news.txt

unformat格式化后的硬盘的数据恢复

News:


Version History:

Version 0.1     First version, unformats quick-formatted DOS 6.22 hard
		drives.  Program does not unformat floppy drives.

Version 0.2     Second version, unformats floppy disks; but, terminates
		with an error as it completes unformatting the floppy
		drive.  The floppy disk is completely and apparently
		successfully unformatted.

Version 0.3     Removed 2 unnecessary libraries under the "includes"
		section.  Temporarily fixed termination error when
		unformatting floppy disks.  I'll have to look for a
		better solution, though.

Version 0.4     Changed "cout" statements to "printf" statements for
		C compatibility.  As an added bonus, removing the
		"iostream.h" library for "cout" and using "stdio.h"
		for "printf" reduced the executable size by 15K.
		there still may be a problem with the "dos.h" library
		and C code compatability.  I also tested this program
		under Windows 95 in DOS mode with success.

		Note:  Before running program in Windows 95's DOS mode
		       type "lock" and when prompted, type "y" and [ENTER].

Version 0.5     Added /J function to verify the mirror image with the boot
		sector, the FAT tables, and the root directory.  Added a 
		message to let the user know that the unformat was 
		successful.  Removed the code that scans for the pointer
		to the mirror's location from the unformat function
		and made it a separate function to allow this function to be
		re-used by other parts of the program. 
		
		Discovered that this program really does not work with
		Windows 95.  Windows 95's format program does not write
		a mirror image to the disk.  When I originally was testing
		my program, the test drive was running under DOS 6.22.
		When I was testing the program, I quick-formatted the hard
		drive under DOS 6.22.  Then, I put the drive in a Windows 95
		machine and tested it again without wiping the drive.  So,
		the image was still there from DOS 6.22--oops!

		Found and fixed a bug in the unformatting loop for the FAT
		tables.  The counter was off by 1.

Version 0.6     Permanently fixed the problem unformatting the floppy drives
		as I mentioned in Version .3 and removed the temporary
		patch code.

		Added the /L function to list files and subdirectories in
		the root directory that were recovered.  (A quick format
		only removes root directory information, it does not affect
		the subdirectories themselves.)

		Changed the variable names for the 2 total number of sectors
		variables.

		Fixed the bug that prevented the unformatting of FAT12
		formatted hard disks.

		Found and fixed a bug that prevented the program from
		unformatting a drive with more than approx. 32767 sectors.

Version 0.7     Major modifications to the code:  Removed code that used
                interrupt 0x21 and replaced it with the code from the 
                format command that determines the drive location and
                uses interrupt 0x13 for drive access.  In consequence, the
                program now works with FreeDOS.

Version 0.8     Now supports up to 8 hard disks.

                Fixed a bug that prevented the program from accessing
                sectors above sector 1677216.

                Added the /PARTN function to restore partition tables
                saved with the "MIRROR /PARTN" command for FreeDOS.