Personal computer client to IBM i server considerations for DDM

IBM i Access Family uses Level 3.0 of the DDM architecture stream file access support to access folder management services (FMS) folders and documents. The following considerations apply to IBM i Access Family use of the IBM i DDM target support for the DDM architecture, Level 3.0. Other client systems that send Level 2.0 or Level 3.0 DDM architecture requests for stream files and directories might be able to use this information to help in connecting to the IBM i operating system by using DDM.

• A FMS must follow the file or directory name to access folder management services (FMS) folders and documents. There can be one or more blanks between the end of the name and the FMS.
• A leading slash (/) signifies the name is fully qualified. If there is no leading slash, any current directory in use is added to the front of the name given.
• The total length of a fully qualified document name is 76 characters. This includes any current directory that may be in use. This does not include the trailing FMS, which is used for typing purposes.
• A / FMS signifies the root folder for a directory name.
• To reduce the number of messages logged to the job log, some errors occurring on the IBM i target during open, get, put, and close document operations are not logged to the job log. See Table 1 for an illustration of these return codes.

  Table 1. IBM i return codes

  Description	DDM reply	Function
  Data stream (DS) in use	STRIUSRM	GET
  Data stream (DS) in use	STRIUSRM	PUT
  Delete document SHDONL(TRUE) specified, but shadow does not exist	EXSCNDRM	DELFIL
  Document in use	FILIUSRM	OPEN
  Document is read only	ACCINTRM	OPEN
  Document not found	EXSCNDRM	DELFIL
  Document not found	FILNFNRM	OPEN
  End of data	SUBSTRRM	GET
  File already open for the declare name	OPNCNFRM	OPEN
  File not open	FILNOPRM	GET, PUT, LOCK, UNLOCK
  Folder in use	DRCIUSRM	OPEN
  Folder not found	DRCNFNRM	OPEN
  Substring not valid	SUBSTRRM	UNLOCK
  Unlocking a region that is not locked	EXSCNDRM	UNLOCK

• To provide better performance, the IBM i target handles the closing document in a manner such that when the document is closing, a command completion reply message (CMDCMPRM) is returned to the client system before the document is actually closed. If the document is damaged during the closing time, the user never receives this reply message unless he views the job log. When the user opens the file again, the updated data might not be there.
• The IBM i operating system does not support wait on the locking data stream function. The user on the client system must handle the wait function.