VFAT Plugin for NetDrive


NetDrive plugin for local VFAT volumes. Requires NetDrive.


The VFAT plugin for NetDrive mounts a local Microsoft Windows VFAT volume to the NetDrive file system.

Restrictions of this version of the VFAT plugin:

  • OS/2 extended attributes (EA) are not supported. It is not recommended to use this plugin for volumes with existing EAs.
  • Slower throughput than the OS/2 native FAT file system driver.
  • Only one VFAT resource per mount point.
  • VFAT filename characters, not available to the current codepage, may be corrupted while copying or moving the file.

Limitations of the demo version:

  • Does not support creation of new files on a VFAT volume (SYS0050 is returned when attempted).

Download the demo version here.


NetDrive for OS/2

VFAT file system plugin version 3.0.5

Demo version

(C) Blueprint Software Works, 2000-2008


1. Overview
2. Installation
3. Using VFAT drives
3.1. Removable media, USB memory devices and ndeject.exe
4. Known limitations and problems
5. Revision history
6. Support
7. License agreement

1. Overview

The plugin provides read/write access to a drive with Microsoft
Windows 95 VFAT file system.

VFAT is an extention of DOS FAT file system. The extension
supports long names for files and directories, and retains
backward compatibility with original DOS FAT 8.3 name

The plugin was developed to support all features of VFAT file
system and to be as reliable as possible.

Note: The plugin does not support FAT32 file system.

IMPORTANT NOTE: The plugin directly writes to mounted VFAT
! disks. This can lead to data corruption due to errors in
! plugin code, operating system errors or hardware faults.
! It is important to make a backup copy of all data before
! using the plugin. Be sensible and take a few precautions
! and you might save yourself from potential problems.

Demo version note

The demo version is limited so it does not support creation
of new files on the disk. System error SYS0050 is returned
when a new file is created on the VFAT resource.

Full featured version of the plugin can be ordered at


Information for registered customers

This version is a free upgrade for registered customers
of ealier versions of the plugin.
Please download the new version from BMT Micro download site,
using the download link you have received for your registered

If you have a previous version of the plugin and do not have the
download link, please fill in the online form:


2. Installation

This plugin requires the NetDrive for OS/2 Control Program
version 3.0.1 or higher. The version can be queried using
the following command:


Alternatively you can select ‘Help->About NetDrive for OS/2’
menu item in NetDrive for OS/2 Control Panel. The Control
Program version is displayed in the lower left part of
the message box in between two horizontal lines.

To install the plugin run instpl.cmd

3. Using VFAT drives

The plugin can mount an existing drive with VFAT file system.

Here is an example for using the plugin to access floppy
drive A:. The following commands should be executed:

ND MOUNT FAT S:\floppy A: W

The first command creates a virtual volume S:. Then a mount
point S:\floppy is created and the last command actually
mounts floppy drive A: to the mount point with read/write
access permission.

Now contents of the floppy disk will be available in the
S:\floppy directory. Any files or directories created there
will be actually created on the disk in drive A:.

Note: The plugin locks original drive letter (A: in the above
—- example) to prevent concurrent access from other system
components. Consequently, any attempts to read or write
the disk will result in a SYS0108 error which indicates
that the disk is in use or locked by another process.
These errors may be avoided by adding AUTOFAIL=YES
statement to CONFIG.SYS.

Access to the VFAT file system can be ended by unmounting it
from NetDrive with the following command:

ND UNMOUNT S:\floppy 0

This command will unlock the drive for the system.

Note: When VFAT disk is mounted, the plugin will automatically
—- detect disk changes, but it is not recommended to change
disk while it is being accessed. Doing the change might
lead to data loss.

3.1. Removable media, USB memory devices and ndeject.exe

This version of the plugin is more suitable for removable media
devices than previous version. The problem with old version was
that in order to eject mounted removable media one had to
unmount the VFAT resource before executing eject.exe command.

Here is a recommended method for using removable media: ZIP drives,
USB memory sticks, etc, with the plugin:

* Create a mount point for your removable media, see online
help in NetDrive for OS/2 Control Panel for details.
For example, you may create volume s: and a mount point

* Mount a VFAT resource to the mount point and specify
the drive letter that is or will be used by the removable
For example, if OS/2 will assign drive letter I: to
inserted memory stick, you have to specify I: in the
VFAT resource properties.

* Now when a removable media is attached to the system,
you will be able to access it in the created mount point.

