Using standard attributes

Learn about automatically generated directory attributes of the optical file system.

Directory entries for files and directories have information that is associated with them called attributes. Each attribute consists of a name and a value. Some attributes generate automatically when creating the directory or file. These attributes are called standard attributes. Standard attributes start with the letter Q for ease of identification. All file systems use standard attributes. Several receive unique interpretation by the optical file system. LAN-attached optical devices have a different interpretation of standard attributes than directly-attached optical devices. The following is a basic definition of the standard attributes and their meaning with respect to optical support.

QALCSIZE attribute

As an output field, QALCSIZE is the number of bytes allocated on optical disk by the file. It will always be 0 for directories.

When the QALCSIZE attribute is specified on the Open Stream File during a write request, the media is checked to see if there is enough space available to allocate the amount specified. If there is not enough space available on the optical volume, message CPF1F61, No free space available on media, is issued. For more information about using this attribute, see Media Capacity and volume threshold.

QACCDTTM attribute

This attribute is not supported by the optical file system. It is always the same as the file creation date and time (QCRTDTTM).

QCRTDTTM attribute

This attribute indicates the creation date of a file or directory.

QWRTDTTM attribute

This attribute indicates the last date and time that data was written to an optical file. It does not reflect the date and time that the file attributes were last written.

QFILATTR attribute

Support of this attribute is only by directly-attached optical support devices. The optical interpretation of the file flags is as follows:
  • Read-only file: i5/OS™ provides full support of this attribute through the optical file system. When setting this attribute to on (1), you cannot delete or overwrite the file.
  • Hidden file: i5/OS maintains this attribute for the user application to manage, but does not fully support it by the optical file system. When setting this attribute to ON (1), the optical file system does not recognize the file as hidden. User applications require no special access to files with this attribute on.
  • System file: i5/OS maintains this attribute for the user application to manage; but does not fully support it by the optical file system. When setting this attribute to ON (1), the optical file system does not recognize the file as a system file. User applications require no special access to files with this attribute on.
  • Changed file: i5/OS supports this attribute by the optical file system. It is automatically set on (1) when a file is created or written to. You can only set it off(0) by using the Change Directory Entry Attributes (QHFCHGAT) API.