VFS is found on most devices running PalmOS 4.x. It can also be found on Sony Clie's running PalmOS v3.5, HandEra (formerly TRG) devices, and Handspring Visors using FlashAdapter compatible Springboard modules.

In addition to the variations on VFS implementations, the wide variety of expansion card brands and formats available adds an additional factor that can influence the performance of operations that use those cards.

Last but not least, utilities that improve the performance of the handheld (such as overclocking applications) can affect VFS performance as well.

With all these variations, it's clear that a standard tool is necessary to measure VFS performance so that users can get an idea of what kind of performance can be expected from different system configurations. That's where VFSMark comes in.

VFSMark measures the following types of expansion card operations:
- creating files
- deleting files
- writing to a file
- reading from a file
- moving to specific locations in a file
- exporting databases to the expansion card
- importing databases from an expansion card
- accessing records in a database on the expansion card
- accessing resources in a database on the expansion card

VFSMark shows the results of those tests relative the performance of a baseline system. The baseline chosen for VFSMark is a Palm m500 with a Palm 16MB SD card running without any overclocking or system performance enhancements.

VFSMark is Free software and full source code is included.