UDM - File Systems

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Last updated: Nov 29, 2022 by
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Supported File Systems

Universal Data Mover (UDM) provides a set of consistent capabilities for a diverse set of file systems on many different operating systems.

Platforms can support one or more file systems or file access methods.
 

UNIX

Single hierarchical file system.

Windows

Single hierarchical file system.

z/OS

Three file systems (or file access methods) under UDM:

  1. DSN (data set name, the default when UDM is running under z/OS)
  2. DD (ddname defined by a JCL DD statement)
  3. HFS (hierarchical file system supported by USS)
     
    (See UDM - zOS File Systems for detailed information on z/OS file systems.)

IBM i

Two file systems under UDM:

  1. LIB (default file system)
  2. HFS (hierarchical file system limited to the root and QOpenSys file systems under IFS)
     
    (See UDM - IBM i File Systems for detailed information on IBM i file systems.)

 

UDM behavior is based on a #Common File System (CFS) model, which is biased towards the hierarchical file systems on UNIX and Windows, and the HFS (hierarchical file systems) on z/OS and IBM i.

All transfer operations on a specific server will take place in the current file system of that server. Both servers in a transfer session do not have to be in the same file system. UDM is capable of reformatting data between different file systems.
 

A Stonebranch Tip

The default file system under z/OS is DSN, even if the UDM Manager is executed from USS (UNIX System Services).

Changing the Current File System

To change the current file system on a server, execute the filesys command, which has the following format:

In this format, logical_name refers to the logical name of the transfer server to send the filesys command.

Executing the filesys command with just logical_name returns the current file system of the transfer server.

For z/OS and IBM i, you can specify a file system value (for example: dd, dsn, or hfs for z/OS) after the logical_name to change the current file system on the transfer server.

For Windows and UNIX, which have only one file system, specifying a value after logical_name will result in a warning.
 

Note

A filesys value of dd is available only on z/OS manager for two-party transfer.

Common File System (CFS)

UDM commands attempt to behave in a consistent and predictable manner regardless of the file system or operating system on which UDM is running. In order to do so, UDM behavior is based on a Common File System (CFS) model.

CFS is biased towards the hierarchical file systems found on UNIX, Windows, or HFS (z/OS or IBM i). CFS terminology and commands then are applied to each of the UDM-supported file systems on different operating systems.

Common File System Terminology

UDM attempts to make consist use of file system terminology so that it can be applied consistently to file systems that are not hierarchical.

The following table lists CFS terminology for hierarchical file systems like UNIX, Windows, and HFS.
 

CFS Term

Description

path

Name of a file, which may or may not include a directory. A path is either an absolute path or a relative path.
 
Examples:

  • /home/homer/phone.txt
  • phone.txt
  • ../homer/phone.txt

absolute path

Full path name of a file, starting at the root directory, network point, or drive letter.
 
Examples:

  • /home/homer/phone.txt
  • \\FILESERVER\homer\phone.txt
  • C:\program files\phone.txt

relative path

Path name of a file that is relative to the current working directory.
 
Examples:

  • phone.txt
  • ./phone.txt
  • ../phone.txt
  • myfiles/phone.txt
  • ../homer/phone.txt

file

Name of a file. All files are located in a directory. The name does not include a directory name.
 
Examples:

  • phone.txt
  • editor.exe

directory

Name of a directory. The name does not include a file. It can be absolute or relative.
 
Examples:

  • /home/homer
  • /
  • .
  • ..
  • C:\program files

current directory

Every program that runs on a hierarchical file system has a current directory, also known as the working directory. For most programs, this is the directory from which it was invoked.