Specifies size of XMS cache in KB
/N Disable compressed file support
/X Disable extended int 13 support
/V Verbose Example:
NTFSDOS /L:ge /C:1024
This command has NTFSDOS mount the first NTFS partition it finds as
drive 'g' and the second as drive 'e', and indicates that it should
create a 1MB XMS cache. If a drive letter is specified that is
already in use, the partition that is being mounted at the letter
will not mount and an appropriate error message will be printed.
There is no way to unload NTFSDOS from memory once it has started.
If You Have Problems Running NTFSDOS
====================================
* NTFSDOS does not recognize my NTFS drive
NTFSDOS does not handle cluster sizes > 4K on NT 4.0 formatted drives. This
is rare, since NTFS compression does not handle these cluster sizes either.
NTFSDOS requires that disks be accessible via BIOS, using the INT 13 or
extended INT 13 services. In some cases, SCSI drives may not be fully
accessible without a DOS device driver (see your SCSI adapter documentation).
* NTFSDOS uses too much conventional memory
Some people have complained that NTFSDOS is a memory hog. Unfortunately,
this fact is largely imposed on us by the architecture of NTFS itself
(sorry, but its a *little* more complicated than FAT, and much more memory
intensive), coupled with our desire to provide reasonable performance
across a wide variety of NTFS installations. In general, the footprint
of NTFSDOS increases largely with the clustersize of the largest NTFS
partition, and slightly with the number of NTFS volumes mounted. If the
NTFS drives you will be accessing do not contain compressed files, you
should use the /N option to lower NTFSDOS' memory footprint.
* Accessing an NTFSDOS drive causes a hang or crash
NTFSDOS does not support disk striping. Further, it cannot handle drives
that are on partitions extending beyond the 2GB boundary, or that
are larger than 2GB in size, UNLESS the computer's BIOS has extended
INT 13 support for the drives in question. The latter restrictions are due to
limitations in standard disk BIOS code that prevent it from addressing
sectors 2GB or more from the start of a disk.
NTFSDOS has not been thoroughly bullet-proofed against corrupt NTFS
drive data structures, so it may cause Windows to crash or hang
when it runs into problems. To insure that a crash or hang is due
to a problem with NTFSDOS rather than your NTFS drive, be sure to
chkdsk the drive from Windows NT and try NTFSDOS again.
* Starting programs or loading files seems very slow
Access of large compressed files may be noticeably slower than of
their non-compressed versions.
* File times are not correct when running under DOS 7.0 without Windows 95
This problem is due to the fact that NTFS and LFN FAT time stamps are
stored in Coordinated Universal Time (UTC), which is based on Greenwich Mean
Time, and Windows 95 automatically converts times stamps returned by LFN
calls to local time. Since local time zone information is not accessible
outside of Windows 95, running NTFSDOS under DOS 7.0 without Windows 95
results in the display of unadjusted times.
* Programs complain about not being able to find files when they are
there
A directory listing of files that have no short filename will result
in the short filename field of the listing being blank (see the file,
"newlongfilename," in the sample listing above). Changing the current
directory to a path where any component of the pathname does not
have a short filename will result in all short filename calls failing
while in the directory. This makes most Windows 3.1 and DOS programs and
many DOS commands (e.g. MORE) inoperative in these directories. However,
LFN calls are supported in these directories.
* Data read from a file appears to be corrupt
Since this work is based on reverse-engineering rather than official
Microsoft specifications (which are reportedly available under special
circumstances for large amounts of money), we do not guarantee data
integrity of NTFSDOS drives. This is especially important if you are
considering using NTFSDOS as a file backup utility.
* Files or directories seem to be missing
Remember that files and directories that were created with no DOS 8.3
short filenames will not be visible if you are running DOS versions earlier
than 7.0.
* You get the message "No drive letter to mount NTFS partition..."
If NTFSDOS complains that it cannot mount a drive because there
are no available drive letters, you must find the line in your CONFIG.SYS
that begins with "LASTDRIVE=". If you do not find one, then add one. Set
the LASTDRIVE variable to a letter that is greater, by the number
of NTFS drives on your system, than the largest drive letter you normally
have under DOS/Windows. For example, if the highest drive letter normally
in use is E: and you have two NTFS drives, set LASTDRIVE to G: with a
statement in CONFIG.SYS like:
LASTDRIVE=G:
If you still get the message then increment the letter and try again.
Remember to reboot after every change to CONFIG.SYS.
* You get the message "Could not allocate XMS or conventional cache"
Memory usage on your machine is so high that NTFSDOS could not allocate
64KB for a conventional cache. Try removing unnecessary TSRs and drivers
and/or running a DOS memory optimizer or manager.
* XCOPY does not work in a DOS box
XCOPY will not work on NTFS drives that are mounted in DOS boxes under
Windows 95 (e.g. running NTFSDOS in a DOS box). This is because you
cannot run Windows programs off of non-global drives, and under Windows 95,
XCOPY starts the Windows console program XCOPY32.EXE.
Reporting Bugs
==============
When you report a bug (see Reaching Us, below), please provide the following
information about your system:
- disk types (IDE, etc.)
- disk and partition sizes
- BIOS version
- drive sizes and formats
- version of NT that was used to format NTFS drives
- version of NTFSDOS you are using
- an output dump of NTFSDOS run with the /V (verbose) option.
- version of DOS and/or Windows you are running NTFSDOS on
Implementation
==============
NTFSDOS scans the system's partition tables looking for partitions
that have the NTFS attribute byte. When it finds one, it looks for an
unused DOS driver letter and registers a network drive on it. After
it completes the drive search it hooks the network redirector
interrupt and goes resident. Requests come into NTFSDOS as full path
names, or continuations of a previous directory traversal (as with
findnext), so it proceeds to determine where, based on NTFS internal
data structures, the target file is located. When it retrieves the
header for the target file it can determine where the file's data is
located, and read it when it receives requests to do so.
To provide long filename support (LFN), NTFSDOS hooks INT 21/AH=0x71
calls and implements LFN functionality when it sees an LFN call.
Under Windows 95, NTFSHLP.VXD is required to send LFN calls down to
the NTFSDOS for it to process; otherwise NTFSDOS would not see LFN calls
since Windows assumes DOS redirected drives do not provide LFN support.
NTFSDOS also uses the INT 2F/11 and INT 13 APIs. Otherwise the magic is
just memory and cache management plus interpretation of the NTFS on-disk
structures.
Reaching Us
===========
We would appreciate any feedback you have concerning this utility
including suggestions and bug reports. Mark can be reached at
mark@osr.com, and Bryce can be reached at cogswell@cs.uoregon.edu.
Acknowledgments
===============
We thank everybody that e-mailed us with bug reports and other feedback.
Significant understanding of the NTFS file system layout was derived by
studying the Linux-based NTFS driver code maintained by Martin von Loewis.
We acknowledge his indirect contribution to this endeavor.
Andrew Schulman, et. al.'s, book, Undocumented DOS 2nd Edition
(Addison-Wesley), was invaluable in providing network redirector
information necessary for implementing NTFSDOS.
