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updated 28 August 2011

Users of DX4WIN need to be aware that their log is NOT re-written to disk after a QSO is added or modified. Rather, the QSOs are kept in volatile RAM memory until they are written to disk, either initiated by the user, or at timed backup intervals. This application note discusses some of the ways to protect your log.



How does DX4WIN save your log?

Your log file is named <CALLSIGN>.DXL and resides in the SAVE directory of your DX4WIN installation. This file is updated only these ways:
  1. ALT-S while the program is running
  2. Close the active log, DX4WIN prompts you to save the file
  3. Exit the DX4WIN program, DX4WIN prompts you to save the file
Every time that DX4WIN, saves your log, it writes the previously-saved log to a file of the same name with a ~XL extension, for example, AD1C.~XL.

DX4WIN can also be configured to save your log to disk at regular intervals. This is configured in the QSO tab of Preferences, as "Backup (min)". The default is 2 minutes. When your log is unsaved (neither saved nor backed up), the word "Modified" will appear in red in the main DX4WIN program bar, followed by the number of seconds until the log is backed up. Once the log has been backed up, this will change from red to black. The backup file is named DX4WIN.DXB and is stored in the DX4WIN install directory (not the SAVE directory). When DX4WIN writes a new backup file, it renames the previous one to DX4WIN.~XB.

If DX4WIN shutdown unexpectedly, and the backup file (DX4WIN.DXB) is newer than the log file (<CALLSIGN>.DXL), DX4WIN will prompt you to save the backup file as a log file. Be careful:

  1. Use a different name than your current log (I like to use AD1C-1, AD1C-2 etc). Once you are sure that the backup log is the one you want, you can save it using the name of your real log.
     
  2. Make sure to save the log file in the SAVE directory of your DX4WIN installation. Windows has a habit of trying to save things in My Documents by default.

In DX4WIN 8.0x, you can define a secondary backup directory. This is configured in the QSO tab of Preferences, as "Secondary backup directory". You specify just the path to the directory, and every time DX4WIN writes the log to your SAVE directory, it will also write the log to this secondary directory. Be aware that DX4WIN will be "busy" while it is saving the log. If the secondary directory is on a USB or network drive, it may take some time before that write completes. You will not be able to use DX4WIN until the log is saved in both places.


Avoiding Disasters

Unlike paper logging, computer logging does not leave a hard copy anywhere. While you could potentially lose your paper logs due to theft, fire or water damage, data loss due to component failure can be much more frustrating. Coupled with the fact that the newest QSOs may exist for a time only in your computer's volatile RAM memory, it is critical to avoid all forms of potential data loss.

The easiest thing to do is NEVER walk away from your computer while red Modified timer is counting down. Always use ALT-S if you are gone for more than a few seconds.


UPS/Battery Backup

An Uninterruptible Power Supply (UPS) can protect your computer against temporary loss of power. These battery-powered devices have become commonplace, and can often be found on sale at the computer and office supply stores (Best Buy, Staples, etc.). Even the smaller units (350 VA) can give you several minutes of time during which you can save your data and shut down your computer gracefully. More expensive models also include voltage regulation to diminish the effect of voltage sags and surges. If your computer loses power, and your log is not saved, that data will be lost forever.


Real-time Backup Software

Did you ever delete a file by mistake and want to get it back? What about over-writing a good version of a file with a bad one?


Archival and Off-site Backup Solutions

There are two basic tenets of data backup:
  1. You must do it.
  2. If it's not automatic (doesn't require user intervention), you probably won't.

Choose media that's readily available to you and will have enough storage space. Floppy disks, though small and almost obsolete, can do the job if you log is small enough (or can be compressed). Tape drives are still popular in large data centers, but not so much in the home. ZIP disks (100 or 200 MB versions) can be unreliable ("click of death"). Writeable CD/DVDs are one way to go; R/W disks offer more flexibility but the data is not a permanent as on write-once disks. USB "thumb" drives are convenient, but they take longer to write than hard disks. The size of the files associated with DX4WIN is measured in megabytes, not gigabytes, so even a 1GB USB stick will give you plenty of storage. They go on sale often at the office superestores; you should be able to find a new 4GB USB drive for less than ten dollars.

I have a second hard drive in my computer that's used only for backups. It doesn't have to be big, but mine is the same size as the primary drive. This allows me to split it into two partitions, backing up to one partition on the "even" days and the other partition on the "odd" days. The main problem with this solution is that if you lose the computer (crash, theft, act of nature), you lose the backup too. However, you can restore files more quickly from a local backup than from a backup site "in the cloud" (see below), especially when you have a large data set to restore.

Backup software is a matter of personal choice. Choose a title that has a "disaster recovery" strategy where you could, if needed, easily restore your entire hard drive contents, including the boot partition, from the backup. This might mean burning an emergency disk, and this disk may have to be updated every time you install new software. Windows XP and beyond come with backup software (it may not be installed by default). Some other popular products include:

Whereas this protects you against most data loss, it does not protect your data if your media is corrupt, your house catches fire or your computer is stolen. The only to protect against these kinds of disasters is some form of off-site backup. This can be as simple as keeping a copy of a recent backup at your place of employment (assuming you don't work at home). Here are some other possibilities:

Like the backup software described earlier, it's best to automatically back up once a day, usually during a time the computer will be powered on but is not being used.