All approved UDF 2.60 DCNs
All approved UDF 2.60 DCNs
All approved UDF 2.60 DCNs
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<strong>All</strong> <strong>approved</strong> <strong>UDF</strong> <strong>2.60</strong> <strong>DCNs</strong><br />
Figure 3 below illustrates track layout on media after files have been recorded (note that<br />
– in this case – the Metadata Mirror File is not being recorded). In this illustration, Track<br />
#2 is in the used state; hence Track #4 was allocated for additional recording of metadata<br />
(Track #3 is being used to record data).<br />
Track #1<br />
(used)<br />
Track #2<br />
(used)<br />
Track #3<br />
(used)<br />
Track #4<br />
(reserved)<br />
Track #5<br />
(reserved)<br />
Track #6<br />
(used)<br />
Spare Area<br />
Volume Structure<br />
Metadata File FE<br />
Metadata Mirror File FE<br />
File Set Descriptor<br />
File Entry (root directory)<br />
. . .<br />
FE (Data-A)<br />
FE (Data-B)<br />
. . .<br />
Data-A<br />
Data-B<br />
root directory<br />
File Entry (Data-C)<br />
unrecorded area<br />
Data-C<br />
unrecorded area<br />
AVDP<br />
Spare Area<br />
Metadata File extent<br />
Metadata File extent<br />
Volume Space<br />
Figure 3: Recording data on medium (no Metadata Mirror File)<br />
6.x.3 Requirements for <strong>UDF</strong> Implementations<br />
<strong>UDF</strong> implementations are expected to conform to the following requirements:<br />
• For sequentially recordable media formatted for Pseudo OverWrite, the Access<br />
Type in the Partition Descriptor shall be set to zero (pseudo-overwritable), see<br />
section 2.2.14.2<br />
• The Unallocated Space Bitmap and Unallocated Space Table shall not be<br />
recorded<br />
• The Metadata Partition Map shall be recorded<br />
• The Metadata Bitmap File shall not be recorded<br />
• Up to 4 tracks can be concurrently in a “reserved” state<br />
• Multisession /Multiborder recording shall not be used with Pseudo OverWrite<br />
6.x.4 Implementation Notes for <strong>UDF</strong> Implementations<br />
• Query the drive to determine whether a pre-formatted medium supports Pseudo<br />
OverWrite. At format time, set the pseudo overwrite attribute on the medium (as<br />
per <strong>UDF</strong> implementation policy).<br />
• Writing data to previously unrecorded sectors will require querying the drive to<br />
determine the NWA in a track – the returned value will be an absolute logical<br />
sector number (relative to LSN 0 in the volume space).<br />
• Do not attempt to re-use sectors previously allocated to a file marked for<br />
deletion.<br />
• Minimize the amount of data being overwritten.<br />
<strong>All</strong> <strong>approved</strong> <strong>UDF</strong> <strong>2.60</strong> <strong>DCNs</strong> 34 February 28, 2005
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