SPoD-Specific Limitations and Considerations

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# SPoD-Specific Limitations and Considerations

When you are working with Natural Single Point of Development, you will encounter a few limitations which are due to the different capabilities of the graphical user interface available on the local site and the character-based user interface that exists on the remote site. In addition, this document includes hints which are important for the efficient use of the remote development facilities.

This document covers the following topics:

- Limitations

- Performance Considerations

- Natural Documentation and Online Help

#### Editor Features With SPoD

You can use Natural's Single Point of Development with different versions of Natural on a variety of platforms. Depending on the server environment you are using together with Natural for Windows (client), the editors offer different features. For further information, refer to the section Editor Features With SPoD in the Natural for Windows Editors documentation.

## Limitations

The following topics are covered:

- Back-End Program

- System Commands

- Profile Parameters

- Terminal Commands

- Moving/Copying Error Messages

- LIST DDM, EDIT DDM

- Maps Containing GUI Elements

- Field Sensitive Maps

- Resources

- Dialogs

- Natural ISPF Macros and Recordings

- SYSLIB/SYSLIBS

- Allow Lower Case Input in Program Editor of Natural Studio

- Terminal Emulation

- Dependencies between XRef Evaluation and Predict

- Remote Debugging

### Back-End Program

If a back-end program has been specified (for example, by means of the Natural profile parameter `PROGRAM`), it is not invoked if the Natural session is executing on a Natural Development Server.

### System Commands

The following topics are covered:

- System Command SYSDDM
- System Commands Unavailable for Remote Development
- System Commands Entered Directly on the Development Server

#### System Command SYSDDM

The system command `SYSDDM` is not available, since the DDMs are listed in the tree view under the node DDM, and because all functions of the utility `SYSDDM` are available by using Natural Studio's context menu or menu bar.

#### System Commands Unavailable for Remote Development

The following system commands are not available, since their use would make no sense with a graphical user interface:

- `EDT`

- `HELLO`

- `MAINMENU`

#### System Commands Entered Directly on the Development Server

All system commands which are not entered in the user interface of Natural Studio are executed directly by the Development Server without control of Natural Studio. As a result, the character-based representation of the corresponding command appears in the terminal emulation window. This is the case when the `STACK TOP COMMAND` mechanism is used or when a system command is directly entered inside the terminal emulation window.

During the mapping phase any `STACK` commands entered in the text box Session Parameters are processed within Natural Studio and the corresponding Natural Studio windows are used.

It is even possible to invoke the mainframe editors. However, this may lead to inconsistencies (see also Object Locking in the Natural for Windows documentation). Therefore, you are strongly recommended to use only Natural Studio's GUI editors.

The commands `HELLO` and `MAINMENU` do not cause a screen output on the development server side, since this would not make any sense in the SPoD environment. Instead of the menu-driven user interface, the dialogs provided in Natural Studio are used.

### Profile Parameters

#### CP Parameter

The Natural profile parameter setting `CP=AUTO` is not supported in a SPoD environment. (`AUTO` means that the code page name from the user terminal is taken, if available.)

### Terminal Commands

Using terminal commands in a SPoD environment is only possible within the terminal emulation window. Entering terminal commands in the command line of Natural Studio is not possible.

### Moving/Copying Error Messages

Moving and copying of error messages is different in remote and local environments:

- When error messages are moved or copied within the remote environment or are moved or copied from the local to the remote environment or vice versa: the error messages involved are merged, that is,

  - error messages which already exist in the target environment are replaced,

  - messages which do not exist in the source library are kept in the target library,

  - messages which do not exist in the target library are added.

- When error messages are moved or copied within the local environment, the messages involved are handled on file level, that is,

  - all error messages (that is, files) of a language are deleted and

  - the file from the source library is created anew in the target library.

### LIST DDM, EDIT DDM

In contrast with a pure Natural mainframe environment, that is, without remote development from Natural Studio, the command `EDIT DDM` is available also from a user library. This means that it is not necessary to expand the DDM node in the tree view to be able to edit a specific DDM. However, when Natural Security is used, the use of the commands `LIST DDM` and `EDIT DDM` can be restricted only via the security profile of the mainframe Natural utility `SYSDDM`.

