The Integrated File System - IBM-ILE

A file system provides the support that allows applications to access specific segments of storage that are organized as logical units. These logical units are files, directories, libraries, and objects. There are seven file systems in the Integrated File System:

  • ″root″(/)
  • Open systems (QOpenSys)
  • Library (QSYS.LIB)
  • Document library services (QDLS)
  • LAN Server/400 (QLANSrv)
  • Optical support (QOPT)
  • File server (QFileSvr.400)

Figure illustrates these file systems.

Users and application programs can interact with any of the file systems through a common Integrated File System interface. This interface is optimized for input/output of stream data, in contrast to the record input/output that is provided through the data management interfaces. The common integrated file system interface includes a set of user interfaces (commands, menus, and displays) and application program interfaces (APIs).

The Integrated File System Interface

The Integrated File System Interface

Root File System

The ″root″ (/) file system can be accessed only through the integrated file system interface. You work with the ″root″ (/) file system using integrated file system commands, user displays, or ANSI stream I/O functions and system APIs.

This file system is designed to take full advantage of the stream file support and hierarchical directory structure of the integrated file system. It has the characteristics of the DOS and OS/2 file systems.

Path Names
This file system preserves the same uppercase and lowercase form in which object names are entered, but no distinction is made between uppercase and lowercase whenthe system searches for names.

  • Path names have the following form:
  • Directory/Directory/ . . . /Object
  • Each component of the path name can be up to 255 characters long. The path can be up to 16 megabytes.
  • There is no limit on the depth of the directory hierarchy other than program and space limits
  • The characters in names are converted to Universal Character Set 2 (UCS2) Level 1 form when the names are stored.

Open Systems File System

The open systems (QOpenSys) file system is designed to be compatible with UNIX-based open system standards, such as POSIX and XPG. Like the ″root″ (/) file system, it takes advantage of the stream file and directory support provided by the integrated file system. In addition, it supports case-sensitive object names.

QOpenSys can be accessed only through the integrated file system interface. You work with QOpenSys using integrated file system commands, user displays, or ANSI stream I/O functions and system APIs.

Path Names
Unlike the QSYS.LIB, QDLS, QLANSrv, and ″root″ (/) file systems, the QOpenSys file system distinguishes between uppercase or lowercase characters when searching object names.

The path names, link support, commands, displays and ANSI stream I/O functions and system APIs are the same as defined under the ″root″ (/) file system.

Library File System

The library (QSYS.LIB) file system supports the iSeries library structure. It provides access to database files and all of the other iSeries object types that are managed by the library support.

The QSYS.LIB file system maps to the iSeries file system. For example, the path /qsys.lib /qsysinc.lib /h.file /stdio.mbr refers to the data management file STDIO, in the file H, in library QSYSINC, within the root library QSYS.

File Handling Restrictions

There are some limitations in using the integrated file system facilities:

  • Logical files are not supported.
  • The only types of physical files that are supported are program-described files that contain a single field, and source physical files that contain a single text field.
  • Byte-range locking is not supported.
  • If any job has a database file member open, only one job is given write access to that file at any time; other jobs are allowed only read access.

Path Names

In general,the QSYS.LIB file system does not distinguish between uppercase and lowercase names of objects. A search for object names achieves the same result regardless of whether characters in the names are uppercase or lowercase.

However, if the name is enclosed in quotation marks, the case of each character in the name is preserved.The search is sensitive to the case of characters in quoted names.

Each component of the path name must contain the object name followed by the object type. For example:

/QSYS.LIB/QGPL.LIB/PRT1.OUTQ
/QSYS.LIB/PAYROLL.LIB/PAY.FILE/TAX.MBR

The object name and object type are separated by a period (.). Objects in a library can have the same name if they are different object types, so the object type must be specified to uniquely identify the object.

The object name in each component can be up to 10 characters long, and the object type can be up to 6 characters long.

The directory hierarchy within QSYS.LIB can be either two or three levels deep (two or three components in the path name), depending on the type of the object being accessed. If the object is a database file, the hierarchy can contain three levels (library, file, member); otherwise, there can be only two levels (library, object). The combination of the length of each component name and the number of directory levels determines the maximum length of the path name.

If ″root″ (/) and QSYS.LIB are included as the first two levels, the directory hierarchy for QSYS.LIB can be four or five levels deep.

The characters in names are converted to code page 37 when the names are stored. Quoted names are stored using the code page of the job.

Document Library Services File System

The document library services (QDLS) file system supports the folder objects. It provides access to documents and folders.To work with the QDLS file system through the integrated file system interface, use the integrated file system commands, user displays, or ANSI stream I/O functions and system APIs.

All users working with objects in QDLS must be enrolled in the system distribution directory.

Path Names

QDLS does not distinguish between uppercase and lowercase in the names containing only the alphabetic characters a to z. A search for object names achieves the same result regardless of whether characters in the names are uppercase or lowercase.Other
characters are case sensitive and are used as is.

