In addition to a file's name and data contents, there may exist information about access control, ownership, visibility, icons, application bindings, and other "meta data". The nature and extent of this information varies between platforms.
At the very least, SyncDat will preserve a file's name and the time of its last modification. It will also attempt to preserve its unix access mode, user id, and group id. Windows does not support this extra information.
Preservation of user ID numbers and some group ID numbers may require that syncdat and/or servedat be run as the root super-user.
Unix user and group ids are numbers which are likely to have different meanings on different systems. You should not rely on ID preservation unless you know that the local and remote systems have coordinated ID numbers.
SyncDat will not preserve other Mac OS X meta data, including access control lists and resource forks. It will also not preserve Windows access control lists or file visibility.
Windows' Read-Only flag is preserved and will be treated as mode 0444 on unix systems. Files copied from unix to Windows will have the Read-Only flag set only if no write mode is set.
The Mac OS X locked flag, like other BSD flags, is not preserved.