Non-IBM i target restrictions and considerations for DDM

Whether they apply depends on what the target system supports. You should refer to that system's documentation for more information.

• Only field data types that are common to the source and server systems can normally be processed by HLL applications. Floating-point data is an example of a data type that might not be common. Records can be transmitted that contain floating-point data, but the representation of floating-point data sent between systems might differ.

  The packed signs sent between systems might differ; for example, one system might use a C and another system might use an F.

  Note: It is possible for you to write your application program so that it interprets the byte string for a record processed through a DDM file in any way that you want. However, whenever you do this, it is your responsibility to ensure that the data is handled correctly.
• Any operations that request a delay period before returning, such as for record lock wait times, might be rejected or changed to a zero wait time by the server system.
• Lock requests can be changed by the server system to a more restrictive lock. This might prevent some operations from occurring at the same time that can otherwise be performed on the local IBM i operating system. See Allocate Object (ALCOBJ) command for more information.
• Some IBM i parameters are ignored or cause errors if they are used during remote file processing on server systems that do not run IBM i. Examples are the FRCRATIO and FMTSLR parameters on some of the file commands. For more information, see OVRDBF (Override with Database File) command and see Copy commands with DDM.
• Member names are not supported in the DDM architecture. When the server system is not running IBM i or System/38, CL commands that have a MBR parameter, such as the Clear Physical File Member (CLRPFM) command, must be changed if the parameter specifies a member name that is different than the file name. If the member name is different, an error occurs if the command is used for a remote file that does not reside on the IBM i operating system. For some commands, MBR(*FIRST) or MBR(*LAST) is also valid. See Member-related commands with DDM for a list of all the CL commands related to file members, and for those that are not valid for accessing files on server systems that do not run IBM i.
  Note: MBR(*LAST) is not supported by System/38.
• If a parameter on a CL command requires the name of a source file, then the names of the DDM files that refer to target files that are not on an IBM i operating system cannot be specified. The IBM i operating system cannot determine whether a remote file on a target that does not reside on IBM i is in fact a source file. (See Source file commands for a list of all the CL commands related to source files.)
• Certain IBM i commands that are valid for IBM i or System/38 server systems are not valid for other targets. See DDM-related CL command lists for the lists of commands that are not supported when the target is not an IBM i or a System/38.