Each component of the path name can consist of just a name, such as:

/QDLS/FLR1/DOC1

or a name plus an extension, such as:

/QDLS/FLR1/DOC1.TXT

The name in each component can be up to 8 characters long, and the extension can be up to 3 characters long. The maximum length of the path name is 82 characters.

The directory hierarchy below /QDLS/ can be 32 levels deep.The characters in names are converted to code page 500 when the names are stored. A name may be rejected if it cannot be converted to code page 500.

LAN Server/400 File System

The LAN Server/400 (QLANSrv) file system provides access to the same directories and files that are accessed through the LAN Server/400 licensed program. It allows users of the OS/400 file server and iSeries applications to use the same data as LAN Server/400 clients.

To work with the QLANSrv file system through the integrated file system interface, use the integrated file system commands, user displays, or ANSI stream I/O functions and system APIs.

Files and directories in the QLANSrv file system are stored and managed by a LAN server that is based on the OS/2 LAN server. This LAN server does not support the concept of a file or directory owner or owning group. File ownership cannot be changed using a command or an ANSI stream I/O function and system API. Access is controlled through access control lists. You can change these lists by using the WRKAUT and CHGAUT commands.

Path Names
The file system preserves the same uppercase and lowercase form in which object names are entered. No distinction is made between uppercase and lowercase when the system searches for names. A search for object names achieves the same result regardless of whether characters in the names are uppercase or lowercase.

  • Path names have the following form:
  • Directory/Directory/ . . . /Object
  • Each component of the path name can be up to 255 characters long.
  • The directory hierarchy within QLANSrv can be 127 levels deep. If all components of a path are included as hierarchy levels, the directory hierarchy can be 132 levels deep.
  • Names are stored in the code page that is defined for the File Server.

Optical Support File System

The QOPT file system can be accessed through the integrated file system interface. This is done using either the OS/400 file server or the integrated file system commands, user displays, and ANSI stream I/O functions, and system APIs.

Path Names
QOPT converts the lowercase English alphabetic characters a to z to uppercase when used in object names. Therefore, a search for object names that uses only those characters is not case-sensitive.

  • The path name must begin with a slash (/) and contain no more than 294 characters. The path is made up of the file system name, the volume name, the directory and subdirectory names, and the file name. For example:
  • /QOPT/VOLUMENAME/DIRECTORYNAME/SUBDIRECTORYNAME/FILENAME
  • The file system name, QOPT, is required.
  • The volume name is required and can be up to 32 characters long.
  • One or more directories or subdirectories can be included in the path name, but none are required. The total number of characters in all directory and subdirectory names, including the leading slash, cannot exceed 63 characters. Directory and file names allow any character except 0x00 through 0x3F, 0xFF, 0x80, lowercase-alphabetic characters, and the following characters:
  • – Asterisk (*)
    – Hyphen (-)
    – Question mark (?)
    – Quotation mark (")
    – Greater than (>)
    – Less than (<)

  • The file name is the last element in the path name. The file name length is limited by the directory name length in the path. The directory name and file name that are combined cannot exceed 256 characters, including the leading slash.
  • The characters in names are converted to code page 500 within the QOPT file system. A name may be rejected if it cannot be converted to code page 500. Names are written to the optical media in the code page that is specified when the volume was initialized.

File Server File System

The QFileSvr.400 file system can be accessed through the integrated file system interface. This is done by using either the OS/400 file server or the integrated file system commands, user displays, and ANSI stream I/O functions and system APIs. In using the integrated file system interfaces, you should be aware of the following considerations and limitations.

Note: The characteristics of the QFileSvr.400 file system are determined by the
characteristics of the file system that are being accessed on the target system.

Path Names

For a first-level directory, which actually represents the ″root″ (/) directory of the target system, the QFileSvr.400 file system preserves the same uppercase and lowercase form in which object names are entered. However, no distinction is made between uppercase and lowercase when QFileSvr.400 searches for names.

For all other directories, case-sensitivity is dependent on the specific file system being accessed. QFileSvr.400 preserves the same uppercase and lowercase form in which object names are entered when file requests are sent to the OS/400 file server.

  • Path names have the following form:
  • /QFileSvr.400/RemoteLocationName/Directory/Directory . . . /Object

    The first-level directory (that is, RemoteLocationName in the example shown above) represents both of the following:

  • The name of the target system that will be used to establish a communications connection. The target system name can be either of the following:
  • - A TCP/IP host name (for example, beowulf.newyork.corp.com )
    - An SNA LU 6.2 name (for example. appn.newyork ).
    – The ″root″ (/) directory of the target system

    Therefore, when a first-level directory is created using an integrated file system interface, any specified attributes are ignored.

    Note: First-level directories are not persistent across IPLs. That is, the first-level directories must be created again after each IPL.

  • Each component of the path name can be up to 255 characters long. The absolute path name can be up to 16 megabytes long.
  • Note: The file system in which the object resides may restrict the component length and path name length to less than the maximum allowed by QFileSvr.400.

  • There is no limit to the depth of the directory hierarchy, other than program and system limits, and any limits that are imposed by the file system being accessed.
  • The characters in names are converted to UCS2 Level 1 form when the names are stored.

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