = '0025'
      • Form alignment and image verification specification - Key = '0026'
      • QNAME specification - Key = '0027'
      • Terminal specification - Key = '0028'
      • Universal character set (UCS) specification - Key = '0029'
      • Fold mode specification - Key = '002A'
      • Character set image verification specification - Key = '002B'
      • DCB reference to a dsname specification - Key = '002C'
      • DCB reference to a ddname specification - Key = '002D'
      • SYSOUT remote work station specification - Key = '0058'
      • SYSOUT hold queue specification - Key = '0059'
      • Subsystem name request specification - Key = '005F'
      • Subsystem parameter specification - Key = '0060'
      • PROTECT specification - Key = '0061'
      • SYSOUT user ID specification - Key = '0063'
      • Burst specification - Key = '0064'
      • Character arrangement table specification - Key = '0065'
      • Copy groups specification - Key = '0066'
      • Flash forms overlay specification - Key = '0067'
      • Flash forms overlay count specification - Key = '0068'
      • Copy modification module specification - Key = '0069'
      • Copy module table reference specification - Key = '006A'
      • DEFER specification - Key = '006C'
      • EXPIRATION DATE specification (long form) - Key = '006D'
      • Override job affinity - Key = '0070'
      • CTOKEN return specification - Key = '0071'
      • SMSHONOR specification – Key = '0076'
      • Access specification - Key = '8001'
      • OUTPUT statement reference - Key = '8002'
      • CNTL specification - Key = '8003'
      • Storage class specification - Key = '8004'
      • Management class specification - Key = '8005'
      • Data class specification - Key = '8006'
      • Record organization specification - Key = '800B'
      • Key offset specification - Key = '800C'
      • Copy DD specification - Key = '800D'
      • Copy profile specification - Key = '800E'
      • Copy model specification - Key = '800F'
      • Average record specification - Key = '8010'
      • Data set type specification - Key = '8012'
      • Spin data set specification - Key = '8013'
      • Segment spin data set specification - Key = '8014'
      • z/OS UNIX file path specification - Key = '8017'
      • z/OS UNIX file options - Key = '8018'
      • z/OS UNIX file access attributes - Key = '8019'
      • z/OS UNIX file normal disposition specification - Key = '801A'
      • z/OS UNIX file abnormal disposition specification - Key = '801B'
      • Record-level sharing specification - Key = '801C'
      • Organization of a z/OS UNIX file - Key = '801D'
      • VSAM RLS log stream specification - Key = '801F'
      • CCSID specification - Key = '8020'
      • Block size limit specification - Key = '8022'
      • Key label 1 specification - Key = '8023'
      • Key label 2 specification - Key = '8024'
      • Key encode 1 specification - Key = '8025'
      • Key encode 2 specification - Key = '8026'
      • Extended attributes specification - Key = '8028'
      • FREEVOL specification - Key = '8029'
      • SPIN interval for the allocated SYSOUT data set - Key = '802A'
      • SYMLIST on a DD statement - Key = '802B'
      • DSNTYPE version - Key = '802C'
      • Maximum PDSE Generation - Key = '802D'
      • GDGORDER specification – Key = '802E'
    • JCL DD statement DCB subparameters and equivalent text units
    • DCB attribute text units
      • BFALN specification - Key = '002E'
      • BFTEK specification - Key = '002F'
      • BLKSIZE specification - Key = '0030'
      • BUFIN specification - Key = '0031'
      • BUFL specification - Key = '0032'
      • BUFMAX specification - Key = '0033'
      • BUFNO specification - Key = '0034'
      • BUFFOFF specification - Key = '0035'
      • BUFOUT specification - Key = '0036'
      • BUFRQ specification - Key = '0037'
      • BUFSZ specification - Key = '0038'
      • CODE specification - Key = '0039'
      • CPRI specification - Key = '003A'
      • DEN specification - Key = '003B'
      • DSORG specifications - Key = '003C'
      • EROPT specification - Key = '003D'
      • GNCP specification - Key = '003E'
      • INTVL specification - Key = '003F'
      • KEYLEN specification - Key = '0040'
      • LIMCT specification - Key = '0041'
      • LRECL specification - Key = '0042'
      • MODE specification - Key = '0043'
      • NCP specification - Key = '0044'
      • OPTCD specification - Key = '0045'
      • Receiving PCI specification - Key = '0046'
      • Sending PCI specification - Key = '0047'
      • PRTSP specification - Key = '0048'
      • RECFM specification - Key = '0049'
      • First buffer reserve specification - Key = '004A'
      • Secondary buffer reserve specification - Key = '004B'
      • SOWA specification - Key = '004C'
      • STACK specification - Key = '004D'
      • THRESH specification - Key = '004E'
      • TRTCH specification – Key = '004F'
      • Diagnostic trace specification (DIAGNS=TRACE) - Key = '0054'
      • FUNC= specification - Key = '005A'
      • FRID= specification - Key = '005B'
      • Record length specification - Key = '006B'
      • Kilobyte BLKSIZE type specification - Key = '0072'
      • Megabyte BLKSIZE type specification - Key = '0073'
      • Gigabyte BLKSIZE type specification - Key = '0074'
    • Non-JCL dynamic allocation functions
      • Password specification - Key = '0050'
      • Permanently allocated attribute specification - Key = '0052'
      • Convertible attribute specification - Key = '0053'
      • Ddname return specification - Key = '0055'
      • Dsname return specification - Key = '0056'
      • DSORG return specification - Key = '0057'
      • Subsystem request specification - key = '005C'
      • Volume serial return specification - Key = '005D'
      • Subsystem request type specification - Key = '0062'
      • Spool data set browse token specification - Key = '006E'
      • Volume interchange specification - Key = '006F'
      • Subsystem request specification - Key = '0075'
      • Uniquely allocated temporary data set - Key = '0077'
