Recover Fixed/Floppy Disk - FAQ

Program Specific Experiments

MANUALLY RECOVERING A FILE
USING DEBUG TO EXPLORE BOOT, FAT, DIRECTORY SECTORS ON FLOPPY DISKS
RECOVERING FILES AFTER DELIBERATELY ERASING DIR ENTRIES

Program Specific Experiments

Experiment 1

MANUALLY RECOVERING A FILE

SOME QUERIES FIRST:

What are these numbers under column 2 (the one after the File Name column)?

I don't understand the hexadecimal numbers under the column 1st LSector?

What can I do with the hex numbers displayed under the column heading 1st Logical Sector?

I have only the RECOVRFD.RPT file for a subdirectory on a floppy. Can I do something to get a few of my files?. If yes, can you give me some tips?

These hexadecimal numbers are so important that they bring your files close to your heart.

These hex numbers (under column 2) represent the starting sector numbers of the actual contents of files or directories as the case may be.

LET US DO AN EXPERIMENT

You can access files by using DEBUG.EXE. Run DEBUG.EXE and run the Load command. The Load command syntax is as follows.

Load [address] [drive] [firstsector] [number]

address is where in memory you want the file contents to be written.

drive is the zero-based drive number. 0 represents the A drive; 1 = B; 2 = C; and so on.

firstsector is the hex number you see under column 1st LSector for the particular file you want to recover manually.

number is the number of sectors you want DEBUG to read from the floppy / hard disk.

Suppose that you want to get the special AUTOEXEC.BAT from drive A:. Assume further that the details for this file are as follows (as reported in RECOVRFD.RPT):

File Name             1st LSector  FAT Sector  #Clusters   #Fragments

AUTOEXEC.BAT     -         21           3           2            1

Now you have drive=0;firstsector=21;number=2 (i.e. number of sectors). And address=100 or as you wish.

firstsector is available from column "1st LSector". Number of sectors is available from column "#Clusters". In the case of 1.2 MB and 1.44 MB floppies, 1 Cluster = 1 Sector.

Remember that DEBUG always expects numbers in hex. And, for your convenience, the numbers available from RECOVRFD.RPT are also in hex.

Now at DEBUG's - prompt type something like the following (without the hyphen) and hit enter:

-L100 0 21 2

Now you can dump what DEBUG has read. Just type the following command (without the hyphen) and hit enter:

--D100

Now you can see AUTOEXEC.BAT's contents right here in memory from address somesegment : 0100

Now you can ask DEBUG to write this into a file named AUTOEXEC.BAT in C:\TEMP. To do this just type the following commands (without the hyphens and without the comment at the right) at DEBUG's prompt:


-NC:\TEMP\AUTOEXEC.BAT		Name filee as AUTOEXEC.BAT and save in C:

-RCX				Receive file size

CX 0000				Displayed by DEBUG; not typed by you. 

:400				i.e. 2 (#Clusters) * 512 = 1024 bytes = 400h )

-W100				Write from address 100h

Writing 00400 bytes			Disp. by DEBUG. 400h = 100h * 4 = 256 bytes * 4 = 1024 bytes

-Q				Quit (i.e. exit DEBUG)

Now you have recovered your special AUTOEXEC.BAT and saved it in C:\TEMP.

To remove junk at the tail end of file, open it in an editor, remove the junk and save it.

Experiment 2

USING DEBUG TO EXPLORE BOOT, FAT, DIRECTORY SECTORS ON FLOPPY DISKS

Remember DEBUG's command syntax is this:
Load [address] [drive] [firstsector] [number]

Warning!

Don't change to another floppy while working on one inside DEBUG unless you precisely know what you are doing.

TO READ BOOT CODE

Run the following command at DEBUG's hyphen prompt. Drive zero = Drive A:

-L100  0  0  1

TO READ FAT COPY 1 ON A 1.2 MB FLOPPY DISK

Run the following command at DEBUG's hyphen prompt. Drive zero = Drive A:
(Recover Fixed/Floppy Disk shows the readability of 7 sectors from 1 thru 7 [FAT Copy 1] for a 1.2 MB floppy).