### Maps Containing GUI Elements

Maps containing GUI elements can be moved or copied from the local environment to a remote environment. However, the GUI elements are not displayed when the map is being tested or executed on the remote environment.

### Field Sensitive Maps

For these maps, the consistency check for a map field is made as soon as the user input has been entered. Field sensitive maps can be moved or copied from the local environment to a remote environment. However, a field sensitive map cannot be tested or executed on a remote mainframe environment.

### Resources

On the mainframe, objects of type resource can be handled (displayed, copied, deleted, etc.). See Using Non-Natural Files - Resources in the Natural Programming Guide.

By default, resouces are not handled by Natural Development Server for performance reasons; that is, resources are normally not displayed.

If you want Natural Development Server to handle resources, use the user exit `NDV-UX03` (source: `NDV-SX03`), which allows you to enable/disable the display of resources in Natural Studio for all or certain users only.

The server behaves in the following way: If the user exit exists and the flag `DISPLAY-RESOURCES` contained therein is set (`Y`), the server checks in the Library Statistical Record whether the number of resources is greater than 0. If so, the library is searched also for resources.

### Dialogs

Dialogs can be stored on the mainframe. Therefore it is possible to move or copy dialogs from the local environment to a remote environment. Private resource files of a dialog will not be moved or copied together with the dialog. It is also possible to list dialogs in a remote environment. New dialogs cannot be created and dialogs cannot be edited in a remote environment.

### Natural ISPF Macros and Recordings

As the object types Natural ISPF Macro and Recording available with Natural for Mainframes cannot be processed by Natural Studio, they will not be displayed in the tree view of the library work space. If a library consists only of such object types, the library will be displayed nevertheless in the tree view, but without any subnodes.

If a library containing such object types is deleted, then the objects of these two specific object types will not be deleted and the library will continue to be displayed in the tree view.

Objects of the types Natural ISPF Macro and Natural ISPF Recording cannot be linked to an application.

### SYSLIB/SYSLIBS

The restricted libraries `SYSLIB`/`SYSLIBS` of the server are not shown in Natural Studio's tree view, because a logon to these libraries is not possible. These libraries can be modified only by using a Natural utility such as `SYSMAIN` or the Object Handler.

### Allow Lower Case Input in Program Editor of Natural Studio

Natural Studio's program editor is case-sensitive, that is, lower case input will be included in the program source in lower case. The compiler on the Natural Development Server, however, expects upper case code in its normal setting. This issue can be fixed by setting the compiler option `LOWSRCE=ON`. But this setting will have specific side effects which should be noticed. Refer to the `CMPO` profile parameter in the Natural Parameter Reference.

### Terminal Emulation

The terminal emulation supports 3270 Model 2 screens. The support of 3270 Model 3, 4 and 5 screens is planned for one of the next versions of Natural Single Point of Development.

### Dependencies between XRef Evaluation and Predict

If you are using dynamic language assigned when calling other objects such as `INPUT USING MAP 'MAP1&'`, the connection between caller and called object cannot be retrieved by using XRef Evaluation.

Natural on the mainframe supports case-sensitive calls to other objects such as `PERFORM SUBROUTINE`. With the current version of SPoD, this may lead to strange results when, in XRef Evaluation, trees are expanded and it is not possible to request case-sensitive calls with the filter dialog.

### Remote Debugging

When the remote debugging facility was implemented, the goal was not to provide any new functions, but to support the existing essential debugging functions under the Natural Development Server. These functions are:

- Stepmode

- Breakpoints

- Watchpoints

- Display and modification of variables and their contents during a break.

Generally, it was intended to provide for compatibility between the debug functionality that exists in a Natural on mainframes and a Natural on PC. Hence, the current state of development constitutes the lowest possible common denominator. Especially the debug statistics as supported on mainframes are not yet supported in a remote debug environment.

#### Which Differences Exist in Debugging in a Mainframe Environment and in Natural Studio?

The following tables provide an overview of differences that exist between Natural debugging in a mainframe environment and debugging in Natural Studio.