* When you need to eject the removable media execute
ndeject.exe s:\usbmem
This command will perform the same actions as regular
eject.exe utility, but in addition will also tell the
plugin to release the removable media.

* After ndeject, VFAT resource will still be mounted to
s:\usbmem but no files will be there.
When a new removable media will be attached to the
system, you will be able to access it in s:\usbmem
without the need to mount the resource again.

4. Known limitations and problems

The following issues might limit the plugin use:

* OS/2 extended attributes (EA) are not supported.
Existing EA will be retained in place but they will not
be queried or set by the plugin. It is not recommended
to use this plugin for disks with extended attributes.
EA support may be implemented in a future version.

* The plugin is slower than OS/2 native FAT file system
driver. This is in consequence of the facts that
a) the plugin operates on application (ring 3) level
and has to call disk IO system (ring 0) interfaces via
application programming interface that implies
additional overhead comparing to ring 0 native file
system driver.
b) write operations are not cached to insure reliability
and file system consistency.

* The plugin will not mount two or more FAT resources in
the same mount point. Only one FAT resource per mount
point is permitted. However you can create as many
FAT resources as required in different mount points.

* VFAT file name characters, which cannot be displayed in the
current process codepage, can be corrupted while copying
or moving the file.

5. Revision history

—- ——————————————————–
19 December 2008 Version
—- ——————————————————–
FIX Files could have 0 bytes size in with Windows XP.
—- ——————————————————–
10 May 2006 Version
—- ——————————————————–
FIX Wrong filenames in directories with a lot of files.
—- ——————————————————–
23 February 2006 Version
—- ——————————————————–
FIX File names with length 11*n characters written with the
plugin could not be read on some other devices.
FIX Write to FAT12 did not work.
—- ——————————————————–
21 February 2005 Version
—- ——————————————————–
NEW ndeject.exe utility for removable disks and USB memory
NEW Significantly improved performance, especially for write
FIX Some USB memory devices were not recognized as
valid VFAT filesystems
—- ——————————————————–
1 November 2003 Version
—- ——————————————————–
FIX HPFS formatted disks were recognized as VFAT ones
—- ——————————————————–
1 October 2003 Version
—- ——————————————————–
FIX do not assume that a 0xF6 format fill byte marks end of
directory. Only 0x00 marks the end.
—- ——————————————————–
7 July 2003 Version
—- ——————————————————–
FIX Data loss when a file is opened by two or more
threads in the same process
—- ——————————————————–
6 June 2003 Version
—- ——————————————————–
NEW Return drive description in DosQueryFSAttach
—- ——————————————————–
5 June 2003 Version
—- ——————————————————–
NEW initial version
—- ——————————————————–

6. Support

Support is available for registered customers via email.
Please contact us at

e-Mail: netdrive@bmtmicro.net

Developers site is http://www.blueprintsoftwareworks.com/netdrive

7. License agreement

The use of NetDrive for OS/2 VFAT Plugin is subject to the
following terms and conditions.

Demo version

The demo version of the VFAT plugin can be used without any
limitations, so long as this does not violate NetDrive for OS/2

Full version

You may NOT distribute the full version. You may copy it onto
a computer to be used and you may make archival copies of it
for the sole purpose of backing up the software and protecting
your investment from loss.

You may threat your full version just like a book. This means
that the full version may be used by any number of people, and
may be freely moved from one computer location to another,
so long as there is NO POSSIBILITY of it being used at one
location or on one computer while it is being used at another.

Just like a book cannot be read by two different people in two
different places at one time, neither can the full version
of the VFAT plugin be used by two different people in two
different places at the same time (unless, of course,
Blueprint Software Works copyright is being violated).


BMT Micro, Inc., Blueprint Software Works do not warrant
that NetDrive for OS/2 VFAT plugin will meet your requirements,
that operation of NetDrive for OS/2 VFAT plugin will be
uninterrupted or error-free, or that all NetDrive for OS/2 VFAT
plugin errors will be corrected. The aforementioned parties are
not responsible for problems caused by changes in the operating
characteristics of computer hardware or computer operating
systems that are made after the release of NetDrive for OS/2 VFAT
plugin nor for problems in the interaction of NetDrive for OS/2
VFAT plugin with other software. The aforementioned parties have
no responsibility to replace or refund the fee of and media or
license damaged by accident, abuse or misapplication.


(C) COPYRIGHT Blueprint Software Works, 2000-2008.