-L100  0  1  7

TO READ FAT COPY 2 ON A 1.2 MB FLOPPY DISK

Run the following command at DEBUG's hyphen prompt. Drive zero = Drive A:
(Recover Fixed/Floppy Disk shows the readability of 7 sectors from 8 thru 0Eh [FAT Copy 2] as well for a 1.2 MB floppy).

-L100  0  8  7

TO READ FAT COPY 1 ON A 1.44 MB FLOPPY DISK

Run the following command at DEBUG's hyphen prompt. Drive zero = Drive A:
(Recover Fixed/Floppy Disk shows the readability of 9 sectors from 1 thru 9 [FAT Copy 1] for a 1.44 MB floppy).

-L100  0  1  9

TO READ FAT COPY 2 ON A 1.44 MB FLOPPY DISK

Run the following command at DEBUG's hyphen prompt. Drive zero = Drive A:
(Recover Fixed/Floppy Disk shows the readability of 9 sectors from 0Ah thru 12h [FAT Copy 2] as well for a 1.44 MB floppy).

-L100  0  A  9

TO READ ROOT DIRECTORY (14 SECTORS) ON A 1.2 MB FLOPPY DISK

Run the following command at DEBUG's hyphen prompt. Drive zero = Drive A:

-L100  0  F  E

TO READ ROOT DIRECTORY (14 SECTORS) ON A 1.44 MB FLOPPY DISK

Run the following command at DEBUG's hyphen prompt. Drive zero = Drive A:

-L100  0  13  E

TO READ FIRST DATA SECTOR ON A 1.2 MB FLOPPY DISK

Run the following command at DEBUG's hyphen prompt. Drive zero = Drive A:

-L100  0  1D  1

TO READ FIRST DATA SECTOR ON A 1.44 MB FLOPPY DISK

Run the following command at DEBUG's hyphen prompt. Drive zero = Drive A:

-L100  0  21  1

TO SEE WHAT DEBUG HAS READ

Run the following command at DEBUG's hyphen prompt:
(You may run this DUMP command after each LOAD command stated above).

-D
or
-D100

Experiment 3

RECOVERING FILES AFTER DELIBERATELY ERASING DIR ENTRIES

1. Get a scratch disk. A fresh floppy is recommended if you are in a hurry.
2. Create a single subdirectory in the root directory and CD to the created subdir.
3. Copy some files into it.
4. Run Recover Fixed/Floppy Disk v1.4 to see if each of the files you just copied into the subdir are contained in one fragment (i.e. one chunk). Otherwise, defrag the disk. If the disk has some errors, the defragmenter won't be able to do its job. If it was the only disk you can find, just delete the files with 2 or more fragments. (But don't delete any file for any reason when actually recovering files from a damaged disk).
5. If too many files have more than one fragment, create another subdirectory in the root dir. And repeat from step 3 above.
6. Run Recover Fixed/Floppy Disk v1.4 on the root dir and note down the 1st LSector (starting sector) for the recently created subdirectory possibly with files in single fragments.
7. Run Recover Fixed/Floppy Disk v1.4 and save that particular subdirectory's structure in a file. To do that just run the following command:

RECOVRFD A:\GETME C:\TEMP -D -X <ENTER>

Here GETME is the subdir's name. Substitute GETME with your subdir's name. This is the subdir you are going to save or backup. C:\TEMP is the destination drive and path that receives the file.
8. Run DEBUG. From now on you have to be very careful. If you are an expert, you may skip the rest and jump to step 9 below. For, a single change in a single number on a WRITE command could corrupt a good disk. So be very careful with all the WRITE commands. If you are tense or in a hurry or have been concentrating on some other others-can't-do-it kind of stuff, please take some rest or a nap or just start all over again tomorrow morning before doing anything else and have a great time.
9. Type the following command at DEBUG's hyphen (-) prompt. Here 0 is drive 0, that is, drive A:. 0AC1h is the 1st LSector for the GETME subdir on our 1.44 MB floppy. 1 is the number of sectors to read.