Explanation of the table headings:

MF | Describes debugging functionality available or not available in a mainframe Natural environment.
SPoD | Describes debugging functionality available or not available in a Natural Single Point of Development environment using Natural Studio as a development client and a mainframe Natural Development Server.
PC | Describes debugging functionality available or not available in Natural Studio (stand alone).

- Restarting a Debug Process

  MF | The restart function is not supported.
  SPoD | The restart function is not supported.
  PC | Debug on PC offers a special restart function which is not available for remote debugging on mainframe.

- EXIT from Debugger

  MF | System command `RUN`: leave the Natural Debugger. The program execution continues.
  System command `STOP`: both debugging and execution are terminated.
  SPoD | Stop command in Debug menu: debug mode terminates, program execution stops.
  PC | Stop command in Debug menu: debug mode terminates, program execution stops.

- STEP OVER

  MF | Syntax of `STEP SKIPSUBLEVEL` is used instead of `STEP OVER`.
  SPoD | `STEP OVER` is applicable for called objects on a different level (`CALLNAT`, etc). It is not applicable for internal subroutines.
  PC | `STEP OVER` is supported for any called objects and, in addition, for internal subroutines.

- Set Next Statement (Natural Studio Context Menu Command)

  MF | Not applicable.
  SPoD | Not supported.
  PC | Supported. Allows you to continue the execution at a chosen line.

- System Variables: Display/Modify

  MF | System variables can be displayed, but cannot be modified.
  SPoD | System variables can be displayed, but cannot be modified.
  PC | System variables can be displayed and modified.

- Display of Binary Variables

  MF | Either alphanumeric or hexadecimal display of binary variables can be selected. In alphanumeric display, binary variables with lengths ranging from 1 to 4 are interpreted and displayed as numerical values. Binary variables with lengths > 4 are displayed in alphanumeric representation.
  SPoD | Binary variables are always represented as hexadecimal values.
  PC | Binary variables are always represented as hexadecimal values.

- Modify Dynamic Variables

  MF | During the debug process, the content of a dynamic variable can be modified in the given length. Modification of length of dynamic variable during debug is not supported.
  SPoD | Content of dynamic variable can be modified in given length.
  PC | Both content and length of dynamic variable can be modified during the debug process.

- Maximum Length when Displaying Variable Values

  MF | Displays full content of variable; long variables are displayed in chunks of maximally 256 bytes. If Unicode is used: max. 256 bytes = 128 characters.
  SPoD | Displays maximally 253 bytes. If Unicode is used: max. 252 bytes = 126 characters.
  PC | Displays maximally 253 characters.

- Maximum Length of Watchpoint Variables

  MF | Maximally 253 bytes. If Unicode is used: max. 252 bytes = 126 characters.
  SPoD | Maximally 253 bytes. If Unicode is used: max. 252 bytes = 126 characters.
  PC | Maximally 253 characters.

- Watchpoint: Display of Break Line

  MF | After the watchpoint has been registered, the Debugger marks the preceding (already executed) statement.
  SPoD | After the watchpoint has been registered, the Debugger stops at the current position in the program. This is the statement to be executed next.
  PC | After the watchpoint has been registered, the Debugger stops at the current position in the program. This is the statement to be executed next.

- Several Watchpoint Breaks per Line of Program

  MF | Multiple breaks on the same line may arise for the same watchpoint variable (because of different watchpoint operators). The hit counter is incremented accordingly.
  SPoD | Multiple breaks on the same line may arise for the same watchpoint variable (because of different watchpoint operators). The hit counter is incremented accordingly.
  PC | Several watchpoint definitions for the same variable result in a maximum of one break per line, hit counts of all watchpoint definitions are incremented.

- Breakpoint Definition

  MF | Breakpoints can only be defined for programs which are found in the current library or in any steplib.
  SPoD | Breakpoints can only be defined for programs which are found in the current library or in any steplib.
  PC | Breakpoints for programs can be defined in any library (not necessarily in the current library or steplib).

- Breakpoints BEG and END

  MF | The symbolic breakpoints `BEG` and `END` (first and last executed statement) are supported.
  SPoD | Breakpoints `BP-BEG` and `BP-END` are not supported.
  PC | Breakpoints `BP-BEG` and `BP-END` are not supported.

