Universal Disk Format

The Universal Disk Format (UDF)

The Optical Storage Technology Association (OSTA) has developed a file system format specification to address these problems of complexity and full data interchange. The goal of the OSTA Universal Disk Format (UDF) specification was to develop a practical subset of the NSR standard that would be much easier to bring to market, while also addressing how data is to be interchanged between systems. OSTA specifically defines what information shall be recorded on disk for a particular operating system and how other systems are to treat this information.

UDF was developed by an industry consortium of leading technology companies in the computer storage industry including: HP, Microsoft, Philips, Sony and IBM. Numerous experts have invested significant time in developing a document that would meet the above objectives. As an industry consortium OSTA is not hampered by the restrictions placed on International Standards Organization (ISO) standards. This fact has allowed OSTA to develop a specification that is a significant advancement towards the goal of data interchange between operating systems.

The Ideal Choice for Archiving

Ask yourself these questions:

  • What operating system will I be using 10 or 20 years from now?
  • What hardware platform will I be on?
  • If I store massive amounts of data today, what will I do if I can’t read it on my machine of tomorrow?

Chances are you cannot answer these basic but very real concerns with total certainty this is the very reason UDF was developed. UDF provides the long term assurance that your archived data can be read many years down the road thus protecting your valuable information while maintaining full compliancy with regulations and laws governing information retention.

ISO standard optical media gives the assurance that you can access your data in a wide variety of different optical drives. The ISO standard NSR file system gives the assurance that you can have data interchange among today’s wide variety of different operating systems and the operating systems of tomorrow. Optical storage standards provide assurance that today’s data will be available beyond tomorrow.

UDF Features:

  • Built on the foundation of the ISO/IEC 13346 standard:
  • A practical subset of the ISO/IEC 13346 standard;
  • Fully compliant with ISO/IEC 13346.
  • Simple and universal, defining support for multiple operating systems:
  • Defines what information must be stored on disk by all operating systems;
  • Defines what information must be stored on disk for each particular operating system;
  • Defines how information stored on the disk by one operating system is to be processed by another operating system;
  • Provides support of, and data interchange among, the major commercial operating systems, including:
    • DOS
    • Windows
    • Linux
    • OS/2
    • Macintosh
    • UNIX (POSIX)
  • Expandable to include support for future operating systems.

UDF has been selected as the file system for 2nd generation high capacity CD-ROM, CD Recordable and CD Erasable disks. This includes Digital Video Disc (DVD), the first consumer application use of 2nd generation CD-ROM. Through the use of UDF, DVD entertainment based and computer based content can reside on the same disk and be accessed by a wide variety of computer systems as well as the consumer DVD player in the home. UDF was designed to meet the mass storage needs of a global community well into the future.

Application Level Interchange

Once you have sector and file interchange you can move data among different optical drives on different computers with different operating systems. File interchange allows you to see the same directories and files on the different computers. The next level of data interchange is Application Interchange which deals with the file formats supported by the individual application.

For example, assume that you have sector and file interchange between a PC running DOS, and a Macintosh running MacOS. You can copy files to an optical disk on the Macintosh, bring that disk over to the PC and see the Macintosh files when listing the appropriate directories. Assume further that you used a database application called ALPHA on the Macintosh to create the files on the disk, and you wish to read access those files on the PC using a database application called BETA. Unless ALPHA and BETA use the same file format, you will not be able to read the data written by ALPHA with the BETA program. To have interchange between applications, they must use the same application standards and the same file format.

There currently exists a wide variety of file format standards that allow application interchange. There are database file format standards such as DBF, DIF and RTF. There are image file format standards such as TIFF, PCX, GIF and JPEG. There are audio file format standards such as WAV and VOC. Applications that support standard file formats will be able to interchange data at the application level.

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