Double Image 3.22

Save space on your backup media

Host Interface advertises Double Image 3.22 as an easy-to-use backup and copy program that saves space on any disk storage media, including write once, read many (WORM) drives, hard disks, 3.5" disks, network drives, optical jukeboxes, flopticals, or removable media. The software supports delta backups (i.e., backs up only changed files) by performing bit-by-bit file comparisons and appending new data to already-backed-up files. In addition, Double Image—in conjunction with St. Bernard Software's Open File Manager—can copy open files.

Double Image arrived on two 3.5" disks that included software for Windows NT and Windows 95. I installed the NT version on a 300MHz single-processor system with 128MB of RAM and one 4.3GB hard disk. The installation was easy and required a reboot.

I accessed Double Image's main console, which Screen 1 shows, from the Start menu. Most of the user interface's (UI's) options are easy to understand. Browse buttons adjacent to the Source and Destination fields let you search through a treeview for the directory that you want to copy. I was disappointed that I could browse to only the subdirectory level and not the file level. Using wildcards, you can create a file mask that lets you select specific types of files, but you can use only one mask per path. And because you can't browse to the file level, you must be sure that the files you select exist and you must know their extensions. The only way to select dissimilar files is to create a batch file, which can be time-consuming and potentially damaging.

Double Image lets you use Universal Naming Convention (UNC) and shared drive-letter paths to copy files from other systems on the network. You can copy hidden files, system files, and subdirectories, and you can copy files with certain dates and times. These options add up to impressive functionality, but they also contribute to a crowded interface. No default settings exist, so you must select your preferences the first time you use the program.

I clicked Browse next to the Source field and selected a directory on the system's root drive. I entered the path to the CD-Rewritable (CD-RW) drive and included a directory I created called Test, which included word processing, spreadsheet, and image files. I selected the archive, hidden files, and subdirectory copy options, then clicked Go to initiate the file copy. The files seemed to copy quickly; however, copy speed depends on the source and destination directories' media, speed, and location. To test Double Image's delta-backup ability, I edited 10 Microsoft Word documents in the Test directory and deleted 8 image files from the same directory. When I clicked Go, the software correctly updated the backed-up Word files and deleted the 8 image files.

If you want to achieve more than simple directory transfers, you must wade through confusing instructions about creating command-list files and batch files. To reduce creation time and limit mistakes, Host Interface needs to consider a GUI or wizard that assists in creating command-list files. Although I created a working file that copied multiple directories, the process cost me a few blood pressure points.

As a copying program, Double Image works well, but its shortcomings as a backup product limit its use to small networks or organizations. The program easily copies single directories but has trouble copying multiple directories or files from a variety of locations. Double Image has potential, but other similarly priced programs, such as Stac's Replica, don't require you to create cumbersome scripts. You can purchase the Multi-Session version of Double Image, which lets you run up to 32 copies of the program simultaneously, but I recommend that you wait until the product matures before you purchase it.