- Debugging of Programs which are Called through the Stack

  MF | Stacked programs can be debugged when any breakpoint or watchpoint has been defined, but they cannot be entered automatically in step mode.
  SPoD | Programs on stack can be entered in step mode.
  PC | Programs on stack can be entered in step mode.

- Edit/Stow a Program during Debug

  MF | A NAT0932 (program version) error appears if during the debug process the debugged program was stowed and loaded into the buffer pool.
  SPoD | A NAT0932 (program version) error appears if during the debug process the debugged program was stowed and loaded into the buffer pool.
  PC | Change and stow of program during debug is possible.

- Call Stack

  MF | The debug command `OBJCHAIN` displays a list of active programs and their levels.
  SPoD | The current program and its level are displayed in the call stack window.
  PC | All active programs and their levels are displayed in the call stack window.

## Performance Considerations

### Progress Information

The working situation displayed in the library workspace of Natural Studio is based on the representation of the entire user system files.

The tree view window opens when the user connects to the Natural Development Server. For this, the entire system file has to be analyzed and the corresponding information has to be transferred from the Natural Development Server to the Natural Studio client. In the case of very large system files, the build-up of the tree view window can be very time consuming. Status information displayed in the status bar keeps the user informed about the progress of the screen build-up operation. This is to avoid the impression that the connection to the Natural Development Server might be interrupted.

Tip
Switch on the status bar using the View > Status Bar function of the menu bar. Make sure that the transfer rate of your network is 100 Mbit/s at minimum.

### Filter Definition

Another possibility to reduce the amount of data read while mapping the environment is to supply filter definitions on system file or library level.

Tip
In the context menu of a system file and library node it is possible to apply filter definitions. Using these definitions on the client side, you can limit the number of libraries/objects displayed in the tree view.

### Refresh Options

In the default configuration of Natural Studio, all operations which result in a modification of the system file, for example, moving or copying objects, but also a `SAVE` or `STOW` command, will cause the tree view window contents to be refreshed, which can be a very time consuming process in the case of very large system files.

Tip
By default, the Refresh function is set to Full automatic refresh. Change the automatic refresh function by choosing Optimized automatic refresh or No automatic refresh in the context menu.

Since the tree view of the application workspace displays only the objects that are linked to the application, the build-up of its tree view screen is consequently considerably faster, which is another advantage of using the application workspace.

### Object Lists on Mainframes

In mainframe environments, libraries may contain a huge number of objects. Expanding such a library in a tree node in the NaturalONE Server view or in the Natural Studio views can take a long time.

Tip
Install the hyperdescriptor as described in NaturalONE in a Nutshell > Performance Aspects in the NaturalONE documentation. The hyperdescriptor is also used by Natural Studio. It can significantly improve the database access required for reading object names the Natural system file.

### Library Statistical Record

In a Natural Single Point of Development environment, either local Natural libraries are accessed or Natural Studio requests the library statistical data from the remote development server. In the local environment, the data are stored persistently in the FILEDIR structure of the library. In the case of a mainframe development server, Natural objects are stored in system files in the database and the requested statistical data of a library are not stored permanently.

In order to reduce the number of Adabas calls and to improve the performance, a statistical record has been introduced.

The program `NDVCSTAR` is provided to initialize a complete system file, a range of libraries or a single library on a system file with the Library Statistical Records, see Initialization of Library Statistical Records.

The following topics are covered below:

- Concept
- Data Consistency
- Restrictions
- Initialization of Library Statistical Records

#### Concept

In a Natural Single Point of Development environment, a library statistical record is created and maintained for every library of the `FUSER` or `FNAT` system file. This statistical record resides on the same system file where the library resides and contains the following information for every library:

- Total number of objects

- Total number of all sources

- Total number of all cataloged objects

- Total number of objects for every object type

- Accumulated size of all sources

- Accumulated size of all cataloged objects

- Accumulated size of sources for every object type

- Accumulated size of all cataloged objects for every object type

Supported object types:

- Program

- Map

- GDA

- LDA

- PDA

- Subroutine

- Helproutine

- Subprogram

- Copycode (source only)

- Text (source only)

- Command Processor

- Dialog (source only)

- Class

- Error Message (source only)

- Function

- Adapter

- Resource

When Natural Studio requests the statistics for a library the first time, the library statistical record is created and saved in the appropriate system file. Once the library statistical record has been built, all requests from Natural Studio will be satisfied by reading and sending the contents of the statistical record instead of rebuilding the complete library statistics.

