Backs up/restores Win95 long filenames in DOS.
Version 2.7
Copyright © 1995, 2002 D.J. Murdoch

New in this release
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Also online: an HTML version of the documentation.


DOSLFNBK backs up long filenames and file attributes, to allow you to use older DOS-based backup and archive programs with Win95/98. It also makes it possible to recover from a catastrophic disk crash without re-installing Win95/98 first. Runs on FAT file systems in DOS, Win95/98 or Windows NT.

Microsoft's Windows 95 introduced long filenames (LFNs), and they are mostly compatible with old software. However, there are some problems. Old backup programs don't recognize LFNs, so they don't get properly backed up. Worse, the Win95 backup program didn't support a lot of common backup hardware (e.g. Colorado Memory Systems tape drives using accelerator cards) and wouldn't run in DOS mode, so recovery from a catastrophic disk failure could be really difficult.

To address this problem, Microsoft put a program called LFNBK on the Win95 CD ROM to back up your LFNs. However, it's very inconvenient to use. It requires changes to your Control Panel settings before and after use, and it works by stripping all the LFNs off your disk---so you need to restore them again after you've done your backup to tape. It will only run after Win95 has booted, so again you've got big problems after a catastrophic disk failure.

If you've got a program that is completely incompatible with LFNs then you might want to use LFNBK, but for routine system backups it's too much of a pain.

I wrote DOSLFNBK to address these problems. It runs in any version of DOS that can see your disk, and can both backup and restore your filenames there. During backup, it makes no changes to the names, so you can routinely run it just before a tape backup and not have to undo the damage afterwards. It also allows partial backups and partial restores.

Nowadays, backup programs are a lot smarter: you may well have a Windows backup that can do a full restore from DOS. Even if so, you might choose to use DOSLFNBK for setting up new PCs or in other situations where it's just not convenient to work in Windows.

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New in This Release

Versions 2.1 to 2.3 of DOSLFNBK fixed serious but fairly rare bugs in 2.0. Versions 2.4 to 2.7 fix some rare but irritating bugs, and add a few new features, as described below. Version 2.0 fixed a few minor bugs, and added a lot of new stuff. The main additions are the following:

Version 2.7:

Bug fix for rare directory corruption by DOS

Version 2.6:

Bug fixes for very large directories

Version 2.5:

Adds support for very large FAT16 disks
This version adds support for cluster sizes greater than 32K, as you would get on a FAT16 partitions that are bigger than 2GB.

Version 2.4:

Adds /q option for quiet run
Won't print actions as it does a restore.
Adds /h option for high level access
You can now do a backup from a non-FAT disk, as long as Windows is running. This allows backup of a network drive, for instance.
Fixes rare bugs on very large disks

Versions 2.0 to 2.3:

DOSLFNBK became shareware
I originally wrote DOSLFNBK for my own use, and since I had a lot of help and suggestions from various people around the net, I released it as freeware. However, I get a lot of questions and requests for help, and I can no longer afford the time spent answering those, so the new release is now shareware. If you use it, you are required to obtain a license.
Version 1.6 (still available) will remain as freeware, but I will no longer be offering technical support for it. You're welcome to use it for free into the indefinite future, but please don't ask me for help.
Backup/restore/display of file attributes
Win95/98 use some combinations of file attributes that confuse older backup programs. DOSLFNBK can fix the errors caused by improper restore of these attributes.
Check for full restore
Many programs (e.g. XCOPY) will skip certain files during a backup or restore operation, leading to bizarre errors. DOSLFNBK now compares the list of files on disk to the list in its backup file; if any files are missing, it prints a warning. (It would be nice if it could restore them, but it only backs up the name!) To help support this option, I've added the /all option, which will make DOSLFNBK back up every filename on your disk.
Integrity checks of disk structure
A lot of old disk utilities (especially defraggers and directory sorters other than LFNSORT) will mess up your disk. DOSLFNBK now detects this damage, so that it doesn't make things even worse. It will optionally attempt repairs, but I strongly recommend using dedicated software for this.
Optional overwrite of existing LFNs
Some versions of DOS (e.g. Hebrew DOS) use LFNs for holding special non-ASCII characters in 8.3 filenames. DOSLFNBK can't tell the difference between these LFNs and real ones, so it needs to be able to overwrite names on demand. Use this carefully: the base name of a file can change even when you copy the file from one directory to another, so it's often best just to skip over existing LFNs.
Better display of special characters
LFNs store filenames using the 16 bit Unicode character set, but DOS only knows various 8 bit code pages. DOSLFNBK now does a better job of displaying filenames using special characters.
Restore from a different directory
Sometimes people need to restore filenames to a different directory than the one where they were backed up. The new /from option allows you to do this.
FAT32 support
The late releases of Win95 and Win98 support partitions on hard disks larger than 512 Megabytes. They do this by making fairly substantial changes to the internals of the disk storage, including changing the File Allocation table from 12 or 16 bit entries to 32 bit entries. DOSLFNBK now supports FAT32.
Support for non-IOCTL drives
Some older tape drives and ramdisks pretend to be a disk drive, but don't support all the DOS services to provide information about themselves. DOSLFNBK normally takes a very conservative approach: if it can't get disk information confirmed from two sources, it won't touch the disk. New in this release is the option to go ahead based only on partial information. Use this carefully!
Automatic operation
Sometimes you don't want to sit there answering prompts about questionable situations. DOSLFNBK offers two choices: /auto tells it to automatically give the safe response (which might be to abort the run, with an error code); /force tells it that you know what you're doing, and you want it to go ahead, even if it doesn't look safe.

Bug fixes

The following bugs in older versions have been fixed in version 2.7:

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DOSLFNBK version 2.7 is available by clicking here.

The freeware version 1.6 is available by clicking here.

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DOSLFNBK is *not* public domain software. Releases up to version 1.6 were freeware, and you may use them at no charge. However, the current release is shareware. You may use it at no charge for an evaluation period of 30 days only.

You are free to distribute unmodified copies of the complete DOSLFNBK package, provided your total charge is no more than $1. The total cost of a compilation (e.g. a CD ROM) including DOSLFNBK must be no more than $1 per package in the compilation.

To continue to use DOSLFNBK beyond the 30 day evaluation period, you must register it.

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There is only one kind of license currently available:

$10 simple registration
This registration fee gives you a license to use one copy of DOSLFNBK indefinitely. If you include an email address when you register I will notify you of new versions and how to obtain them yourself. I'll also attempt to answer emailed questions about DOSLFNBK from registered users.
DISCONTINUED $20 bonus program registration
DISCONTINUED $45 source code registration

Volume discounts, site licenses and custom versions are available as described here.

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Last updated 21 October 2004