DBack (David's Backup application)

The DBack application backs up whole drives, or directory trees. The backup is designed to be quick and easy, and not to stop when individual files cannot be copied (e.g. because they are open in some other application). Filenames are not altered by being stored on a filing system with different filename rules. The backup is relatively friendly towards flash storage devices. DBack multi-tasks very smoothly, no matter how large a file is being processed at any moment.

The companion application DRest is required to restore the data from DBack's backups.

Licence

DBack and DRest are distributed under the GNU General Public Licence, Version 2, a copy of which is supplied in the archive.

Installation

Drag the contents of the archive to somewhere convenient. The Apps dir will do as well as anywhere else.

You will also need:

• the companion DBack application, which should most logically be installed (by the same method) alongside DRest;

• the zlib module, which is part of recent HardDisc4 distributions. If you don't already have zlib, you can get a current HardDisc4 from the RISC OS Open site's Downloads section.

Configuration

There is nothing to configure.

Use

Run the DBack application by double-clicking it. Its icon arrives on the icon bar, with the state showing as "Idle"; click Select on it to open the main window.

The "Source:" writable icon specifies a folder, or the root of a drive, whose data are about to be backed up. Drag a directory to it, then edit it if/as necessary. To back up an entire drive, the entry should end in ".$", so it's easiest to drag in a directory or file from the root directory, then delete backwards from the end until the last character is the "$".

Similarly, the "Destination:" writable icon specifies where DBack will put the backup data. Fill it in using the same method as for the source above. DBack will create the last directory level, if it does not already exist, but only the last level - no more.

You may wish to exclude some files or directory trees from being backed up. For example, it probably doesn't make sense to back up the data from the !Cache application. To exclude items, create a text file somewhere with the items, one on each line; then drag the file into the "Exclude:" writable icon. Note: you MUST put them in a file; DBack treats the exclude entry as a file, not as a literal string. The file can contain up to 100 such exclusions. Any more are ignored, as are blank lines and comments (lines whose first character is a vertical bar).

If you don't want to exclude any items, leave the exclude entry blank.

When you're ready to go, click "Start". DBack performs some checks before starting. If the checks succeed, the state changes to "Running" and the backup is on its way.

Backup operations can be paused by clicking the "Pause" button. The state changes to "Paused" and the button's legend changes to "Continue". This may be useful when backing up to a network destination and you wish to run another application that might single-task the computer for long enough for the network operation to time out and cause an error. The backup can be resumed by clicking "Continue".

When the backup has completed, the state changes back to "Idle" and the summary window opens, showing the total number of files backed up.

To stop a backup, click the "Stop" button. This aborts the backup. It cannot be resumed, it must be restarted. The state changes to "Stopped" as a reminder that the backup did not run to successful completion. A second click on "Stop" brings the state back to "Idle".

Checking the results

The destination directory contains a text file named IndexLog, and at least one data file named 0000, 0001, etc. Open the IndexLog file, which, as its name suggests, contains both the index of the files and directories backed up, and a log of important information such as error messages, when the backup operation was started/paused/continued/finished. This file is just as important as the data files in order to restore the data.

Using your text editor, search for any messages containing the word "Error". (Note that it's quite common to find filenames that contain "Error" - you can ignore these.) If any files could not be backed up, each will have an error entry here. You can take your own copy of any such files, to complete the backup.

Restoring from the backup

The companion DRest application must be used to restore data backed up by DBack. DRest has its own Help file.

Advanced configuration

Having stated above that DBack has nothing to configure, that's not strictly true. Files are stored either as-is or compressed, according solely to their file types. Which file types are compressed, depends on the entries in the CompConfig file. It just might be possible to save a little backup run time, or a little destination file space, by altering entries therein. However, in real life, it's unlikely that you will notice the difference, so I advise against making any changes.

Text files usually compress very well, whereas media files (audio, video) are already compressed to the point where hardly any further file size saving can me made. Compression may or may not save file space, but it definitely takes CPU time, and so does the complementary decompression if a restore operation should become necessary. The biggest unknown is whether Data files should be compressed. This depends on their contents. Currently, Data files are not compressed in DBack's default configuration.

File types that are not specified in the CompConfig file, or are commented out, are not compressed. Entries in the CompConfig file that begin with a vertical bar are considered to be commented out. DBack looks for the first three characters, which specify the hex file type. Any further content on the line should be separated from the file type by a space. In the file provided with the distribution, all 4096 possible file types are listed, followed by their meanings as known on my system at the time I generated the file.

I repeat, you're unlikely to make any significant improvement; so, unless you know differently and you know what you're doing, leave the file alone.

Download

You can download DBack here and DRest here.

If it goes wrong

Contact me by email as dave@davehigton.me.uk and I will do my best to fix the problem.

Revision history

0.02 2017 May 10 First issue

0.03 2017 May 15 Updated help

Page last updated 2017 May 15