When the user initiates an explicit refresh for a library, the statistical record is rebuilt completely.

#### Data Consistency

The library statistical record of a mainframe development server is supported only in a Single Point of Development environment. The statistical record is always up to date if all system file modifications are initiated in this environment.

All commands or operations triggered by Natural Studio which will modify the system files (add new object or copy, move, delete, rename object, etc.) will update the library statistical record on the development server.

In addition, the library statistical record is regenerated if an object list for the whole library is requested or the statistical record for a given object type is updated if an object list for this type is requested.

To ensure consistency of the data in the library statistical records of your `FNAT` and `FUSER` system files, you are strongly recommended to make changes on the same `FNAT` and `FUSER` system file used in a Single Point of Development environment exclusively in that environment.

| Warning: When working with Natural Studio, care must be taken to start all commands or utilities from within Natural Studio. It is not admissible to issue system commands in the terminal emulation window, for example, at a `MORE` prompt or in a command line. In such a case, the library statistical data might become inconsistent. The same is true if you start a server application that directly changes the `FNAT` or `FUSER` system file.

Such inconsistencies may be resolved after the next regeneration (implicit rebuild via get object list or explicit refresh) of the library statistical record is forced.

#### Restrictions

Statistical records cannot be used for read-only system files. In this case, the old behavior is used.

#### Initialization of Library Statistical Records

In order to initialize the Library Statistical Records of a a complete system file, a range of libraries or a single library on a system file you can invoke the program `NDVCSTAR`.

The following options are provided:

Option | Meaning | Default value
--- | --- | ---
`Library name range` | Possible values: | `*`
blank or `*` (asterisk) | All libraries.
`value`> | All libraries with names greater than or equal to `value`.
`value`< | All libraries with names less than or equal to value.
`DBID, FNR` | The database ID (DBID) and file number (FNR) of the system file where the Natural libraries are stored. If no values (or `0`) are specified, the current `FUSER` or `FNAT` system file is used. | `0,0`
`Password, Cipher` | The password and cipher code of the Adabas file where the Natural libraries are stored. | None
`Update existing records` | Specifies whether existing Library Statistical Records are to be processed. Possible values: | `N`
`Y` (yes) | Regenerate existing Library Statistical Records.
`N` (no) | Skip existing Library Statistical Records.
`Display library names` | Specifies whether a processing message of the library currently processed is to be displayed. Possible values: | `1`
`Y` (yes) | Display processing messages.
`N` (no) | Display only error messages.

To invoke the program NDVCSTAR

- At a `NEXT`/`MORE` prompt or in a Natural command line, enter `NDVCSTAR` and press ENTER.

To execute the program NDVCSTAR in batch mode

- Enter `NDVCSTAR` followed by the desired options.

  Examples:

      NDVCSTAR *,1,47,,,N,Y

  On the system file with `DB=D=1`, `FNR=47`, this command creates, for all libraries that do not yet have a Library Statistical Record, a new one. Any existing library statistical records are skipped. For every library found, a processing message is displayed.

      NDVCSTAR ABC*,,,,,Y,Y

  This command creates or regenerates the library statistical record on the current `FUSER` system file for all libraries that start with `ABC`. For every library found, a processing message is displayed.

## Natural Documentation and Online Help

The following restrictions apply to the Natural documentation and the Windows-based online help when you are using a Natural Development Server (NDV) for remote development:

- The online help currently available with Natural Studio contains only the Natural for Windows documentation and the SPoD client documentation.

- Therefore this online help may describe Natural features which are not or not yet supported on the mainframe platform.

- Natural features that are available only on mainframes are missing.

- Particularly in the sections dealing with the Natural programming language, minor but important differences due to hardware platforms, operating systems, TP monitors, etc. may exist.

We ask you to refer to the Natural for Mainframes documentation set for full details.

### On this page

- Limitations
- Performance Considerations
- Natural Documentation and Online Help