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Date: 16 July 2007

Author: Howard Kaikow <>

Subject: Compare Drives Using File Content program

Download the latest version of the Compare Drives Using File Content program

Also, see the Compare Drives Using File Attributes ("Attributes") program


The Compare Drives Using File Content ("Content") program will create a list of the differences between logical drives. Let us call these the First drive and the Second drive. The program will provide the following information:

Originally, the program was intended to determine which files were included in an incremental/differential backup. This is accomplished by asking a backup program to mount virtual drives that are included in the backup at one point in time, and mounting the corresponding virtual drives from a backup that was done at another point in time.

The program can be used to determine certain differences between various pairs of logical drives. The process will take anywhere from less than one second to many minutes per drive. The choice of buffer size, as well as the fragmentation of the files, and whether anti-virus software is enabled, have a significant impact of the speed of reading the files.


The program outputs a text file for each pair of drives compared. The file will be created in the directory in which you have placed the executable file. The file will be named Bytes-First-Second.txt, where the selected drive letters are used instead of First and Second.


The program was compiled using Microsoft Visual Basic 6 (with SP 6).

In order to run this program, you will need to have the following installed:


I developed the program using Microsoft Windows 2000, and intentionally designed the program so that it will not work on operating systems older than Microsoft Windows 2000. I am aware of only the following restrictions:

Running the program

There is no installation necessary, just directly run the program by double-clicking on the CompareDrivesUsingFileContent.exe file, or by using a shortcut to that file. When you run the program, a Visual Basic 6 Form will be displayed that looks something like the Form below. The Form was designed using a screen resolution of 1280 x 1024. The Form includes the following controls.

Control Purpose
CheckBoxes and SpinControls Select the drives you wish to have analyzed.
Update Drive List If you have added, removed, or changed logical drives while the program is running, you must tell the program to update the drive list.
Buffer Size(bytes) Select the number of bytes to be used in each buffer. Choose among the preselected values, or type in a value of your choosing.
Free buffers Reduces the buffer size to one byte and frees the previously used buffer space.
Update Memory Information Learn how much physical memory is available. This number changes almost continuously while a system is running.
Exit Exit the program.