    • Dynamic unallocation text units
      • Ddname specification - Key = '0001'
      • Dsname specification - Key = '0002'
      • Member name specification - Key = '0003'
      • Overriding disposition specification - Key = '0005'
      • Unallocate option specification - Key = '0007'
      • Remove in-use option specification - Key = '0008'
      • Overriding SYSOUT nohold specification - Key = '000A'
      • Overriding SYSOUT class specification - Key = '0018'
      • Overriding SYSOUT remote workstation specification - Key = '0058'
      • Overriding SYSOUT hold queue specification - Key = '0059'
      • Overriding SYSOUT user ID specification - Key = '0063'
      • Overriding spin data set specification - Key = '8013'
      • z/OS UNIX file path specification - Key = '8017'
      • z/OS UNIX overriding file disposition specification - Key = '801A'
    • Dynamic concatenation text units
      • Ddname specification - Key = '0001'
      • Permanently concatenated attribute specification - Key = '0004'
    • Dynamic deconcatenation text unit
      • Ddname specification - Key = '0001'
    • Text units for removing the in-use attribute based on task ID
      • TCB address specification - Key = '0001'
      • Current task option specification - Key = '0002'
    • Ddname allocation text units
      • Ddname specification - Key = '0001'
      • Return DUMMY indication specification - Key = '0002'
    • Dynamic information retrieval text units
      • Ddname specification - Key = '0001'
      • Dsname specification - Key = '0002'
      • Return ddname specification - Key = '0004'
      • Return dsname specification - Key = '0005'
      • Return member name specification - Key = '0006'
      • Return status specification - Key = '0007'
      • Return normal disposition specification - Key = '0008'
      • Return conditional disposition specification - Key = '0009'
      • Return data set organization specification key = '000A'
      • Return limit specification - Key = '000B'
      • Return dynamic allocation attribute specification - Key = '000C'
      • Return last entry specification - Key = '000D'
      • Return data set type specification - Key = '000E'
      • Relative request number specification - Key = '000F'
      • Return first volume serial specification - Key = '0010'
      • Return ddname extended specification - Key = '0011'
      • Return relative position specification - Key = '0012'
      • z/OS UNIX file path specification - Key = '8017'
      • CNTL specification - Key = 'C003'
      • Return storage class specification - Key = 'C004'
      • Return management class specification - Key = 'C005'
      • Return data class specification - Key = 'C006'
      • Return record organization specification - Key = 'C00B'
      • Return key offset specification - Key = 'C00C'
      • Return copy DD specification - Key = 'C00D'
      • Return copy profile specification - Key = 'C00E'
      • Return copy model specification - Key = 'C00F'
      • Return average record specification - Key = 'C010'
      • Return data set type specification - Key = 'C012'
      • Return spin data set specification - Key = 'C013'
      • Return segment spin data set specification - Key = 'C014'
      • Return z/OS UNIX file path specification - Key = 'C017'
      • Return z/OS UNIX file options - Key = 'C018'
      • Return z/OS UNIX file access attributes - Key = 'C019'
      • Return z/OS UNIX file normal disposition specification - Key = 'C01A'
      • Return z/OS UNIX file abnormal disposition specification - Key = 'C01B'
      • Return organization of a z/OS UNIX file - Key = 'C01D'
      • Return spin of interval specification - Key = 'C02A'
      • Return symbol list on a DD statement - Key = 'C02B'
      • Return DSNTYPE version information - Key = 'C02C'
      • Return MAXGENS generation information - Key = 'C02D'
      • Return GDGORDER specification – Key = 'C02E'
  • Example of a Dynamic Allocation Request
• Dynamic output
  • Creating and naming output descriptors
    • System generated names
    • Job step considerations
    • Output descriptors and text units
      • Table of dynamic output text units and JCL equivalents
      • Relationship between text units and JCL equivalents
        • OUTPUT JCL statement
        • Text units
    • Deleting output descriptors
    • Specifying SYSOUT without an output descriptor
    • Dynamic output programming example
      • Dynamic output programming example (continued)
      • Dynamic output programming example (continued)
      • Dynamic output programming example (concluded)
• Scheduler JCL facility (SJF)
  • Understanding SJF terms
    • The SJF environment
    • Retrieving output descriptor information (SJFREQ macro with RETRIEVE)
      • Initializing the keyword list
      • Establishing a storage area
      • Information returned from SJF RETRIEVE processing
    • Merging SWBTUs (SJFREQ macro with SWBTU_MERGE)
    • Validating and building text units (SJFREQ macro with VERIFY)
    • SJFREQ VERIFY functions
    • Preparing to use VERIFY for validating and building text units
    • Examples of using SJFREQ VERIFY functions
      • Validate a statement name
      • Validate a keyword operand
      • Validate and build a text unit for a keyword operand and subparameters
      • Validate and build a text unit for a keyword operand with a sublist
      • Requesting last call
    • Freeing the SJF environment (SJFREQ macro with TERMINATE)
  • Understanding the OUTDES statement
    • Operand and keyword operand abbreviations
    • Comments and line continuation
    • Delimiters
    • Rules for parsing data with and without quotation marks
    • OUTDES statement syntax
• Processing user trace entries in the system trace table
  • Formatting a USRn trace table entry
  • Replacing a USRn TTE formatting routine
    • Parameters passed to the USRn formatter
    • Return codes from the USRn formatter
    • Printing the trace output buffer contents
    • Handling errors during TTE formatting
• Using system logger services
  • What is system logger?
