Jan 022018
 
Recover hard disk from an accidental or unwanted reformat; protect against Trojan programs, too.
File UNFORMAT.ZIP from The Programmer’s Corner in
Category Utilities for DOS and Windows Machines
Recover hard disk from an accidental or unwanted reformat; protect against Trojan programs, too.
File Name File Size Zip Size Zip Type
UNFORMA-.COM 20334 13006 deflated
UNFORMAT.COM 13988 13988 stored
UNFORMAT.DOC 7015 2582 deflated

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Contents of the UNFORMAT.DOC file



Un Format -- Accidental Hard Disk Format Protector

Un Format does what seems impossible. It, when used correctly,
actually recovers a hard disk from an accidental format. Un Format
protects you from a hard disk format, but it also protects you from
Trojan Horse programs that modify your hard disk's FAT or root
directory. Un Format makes these programs and accidental formats
harmless.

Now, by using Un Format, you can breathe easier and not be afraid of
losing everything on your hard disk accidentally.

The complete invocation for Un Format from the DOS prompt is:

UF /SAVE or /RESTORE d: []

/SAVE Save the disk. The /SAVE option saves the drive d: in
the default of specified filename.

/RESTORE Restore. The /R option restores drive d: from the
filename specified (or the default filename).

Note: either /SAVE or /RESTORE must be specified. If neither are
specified, Un Format won't run.

d: The drive to save/restore. In most instances, this is C:, but it
doesn't have to be. Any valid drive is accepted, however, Un Format
works correctly only with hard disk drives.

The name of the file to "save" drive d: in. This parameter
is optional. If you don't specify a filename, Un Format
will use the default filename of B:UnFormat.10a.

Before using Un Format, you should copy UF.COM on a blank, formatted
diskette, and use this disk as your Un Format disk.

Although Un Format has gone through extensive testing to make sure it
works in all situations, please test it on your system before relying
on it.

To test Un Format, follow these instructions or perform a similar
sequence of events.

1. Backup your entire hard disk so that it can be restored
after formatting if Un Format cannot restore it.

2. Save the hard disk on your Un Format disk.

3. Using CHKDSK, see what the hard disk looks like.

4. Format the hard disk.

5. Restore the hard disk using Un Format.

6. Using CHKDSK, see what the hard disk looks like. It
should be the same as before the format.


What was typed if you followed these instructions should look something
like this:

backup
UF /SAVE c:
chkdsk c:
format c:
UF /RESTORE c:
chkdsk c:

In order for Un Format to be useful, it has to be used regularly. If
it isn't used often or in an organized method, it won't be of any use at
all.

I recommend two methods for using Un Format on a regular basis.

The first method is to run Un Format from your AUTOEXEC.BAT file. By
doing this, you will at least always have recently saved the hard disk.
To run Un Format in the AUTOEXEC.BAT file, make sure that a formatted disk
is available in drive B: when your computer starts up. Insert the
following line in your AUTOEXEC.BAT file:

UF /SAVE c:

The next method is to create a .BAT file that will run Un Format before
formatting your hard disk. This lets you restore the hard disk even when
you did intend to format it. Rename FORMAT.COM to NEWFORMA.COM and
create the file FORMAT.BAT as shown below.

echo off
if "%1" == "" goto UnFormat
if "%1" == "C:" goto UnFormat
if "%1" == "c:" goto UnFormat
goto formatt
:UnFormat
echo Insert the Un Format diskette in drive B:
Pause
UF /SAVE c:
:formatt
newforma %1

By using either of these two methods, you should be protected from
any accidental format of your hard disk.

Un Format can also be used to safeguard against programs that may alter
the FAT or root directory. These programs could be Trojan Horse programs,
or they might be your own programs. I use Un Format when trying out new
features for Master Key.

If an accidental format does happen, put your Un Format diskette in a
floppy drive and restore the hard disk by typing:

UF /RESTORE c:

After Un Format completes, your hard disk should be restored to look like it
before it was formatted.

"How can you Un Format a hard disk? Isn't that impossible?"

No, restoring a hard disk after formatting it is not totally impossible.

When a hard disk is formatted using all versions of DOS up to and
including DOS 3.10, the FORMAT command does not really write over
everything on the disk, it just gives that impression. The FORMAT command
performs a soft format of the hard disk. A soft format basically means
that the structure of the disk isn't modified, just rechecked. FORMAT,
when run, checks the hard disk for bad sectors and then clears and rewrites
the hard disk's FAT and root directory.

Un Format is able to protect against an accidental hard disk format by
writing all of the disk information, FAT information, and root directory
in the file name specified.

"Can it protect against all kinds of formatting?"

Un Format unfortunately can only protect a hard disk against a format done
by the FORMAT command or other programs that perform soft formatting
of the hard disk.

There are other programs that perform hard formatting of the hard disk.
These programs actually change the structure of the hard disk, and
thus cannot be protected by Un Format. Fortunately, the formatting
programs that Un Format cannot protect against typically do not
automatically format your hard disk. It is very unlikely that you could
accidentally format your disk with one of these programs.

"So, why can't you Un Format a floppy disk?"

Un Format runs just as well if the disk it thinks it is saving is a
floppy disk. The difference is that you won't gain anything by restoring
a floppy disk. This is because FORMAT, when formatting a floppy disk,
actually rewrites all of the sectors on the disk with a given fill
character. If you restore a floppy disk using Un Format, the disk may
appear to be fine, but all of the files lose all of their data and will be
useless.

"What if the file my hard disk is saved in gets changed?"

Before Un Format does any restoration of a hard disk, it goes through
many exhaustive checks to make sure everything is absolutely ok. First,
it checks to make sure that the disk you are restoring and the disk that was
saved are the same. Then, Un Format checks to see if the file the disk
was saved in has changed in any way. If anything at all is different,
Un Format will not make any changes to the hard disk. It is nearly impos-
sible for a corrupted or maliciously altered file to be restored on a hard
disk.

-end-


 January 2, 2018  Add comments

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