DX4WIN Data Protection Strategies

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:

ALT-S while the program is running
Close the active log, DX4WIN prompts you to save the file
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:

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.
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.

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 minute.

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?

Undelete Software

Undelete software often takes place of the "recycle bin" and allows you to save multiple deleted copies of a file. This means you can recover something that may have been deleted days or weeks ago. One such product is Undelete by Executive Software.
Automatic Backup

One simple way to back up files in real-time is to use software that saves a copy of a file each time it changes. It may overwrite the previously backed-up version, or save multiple copies. While this is not a complete solution like a full backup, it is usually transparent to the user (when configured correctly). One such product is Iomega Automatic Backup. Personally, I prefer the simplicity of the older version (1.02) over the latest version.

Archival and Off-site Backup Solutions

There are two basic tenets of data backup:

You must do it.
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 space. Floppy disks, though small and almost obsolete, can do the job if you dataset 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. My recent favorite is to have a second hard drive in your computer that's used only for backups. It doesn't have to be big, but I make mine 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.

Backup software is a matter of personal choice. Make sure to 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.

While this protects you against most data loss, it does not protect you 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 office (assuming you don't work at home). Here are some other possibilities:

Use two external hard drives (USB/Firewire/SCSI) for backup. Once a week, swap the hard drive on your computer with the one you keep off-site (office, safe deposit box, etc.).
Your ISP may provide disk space for personal web pages. Usually this is limited to 10-20MB. You will need to FTP the data to your ISP unless they provide a more automated way of transferring it.
Open up a Gmail or Yahoo! Email account and mail yourself the files you want to backup. These accounts typically give you 2GB of space.
Use an off-site service for backups. These are not free (the price structure is usually tied to the amount of storage you require), or may have upload/download restrictions. Here are some to consider:

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