    • The log stream
      • Coupling facility log stream
      • DASD-only log stream
  • The system logger configuration
    • The system logger component
  • Overview of authorized system logger services
    • Summary of system logger services
    • Coding a system logger complete exit for IXGBRWSE, IXGWRITE, and IXGDELET
      • Information passed to the complete exit
      • Environment
      • Input specifications
        • Registers at entry
        • Return specification
      • Programming considerations
    • Using ENF event code 48 in system logger applications
  • IXGCONN: Connecting to and disconnecting from a log stream
    • Connecting as a resource manager
      • Using ENF event code 48 with a resource manager
    • Using ENF event 48 when a connect request is rejected
    • Coding a resource manager exit for IXGCONN
      • Information passed to the resource manager exit
      • Environment
      • Input specifications
      • Registers at entry
      • Return specification
      • Programming considerations
      • Overriding delete requests
      • When the resource manager exit hangs
  • IXGDELET: Deleting log blocks from a log stream
    • Delete requests and resource manager exit processing
  • Setting up the system logger configuration
    • Writing an ENF event 48 listen exit
  • Logger server address space availability considerations
    • ENF 48 and system logger initialization
    • ENF 48 event code scenarios
    • Considerations for logger resources temporarily unavailable
    • Considerations for logger log stream disconnected
  • When things go wrong: Recovery scenarios for system logger
    • When a resource manager fails
• System REXX
  • Planning to use system REXX
  • Security
  • Argument and variable processing
  • Input/output files
  • Functions
  • Time limits and canceling a request
  • Error handling
  • Examples
• z/OS FBA services
  • z/OS Distributed Data Backup (zDDB)
  • z/OS FBA devices
    • Controlling access to z/OS FBA devices
  • z/OS FBA services
    • Querying and allocating FBA devices
    • Reading from and writing to z/OS FBA devices
    • Erasing data on z/OS FBA devices
    • Unallocating z/OS FBA devices
    • Improving performance when using IOSFBA services
    • Providing a recovery or resource manager
• Using the unit verification service
  • Functions
    • Check groups - Function code 0
    • Check units - Function code 1
    • Return unit name - Function code 2
    • Return unit control block (UCB) addresses - Function code 3
    • Return group ID - Function code 4
    • Indicate unit name is a look-up value - Function code 5
    • Return look-up value - Function code 6
    • Convert device type to look-up value - Function code 7
    • Return attributes - Function code 8
    • Check units with no validity bit - Function code 9
    • Specify subpool for returned storage - Function code 10
    • Return unit names for a device class - Function code 11
    • Callers of IEFEB4UV
    • Callers of IEFGB4UV or IEFAB4UV
      • Input to and output from unit verification service routines
      • Input parameter list
      • Input and output data structures
      • Register 15 if request fails
      • Requesting function code 0 (check groups)
        • Input
        • Output
      • Requesting function code 1 (check units)
        • Input
        • Output
      • Requesting function code 2 (return unit name)
        • Input
        • Output
      • Requesting function code 3 (return UCB addresses)
        • Input
        • Output
      • Requesting function code 4 (return group ID)
        • Input
        • Output
      • Requesting function code 5 (indicate unit name is a look-up value)
        • Input
        • Output
      • Requesting function code 6 (return look-up value)
        • Input
        • Output
      • Requesting function code 7 (convert device type to look-up value)
        • Input
        • Output
      • Requesting function code 8 (return attributes)
        • Input
        • Output
      • Requesting function code 9 (check units with no validity bit)
        • Input
        • Output
      • Requesting function code 10 (specify subpool for returned storage)
        • Input
        • Output
      • Requesting function code 11 (return unit names for a device class)
        • Input
        • Output
      • Requesting multiple functions - Examples
      • Example 1 - Function codes 0 and 1
        • Input
        • Output
      • Example 2 - Function codes 3 and 10
        • Input
        • Output
      • Example 3 - Function codes 1 and 5
        • Input
        • Output