Archive/GetBack File Format
===========================

As used by the Archive/GetBack programs by Acorn originally for
archiving/restoring fileserver and hard drive contents.
http://mdfs.net/Apps/Archivers/Acorn.

The format of a GetBack archive is as follows:
   Repeated for each file:
        name$   : cc cc ... 0D : Filename, terminated with <cr>
        type%   : nn           : File type - 1=file, 2=directory
        sequ%   : nn           : Disk sequence number, starts at 1 for first file
        load%   : lo mm nn hi  : load address
        exec%   : lo mm nn hi  : execute address
        len%    : lo mm nn hi  : length
        access% : xx           : access byte
        mdate%  : lo hi        : modification date in NetFS format
        mtime%  : hh mm        : modification time (no seconds)
        The bytes of the file

Stored filenames are in Acorn format, ie '.' directory seperators, and 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.