Revise add support for 80 min cd-r (cp 547) Status: Letter Ballot




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CP-641 Date 2006/06/13

Revise add support for 80 min CD-R (CP 547) Status: Letter Ballot



DICOM Correction Item

Correction Number CP-641

Log Summary: Revise add support for 80 min CD-R (CP 547)

Type of Modification

Correction



Name of Standard

PS 3.12 – 2004 + CP 547



Rationale for Correction

CP 547 introduced the larger format (80m – 700MB) CD-R format. It was assuming that the capacity was increased by using a different, less reliable sector format (Mode 2 Form 2).

In fact the capacity is not enlarged by a different record format but the size of the pregrooved spiral track provided by the manufacturer of the empty medium.

The Mode 2 Form 2 sector format is not required and can be removed, leaving a note explaining the low reliability of this format.

A new note that explains the different sizes is added.


Sections of documents affected

PS 3.12 Section F.2.1.1



Correction Wording:


F.2.1.1 SECTOR FORMAT


All DICOM files and all data that comprise the ISO 9660 file system of the DICOM CD-R disc shall be stored either:

  • within Mode 1 sectors, or

  • within Mode 2, Form 1 or 2 sectors with CD-ROM-XA File Number = 0, Channel Number = 0 and Coding Information Byte = 0.

Notes 1.The physical storage capacity of a CD-R disc can be 74 minutes (630 MB) or 80 minutes (700 MB) when using the Mode 1 or Mode 2 Form 1 format. The capacity is fixed by the pregrooved spiral track present on a blank CD-R. Some older CD players will not be able to read the 80 min capacity CD-R discs.

Note: Earlier versions of t2. The DICOM standard prohibiteds the use of Mode 2 Form 2 sectors. These sectors areThis fomat is used to record data on CD-Rs that exceed 74 minute capacity (approximately 630MB) and can also be used for smaller capacity CD-Rs. Some very old equipment may be unable to read CD-Rs recorded with Mode 2, Form 2 sectors. The ability to read this format is determined by both the hardware in the CDROM reader itself and the operating system device drivers. CD-ROM-XA Mode 2 Form 2 sectors do not have sector level error correction. This significantly decreases the reliability of the media and significantly increases the likelihood of data corruption.

It now reads (remove after review):

Notes 1.The physical storage capacity of a CD-R disc can be 74 minutes (630 MB) or 80 minutes (700 MB) when using the Mode 1 or Mode 2 Form 1 format. The capacity is fixed by the pregrooved spiral track present on a blank CD-R. Some older CD players will not be able to read the 80 min capacity CD-R discs.



2. The DICOM standard prohibits the use of Mode 2 Form 2 sectors. This fomat is used to record data on CD-Rs that exceed 74 minute capacity and can also be used for smaller capacity CD-Rs. CD-ROM-XA Mode 2 Form 2 sectors do not have sector level error correction. This significantly decreases the reliability of the media and significantly increases the likelihood of data corruption.




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