11/05/2008

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Contents

File Systems

ISO9660

  • This is the file system used on CD-ROMs.
    • · Libraries and players are used to deal with such format.
    • Provides no compression of data.
    • · Limited depth of sub-directories (8 max including root)
    • · Does not support long file names unless we use the Joliet extension filenames that can be up to 64 characters long. This JOLIET ** extension is common on today's Daisy books on cdroms
    • ISO9660 would fit well for audio books and full text full audio books where compression is not really needed as audio is already compressed. Could still be zipped on top of that if needed.


Cramfs

    • Compressed ROM file system. As the name indicates, the data is compressed.
    • · Popular on embedded linux systems but not readily available on all platforms
    • · File sizes are limited to 16MB and File system size is limited to 256MB.
    • Cramfs fits well for text books not much for audio books.


FAT

    • File Allocation Table.
    • · Simple filesystem supported by a large variety of platforms.
    • · Provides no compression of data.
    • · Not very robust

File systems discussion

Streaming

  • Is it possible?
  • Container not really necessary for streaming, especially with a web service protocol.
  • MPlayer / VLC etc can open an DVD ISO for video playback.

Resources

  • Embedded devices with 2MB of RAM can open a CD ISO

Unicode

  • Unicode for content is essential for internationalization
  • DAISY spec doesn't allow unicode file names at the moment
    • Is this needed?
    • May cause problems with players, authoring systems, etc

Backwards compatibility

  • Changes like making file names unicode might make DAISY 4 fundamentally incompatible on devices (even with patches)
  • This may be a decision that has to be made

OEBPS

  • OEBPS defines the layout of a container, and offers both Zip and File System alternatives for the container format
  • [[1]]
  • META-INF directory holds XML files describing the options used in the container (contents, encryption, etc)

Next Meeting

  • TAR
  • More on OEBPS
  • Adobe format, if we can track down the reference
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