Accucadd's automatic backup feature: recovering after a "crash"

Accucadd makes periodic backups of the drawing you are working on. This is automatic, and is controlled through the Backup item of the File menu. It is provided as a last-ditch protection, and should not be regarded as your first (or only) defense against losing your work.

Setting the backup frequency is a tough decision, and always a tradeoff. If you backup every minute, you only stand to loose about a minute's worth of work. But – and it's a big but – then you only have a minute (literally) to recover the Latest backup before it is replaced with a newer version. You may think this is what you want. Normally, it is, but in the event of a large error (or "crash"), you could easily be wiping out a perfectly good drawing in the backup file and replacing it with junk. We suggest choosing a value between 5 and 10 minutes as a good balance.

What the automatic backup does

Accucadd makes two independent backups of every page you are working on. Page 1 backups are stored in files with a  .BK1  extension, Page 2 backups have a  .BK2  extension, and so on. At the instant a backup is made, the already existing backup is copied to the file  _!WCBAK2  and the newest backup written to file  _!WCBAK  

Different versions of Accucadd use slightly different names: instead of starting  _!WC  the file names start with _!ac  but they are otherwise identical – please keep that possible variation in mind.

Look in the folder that Accucadd is installed in. On my computer it's C:\Program Files\Accucadd but it might be different on yours. You will see the following four files (but they typically won't be next to one another as they are here):

Directory of C:\Program Files\Accucadd
02/06/03 01:18p  3,745  _!WCBAK.BK1
02/06/03 01:12p    619  _!WCBAK.BK2
02/06/03 01:18p    531  _!WCBAK2.BK1
02/06/03 01:11p    619  _!WCBAK2.BK2

If you now have (or have in the past had) other pages open you may also see additional files with the same naming convention, e.g. _!WCBAK.BK3. This is what these files are used for:

If you have experienced some sort of system "crash" you should be able to make use of the auto backup to recover your work from the backup. After a crash Accucadd will know that it was not properly shut down and you will get a dialog like this:

If you click "Yes" it will automatically load the Latest backup(s) - just as if you had selected File: Backup: Load Backup.

However, if the sequence of events leading up to the problem was like this:

1. your work was corrupted somehow, and then...
2. the automatic backup kicked in, and then...
3. the computer crashed

you will be in the situation where the Latest backup contains trash, although the Second backup should contain valid drawing data.  So when you load the backup (the Latest) you do not get what you expected. Now consider the next step. If you have set the auto backup frequency to one minute, you might well be in the situation where, while you are wondering what has happened, the auto backup process is invoked and the Second backup (which presumably contained useful information) gets overwritten by the auto backup process as described above. This will replace the contents of the Second backup with the contents of the First, and the First will be updated to whatever is now on the screen.

Hence, if you have had a crash, and stand to loose a significant amount of work, it would be worth doing this as soon as you re-start the computer, and before running Accucadd again.

1. make copies of the four backup files listed above, so that you can preserve the contents.
2. run Accucadd and try loading the backup(s) using File: Backup: Load Backup. This will load the Latest backup.
3. If your work is recovered - good - File it NOW!
4. If your work is not there (and remember to check, under the Window menu, to see if it really is there but on another page than the one you are looking at) then shut down Accucadd, and delete _!WCBAK.BK1 and _!WCBAK.BK2
5. make a new copy of the file that you copied _!WCBAK2.BK1 to, in step 1, and rename this new copy _!WCBAK.BK1
6. make a new copy of the file that you copied _!WCBAK2.BK2 to, in step 1, and rename this new copy _!WCBAK.BK2
7. What you have now done, in each case, is to turn the Second backup into the Latest backup, which is the one you get when you use Backup: Load Backup.
8. Now run Accucadd and immediately select File: Backup: Load Backup.
9. Check all pages (Window menu). If your work is recovered - good - File it NOW! If not, then there was no valid backup available.

A useful explicit backup strategy

Since computers and programs can – and do – go wrong from time to time, what I suggest you do is save your work every 10 to 15 minutes by Filing it in the library.  Label each filed drawing with the time (e.g. 10:15, 10:35, 10:45 ) and so on. (You can get the time by clicking in the Information area of the Accucadd status bar, at the screen bottom. The Information area is between the color patch and the units display). The first three or four versions I save as separate files; after that I start to overwrite the oldest one each time, so I always have three or four versions saved. This not only gives me protection against failure but also enables me to go back two or three versions if I suddenly find that I have made a major design screwup.