Classic Computer Magazine Archive START VOL. 5 NO. 6 / FEBRUARY/MARCH 1991



Fast And Affordable
Videotape Backup System


Thanks to Seymor/Radix, you don't have to spend hours doing the "floppy-disk shuffle" to back up your hard disk. With the DVT VCR backup system you flow can save all of your hard-disk data directly to video tape.

What You Get
The DVT VCR package contains a 12-page instruction manual, a single-sided disk that includes the backup program and a few utilities, two five-foot RCA cables and a cartridge module. The module plugs into the ST's cartridge port and only needs a couple of inches of clearance from the side of the keyboard for the cables to connect. These cables plug into the Video In/Out jacks on a VCR.

Hard-disk backup
Seymor/Radix Inc.
P.O. Box 166055
Irving, Texas 75016
(214) 255-7490
1MB, hard drive
A fast, efficient and inexpen-
sive way to perform a
hard-disk backup.

How It Works
The DVT backup program requires at least 760K of free RAM to run. A small portion of this is used by the program and the rest is set up as a buffer. When you back up your hard disk, files are copied into this buffer until it is full. This group of files, called a bundle, subsequently transfers to the VCR. This process repeats until the backup is complete. Restoration is accomplished in a similar fashion. The video tape plays until a bundle is read into the buffer. The tape then stops while the buffer's contents are written to the hard drive.

Backups and restores are accomplished in one of two ways: partition or individual file. Partitions can he queued so that an entire hard disk backs up in one operation. You can back up individual files by selecting them one at a time and then sending the bundle of file(s) to tape. A bundle with files selected in this way can contain files from any folder and/or partition.

DVT includes a verify function that checks the integrity of the tape backup and can identify any "audible dropout" areas in a video tape (data written to these areas can be lost because of poor signal retention). In the restore process, the DVT's Audible Dropout Indication will attempt to recover any files that may have been copied to one of these corrupt tape sectors.

Test Run
For an initial test run I chose a 7.2MB partition on my 10MB hard disk. The backup clocked in at a fast 2.4 minutes (20 seconds per megabyte) and was a success - the verify function revealed only one file out of 522 in an audible-dropout area. Fortunately, I was able to recover this file in the restore process.

The VCR speed setting determines the amount of data that can fit on a video tape. According to Seymor/Radix, a common "120" tape holds around 36MB in standard-play mode and up to 108MB in extended-play mode. Always use as high a quality video tape as you can find. Since the backup process is so quick, it can he done every time you power down your computer. This means the tape will he used often. Lower quality tape may wear out faster.

I did run into a few problems with the software. First, the Individual File Restore simply would not work, but I later found out that this may have been a quirk of my system (it worked on other systems I tried and Seymor/Radix was not aware of any such problem).

A few minor annoyances also showed up. During the verify and restore routines, keyboard-clicking sounds were generated at random, and the abort option in the program only worked if a signal from the VCR was being received. The verify routine could only be exited by clicking on Abort, instead of automatically returning to the main menu after all bundles in a backup session had been read. Lastly, the Get Partition Info selection did not display the number of bytes used in a partition, as the manual states it should have. Instead, it displayed the number of files in a partition.

A word of warning: If the video tape runs out before the backup is complete, the DVT program continues to run, since the VCR cannot send a signal for "end of tape." Therefore, make sure there is enough tape to back up all your selected data. The same is true for restore: If your hard disk runs out of room before all files are restored, those bundles received after the hard drive is full will not he restored. TOS will probably give you an error message and the program will keep trying to transfer files even though there is no space available. Fortunately, you can press [Esc] to return to the Desktop to get out of this.

DVT is especially useful
for backing up a hard disk
with a particularly large capacity.

Beat The Backup
If you own a VCR and a hard drive, DVT VCR presents an effective and inexpensive alternative to the important but tedious process of backing up your hard disk (by comparison an ICD FA.ST tape backup costs $1,000). DVT is especially useful for backing up a hard disk with a particularly large capacity (40MB or more). Of course, there is the convenience factor to consider: If you back up your hard disk on a regular basis, you'll find it a hassle to unhook your VCR from your television every time you want to do a backup.

There are a few features that I would like to see added to DVT in the future. Although the files in each bundle scroll on the screen as they copy to the buffer, no record is kept. An option to print out a hard copy, or ASCII file to a floppy disk, listing each bundles' contents as it is backed up, would make it easier to locate individual files. It also would be nice if the DVT program could recognize wild-card characters, rubberband files with the mouse and select files with [Alt]-right mouse button. Any one of these features would make multiple file selection for backups faster and more efficient.

A final recommendation: Though your hard-disk data is very important to you, others may not share your feelings. On family video nights, suggest something with a little more action.

Lance Cluff lives in Anchorage, Alaska, where he works as a mechanical engineer. This is his first appearance in START.