Acorn Archive/GetBack
=====================

Archive and GetBack are two tools supplied with Acorn fileservers to
archive and restore data from the file servers. They are fairly badly
written, but they are the only method at the moment of backing up an entire
server onto more than one archive disk in one simple operation.

This version of Archive/GetBack has been repaired to use and display NetFS
dates correctly, and has a particularly horrendous hex printout function
replaced by a much simpler and cleaner one.


Selecting source/destination file
---------------------------------
When creating, examining or extracting an archive file, if using a BBC
Master you can ignore the filing system prompts and override them to read a
file on any filing system, for instance: -net-arcback


Retrieving files/directories
----------------------------
The prompts when extracting are rather confusing.

Pathname of directory to retrieve from:
  This is the pathname within the archive of objects to retrieve. For
  example, if the archive includes "$.CAVE", "$.CAVE.DATA", etc then
  entering $.CAVE.DATA will extract only those entries with "$.CAVE.DATA"
  at the start of their name.

Pathname of directory to retrieve to:
  This is the destination directory to save the extracted files to. This
  directory must exist, and it is prepended to all the extracted filenames.
  For instance, if you enter $.CAVE then the above examples will extract to
  $.CAVE.CAVE, $.CAVE.CAVE.DATA, etc.

Object specifier:
  You can select individual subfiles using the standard BBC filing system
  wildcards * and #. Enter * or just <return> for all files.


File Structure
--------------
Repeated entries {
  n bytes : filename, <cr>
  1 byte  : filetype - 1=file, 2=directory
  1 byte  : disk number - starts at 1
  4 bytes : load address
  4 bytes : exec address
  4 bytes : length
  1 byte  : access byte
  2 bytes : modification date in NetFS format
  2 bytes : modification time hh, mm (no seconds)
  length bytes of file data
  }

Stored filenames are the full path of the entry, usually with an absolute
directory reference, eg "$.CAVE", "$.CAVE.!BOOT". If the filename starts
with '.', the initial '.' is skipped.

Entries can be in any order, but will tend to be in the order that they
were encounted when adding them to the archive.