Substitute AC1 with the 1st LSector number you got for your subdirectory.

-L100   0  &nbssp;AC1   1   <ENTER>

After DEBUG reads the specified sector, run the following command to dump memory offset 100h:

-D100   <ENTER>
>
This command only DUMPs 128 bytes. To see all (512 bytes), proceed with more D's (3 of them) like:

-D   <ENTER>
-D   <ENTER>
-D   <ENTER>
Now you have seen what the subdirectory you passed to RECOVRFD.COM contains.

Now you are going to erase these dir entries. Run the following command to fill the first 512 bytes at memory offset 100h with 0's:

-F100   2FF  &nnbsp;0    <ENTER>

Now write it to disk in drive A:.

Be very careful. Don't change the drive number which is 0. You must not have changed disk in between. And remember to substitute AC1 with your subdir's 1st LSector.

-W100   0  &nbssp;AC1   1 <ENTER>

Now DEBUG writes 0's right upon the directory entries (i.e. sector AC1 on our disk) and erases them.

Exit from DEBUG by typing

-Q   <ENTER>
Now run the following command to get the files whose directory entries you just erased:

RECOVRFD   A:   C:\TEMP   -LC:\TEMP\GETME   -X    <ENTER>
10. If you want to get the erased subdirectory structure back on its place (on our disk: sector AC1) by using the backup, run the following commands (remember AC1 is not AC1 in your case):

DEBUG C:\TEMP\GETME <ENTER>
-W100 0 &nbssp;AC1 1 <ENTER>
-Q <ENTER>

Program Specific Questions

When can I get that version of Recover Fixed/Floppy Disk with the capability to "ignore the corrupt/unreadable/zeroed-out FAT copies", the "-I switch"?

The "Ignore FATs" switch, the superpower switch -I, has been one of the big features from version 2.0 of Recover Fixed/Floppy Disk. We hope it will be useful to those who have to recover files from accidentally reformatted disks. Currently Recover Fixed/Floppy Disk v2.2 is available at $15 (US Dollars).

Can any future version of Recover Fixed/Floppy Disk handle the following: bad sector(s) in directory (root dir or any other) which stops WINDOWS 98 from listing anything when a DIR command is issued?

Recover Fixed/Floppy Disk v2.2 provides a two-step solution to handle hole-in-a-directory conditions. It is as simple as saving that directory to a file (DirEntriesFile) and recovering files by passing this DirEntriesFile to Recover Fixed/Floppy Disk in the next invocation. One of the aims of Recover Fixed/Floppy Disk is to make seemingly complex situations easily manageable. The two-step process lets you recover all the files excluding those whose entries are trapped in bad sectors. It is of course a big problem if what was so trapped was a subdirectory. Manually finding the subdirectory and saving its contents to a file for passing it to Recover Fixed/Floppy Disk to recover the files is the only solution. Of course it is difficult to find the exact subdirectory unless names of some files kept in it could be remembered and what is more, everyone may not have a disk utility to view sectors after sectors. A big solution could be a program to automatically find all subdirectories and save them as files for use by Recover Fixed/Floppy Disk. This situation clearly indicates that it should be so arranged that a backup must not have subdirectories at all so as to avoid the subdirectory-trapped situation. An entire directory structure with files (with any number and level of subdirectories) backed up as a ZIP ( or any ) archive seems to be a solution that can handle even sabotage conditions.

Recover Fixed/Floppy Disk runs just in the assumption that file contents can be found in contiguous sectors. Can't things be rooted in better theories?

If you regularly defrag your drives, then "file contents can be found in contiguous sectors" is as much a reality as your personal computer's capabilities.

Contiguous files are just a reflection of your high-tech lifestyle. If you have adopted that lifestyle, you are served better than others.

