VFS: Expansion technology for PalmOS handhelds

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VFS Expansion technology for PalmOS handhelds

• Hal Mueller
• Mobile Geographics LLC

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VFS Virtual File System

• Platform-wide expansion technology many cards,
  one interface
• 4.0 devices and above (mostly)
• Use digital media as external filesystem CF, SD,
  MMC, Memory Stick, Springboard, SmartMedia

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Hardware support mandatory

• Palm m500, m505, m125, m7xx?
• All Sony, Handera, Acer models
• Visor requires Springboard module from Portable
  Innovation Technology (the MemPlug, 4 flavors)
• NOT Palm III/VII, Palm V, Palm m100/105

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External filesystem

• More than just databases
• Files, directories
• Standard file formats
• Interchange with other devices external drives,
  digital cameras

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API calls for VFS

• VFSDirCreate
• VFSExportDatabaseToFile
• VFSFileClose
• VFSFileCreate
• VFSFileDBGetRecord
• VFSFileDBGetResource
• VFSFileDBInfo
• VFSFileDelete
• VFSFileGetAttributes
• VFSFileGetDate
• VFSFileOpen
• VFSFileRead
• VFSFileReadData

• VFSFileRename
• VFSFileResize
• VFSFileSetAttributes
• VFSFileSetDate
• VFSFileSeek
• VFSFileWrite
• VFSGetDefaultDirectory
• VFSImportDatabaseFromFile
• VFSVolumeEnumerate
• VFSVolumeFormat
• VFSVolumeMount
• VFSVolumeSetLabel
• VFSVolumeSize

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VFS uses

• Raw space backups, app storage
• Non-PDB files JPEG, Shapefile, HTML, plain
  text, proprietary formats
• Copy and run (run from card)
• PDB readonly access, overflow
• Image/video/music playback

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Memory overflow

• Infrequently used applications
• Extra DOC files, ebooks
• Extra databases

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Run an app from VFS

• Card appears as category in Launcher
• Select the card, tap an application icon
• PalmOS copies the app into memory, launches app,
  deletes from memory
• Application preferences and databases remain in
  memory
• No app support required unless multifile app
  (bundle bit)

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Backup and restore without Hotsync

• Dump entire PDA memory to VFS
• Restore from VFS after memory loss
• External app required FileZ, BackupPro,
  BackupBuddy VFS, FAFileMover (FlashAdapter)
• Make sure a copy of backup app is on a VFS card!

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Direct program access

• Read/write standard file formats from PalmOS app
  images, maps, text, proprietary formats
• No 64k chunk limit, no 64k record limit, no 4k
  text limit
• What about backup?
• Read PDB from VFS (no copy, no write)

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Possibilities

• Mapping software
• Reference books medical, legal, travel
• Legacy database formats
• Image viewers, movie players, music players

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Demo QA