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How is this implemented on Windows vs OS X?

by jorangreef 11y ago

dkopi 11y ago
It can't. This is the type of features that have to be developed for each OS separately.
- jorangreef 11y ago
  Yes, that's what's I meant, how would you develop it on Windows vs OS X etc? What options are available on those platforms?
  - dkopi 11y ago
    I don't know how dropbox has actually implemented this, and I'm not sure about OSX, But on windows you might use a kernel file system filter driver or a shell namespace extension: https://msdn.microsoft.com/en-us/library/windows/desktop/cc144095(v=vs.85).aspx https://msdn.microsoft.com/en-us/library/windows/desktop/cc1... This looks like an open source project that provides something similar for google drive: https://github.com/google/google-drive-shell-extension https://github.com/google/google-drive-shell-extension On linux this could probably be even easier, just mounting a directory to a remote NFS server.
    - hemancuso 11y ago
      If you look in the Dropbox install the driver is already being distributed on Mac and Windows. It's a filter driver.
      - deleted 11y ago
        [deleted]
gkya 11y ago
My first guess is decoupled drivers with an abstraction that the actual dropbox client service uses. One driver for windows, one for mac. Though I don't know if you can do user mode filesystems on those, but there is this: https://dokan-dev.github.io/ https://dokan-dev.github.io/ Or else they may have used some fs event notification library to intercept access to files, but I think that would be harder (impossible? IDK win32/mac) to do than a filesystem.
_razvan 11y ago
From a first look on Windows, this is implemented with NTFS sparse files [1] and a file system minifilter. The sparse files act as placeholders so that you can browse your entire Dropbox structure. When you access a file, the minifilter sees that and starts fetching the data from Dropbox servers in the background. You can think of it as HSM [2] [1] https://msdn.microsoft.com/en-us/library/windows/desktop/aa365564%28v=vs.85%29.aspx https://msdn.microsoft.com/en-us/library/windows/desktop/aa3... [2] https://en.wikipedia.org/wiki/Hierarchical_storage_management https://en.wikipedia.org/wiki/Hierarchical_storage_managemen...

How is this implemented on Windows vs OS X?

dkopi 11y ago

It can't. This is the type of features that have to be developed for each OS separately.

jorangreef 11y ago
Yes, that's what's I meant, how would you develop it on Windows vs OS X etc? What options are available on those platforms?
- dkopi 11y ago
  I don't know how dropbox has actually implemented this, and I'm not sure about OSX, But on windows you might use a kernel file system filter driver or a shell namespace extension: https://msdn.microsoft.com/en-us/library/windows/desktop/cc144095(v=vs.85).aspx https://msdn.microsoft.com/en-us/library/windows/desktop/cc1... This looks like an open source project that provides something similar for google drive: https://github.com/google/google-drive-shell-extension https://github.com/google/google-drive-shell-extension On linux this could probably be even easier, just mounting a directory to a remote NFS server.
  - hemancuso 11y ago
    If you look in the Dropbox install the driver is already being distributed on Mac and Windows. It's a filter driver.
    - deleted 11y ago
      [deleted]

gkya 11y ago

My first guess is decoupled drivers with an abstraction that the actual dropbox client service uses. One driver for windows, one for mac. Though I don't know if you can do user mode filesystems on those, but there is this: https://dokan-dev.github.io/ https://dokan-dev.github.io/ Or else they may have used some fs event notification library to intercept access to files, but I think that would be harder (impossible? IDK win32/mac) to do than a filesystem.

_razvan 11y ago

From a first look on Windows, this is implemented with NTFS sparse files [1] and a file system minifilter. The sparse files act as placeholders so that you can browse your entire Dropbox structure. When you access a file, the minifilter sees that and starts fetching the data from Dropbox servers in the background. You can think of it as HSM [2] [1] https://msdn.microsoft.com/en-us/library/windows/desktop/aa365564%28v=vs.85%29.aspx https://msdn.microsoft.com/en-us/library/windows/desktop/aa3... [2] https://en.wikipedia.org/wiki/Hierarchical_storage_management https://en.wikipedia.org/wiki/Hierarchical_storage_managemen...