Questions not in the documentation

[user198379]

A few questions I couldn't find in the documentation, answers I found, and additions that might help:

1) What is "Encrypted filenames wrapping"? It's in target settings > Advanced > Encryption

2) CBC encryption options:
- Document what it is (Cipher Block Chaining). I found this bug report that explains it but I don't see it mentioned anywhere else: http://sourceforge.net/p/areca/feature-requests/253/
- Provide guidelines for choosing CBC or non-CBC encryption. Or eliminate the option if it provides more confusion than value to the user (i.e., choose for the user).

3) *_.hash_decoded files: Document what they are. I found the answer in the this forum, but again most won't ever see it: http://sourceforge.net/p/areca/discussion/587586/thread/3f2ea1c3/

The hash.decoded file simply contains the full encrypted file
name (java way have some problems dealing with long file names, in
some cases).

4) A simple forumula for calculating disk space requirements on the source's drive, the repository's drive, and the drive hosting the temp directory. For example, I don't know how Areca uses its temp folder, or whether it needs extra space somewhere to compress/decompress files.

5) Document the directory structure of backup repositories. Especially if the filenames are encrypted, it's tough to figure out what is stored where. Here's something I put together, but I'm not 100% sure of it and I only have experience with one full backup from one target; not multiple backups from the same target, groups, incremental/differential/image/delta/etc. backups, or other more specialized situations:

          DIRECTORY STRUCTURE

          (Important: These are the notes of a first time
          Areca user. Probably there are several errors
          and certainly many omissions. Corrections and
          updates are very welcome!)

LEVEL
-----
  1       Target Local Repository Root [a]
                        |
            ____________|____________
            |                       |
            |                       |
  2       Archive         areca_config_backup dir
          Root [b][c]     (contains Target config file)
            |
            |____________
            |           |
            |           |
  3       Data     Transactions tracking
          Root         dir
          [b][d]
            |
            |___________________________ ...
            |       |       |       |
            |       |       |       |
  4       Backup data directories [e]

Notes:
------

[a] The dir configured in Target > Edit > Main > Local
    Repository.  Not sure if it's one root per Target, per
    Group, or per something else.

[b] When there's only 1 archive for 1 target, it looks like
    the diagram above. If there are multiple archives for
    one target, including full, incremental, differential,
    or delta backups, I'm not sure how Areca structures the
    directories.

[c] Dir name matches Target Config's "Unique ID"

[d] Dir name may match archive's "Archive name", but the
    directory name is encrypted if filename encryption is
    enabled.  The Archive Name is configured in (Target >
    Edit > Main > Archives' name), and by default is the
    date YYMMDD.

[e] Contain actual files you backed up. Structure:
    - If one source is configured (in Target > Edit >
      Sources), the backup data directory's structure
      matches the source.
    - If multiple sources are configured, then Areca
      matches the sources but eliminates directories they
      have in common.  Example:
            Source 1: c:\one\two\a\b\c\
            Source 2: c:\one\two\x\y\z\
      Produces these backup data directories (directories
      "one" and "two" are common to both, so they are
      eliminated):
            \a\b\c\
            \x\y\z\
      Note that directories, a, b, x, and y will be empty
      except for their subdirectories.