UDF 2.00 - OSTA - Optical Storage Technology Association

(indicating a block special device file), OR 7 (indicating a character special
device file).
If the contents of the FileType field in the icbtag structure do not equal 6
or 7, the DeviceSpecificationExtendedAttribute associated with a file shall
be ignored.
In the event that the contents of the FileType field in the icbtag structure
equal 6 or 7, and the file does not have a
DeviceSpecificationExtendedAttribute associated with it, access to the file
shall be denied.
For operating system environments that do not provide for the semantics
associated with a block special device file, requests to
open/read/write/close a file that has the
DeviceSpecificationExtendedAttribute associated with it shall be denied.
All implementations shall record a developer ID in the ImplementationUse
field that uniquely identifies the current implementation.
3.3.4.5 Implementation Use Extended Attribute
struct ImplementationUseExtendedAttribute { /* ECMA 167 4/14.10.8 */
Uint32 AttributeType;
Uint8
AttributeSubtype;
byte
Reserved[3];
Uint32 AttributeLength;
Uint32 ImplementationUseLength; /* (=IU_L) */
struct EntityID ImplementationIdentifier;
byte
ImplementationUse[IU_L];
}
The AttributeLength field specifies the length of the entire extended attribute. For
variable length extended attributes defined using the Implementation Use
Extended Attribute the Attribute Length field should be large enough to leave
padding space between the end of the Implementation Use field and the end of the
Implementation Use Extended Attribute.
The following sections describe how the Implementation Use Extended Attribute is
used under various operating systems to store operating system specific extended
attributes.
The structures defined in the following sections contain a header checksum field.
This field represents a 16-bit checksum of the Implementation Use Extended
Attribute header. The fields AttributeType through ImplementationIdentifier
inclusively represent the data covered by the checksum. The header checksum
UDF 2.00 April 3, 1998
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