FillDisk

FillDisk is a tiny and powerful software application that continuously creates empty files in any specified drive or directory until halted by the user, or until the disk is full. These items are filled with zeros (the 0 character).
This type of utility can be used for running various tests on the computer. For example, you can check the efficiency of a disk defragger or the speed of an antivirus tool. It's suitable for reviewing any program dedicated to files.

Download and run the .exe

It's based on a single executable file that you can save anywhere on the disk to run FillDisk with minimum effort. Worth noting is that it doesn't need any DLLs to run, doesn't create additional files on the disk without your permission, and keeps the configuration settings stored in this .exe. by copyiing it to a USB flash drive, you can effortlessly launch the app on any PC.

Generate a DAT file with zeros

Its interface consists of a single window, where all available options are neatly organized. By default, the utility wishes to generate random data in the same location as the .exe, but this can be changed into another drive or folder.
Furthermore, it optimizes the OS by default to speed up the task, but you can disable this option to make it more efficient, although it takes longer. The process is triggered with one click.
The application creates a DAT file in the specified location and keeps adding zeros to it until you cancel the job or the disk remains out of space. In the main window you can check out the disk's cluster size and free clusters, along with the elapsed and remaining time.

Evaluation and conclusion

It was surprisingly speedy in our tests. Evidently, this depends on the hardware configuration of the computer. No errors popped up and it didn't hang or crash. In conclusion, FillDisk is a simple-to-use and reliable tool for generating random content for testing purposes.