Recover Fixed/Floppy Disk is invaluable to those who have adopted to the lifestyle of regularly defragmenting their disk drives to safeguard their data. The first step in that direction is defragmenting disk drives - a better defragmenter leaves slack space at the end of each file that will ensure that files don't fragment for sometime, say, until you remember to run the defragmenter the next time. (One must not use just any defragmenter in "power-may-go-off-at-any-time" environments).

We want everyone in the File Allocation Table world to know that Recover Fixed/Floppy Disk reduces the complexity of recovering data from the data recovery firm level to individually manageable level.

What can be done just with a single directory and saving its structure in a file?

Imagination is the limit. With archiving programs, one can roll up an entire drive into a file (say, a ZIP archive, or if you need RAR's capabilities in correcting corrupt data, an RAR archive) and keep the file in a separate partition. Now how many files one can put in a directory can be a relevant question.

Can I know when recovery is Halted exactly?

Whether or not a file's contents are contiguous, if the disk has suffered physical damage in a data sector belonging to that file, reading of that sector would fail (because of surface damage). In such cases, the attempt to recover that file would be halted. Hence the remark Halted. Whatever has already been recovered can be found in the partially recovered file. With the file's first sector available from the report (.RPT) file, one can try to access the file manually.

What is the aim of Recover Fixed/Floppy Disk?

I just don't understand the program. What is the big thing about it?

RECOVER Fixed/Floppy Disk foresees a situation where backed-up FAT and Directories could not be restored because of surface damage. So this program is required even by the precautious people who already backup their FAT's and Directories. When the disk was defragmented light years back and unfortunately the backed-up FAT's / Directories could not be restored because of surface damage to disk .... That is why we so much insist on defragmenting your HDD's and Floppies.

A top class Backup and Restore program that can save and restore critical system areas on disks may seem like an all-in-one solution but what one can do if it cannot Restore the things to the disk sectors where it got them, because of surface damage to disk. Just give the backed-up directory to RECOVER Fixed/Floppy Disk with switch -L (which makes the program look for file and directory entries in the file supplied rather than on the disk), and get back your files.

By the way, there are situations, even in the case of floppy disks (consider their cost), where no one on earth can help. Recover Fixed/Floppy Disk tries to remove from this planet these "entire world can't help me" kind of situations. The program just asks you to take a few precautions. You will learn in 5 months what others took 5 years to learn. The program is a good starting point to learn the FAT file system. For a start, try to copy USER.DAT and SYSTEM.DAT to some other location from a DOS box while inside Windows. A1 Yippee Shareware conferred a 4-star rating to Recover Fixed/Floppy Disk v1.2a and a 5-star rating to its documentation.

If the boot sector on my floppy becomes bad, what can I do?

The solution is simple. Just get Recover Fixed/Floppy Disk v2.2. It has a special switch to supply Boot Record thereby making DOS to work on the floppy as good as on a good one with a good Boot sector.

General Questions

Where is the boot sector located?

It is sector 1 on track 0, side 0 near the outer edge of a floppy disk.

Where are File Allocation Tables located?

On floppy disks, the first FAT (File Allocation Table) immediately follows the boot sector. The second FAT follows the first. For example, on a 1.2 MB floppy, FAT copy 1 occupies sectors 2 thru 8 and FAT copy 2 occupies sectors 9 thru 15 both on track 0, side 0.

Where is the root directory located?

The root directory is located after the FAT copies. For instance, on a 1.2 MB floppy it starts with sector 1 on track 0, side 1; on a 1.44 MB floppy it starts with sector 2 on track 0, side 1.

What are Head, Track, Cluster and Sector briefly?

Head - Read/write head
Track - A sub-unit of disk surface
Sector - A sub-unit of a Track
Cluster - One Sector or a bunch of Sectors

What are Tracks?

A track is a circular area of the disk surface. Tracks are circular pathways that end in themselves. Hence the alternate name Cylinders. The read/write heads of the disk drive ski in the air to get to the next sector or track. Tracks are numbered from 0. Track 0 is the first track.

What are Sectors?

A sector is a small part of a track. A track gets divided in to a number of sectors. 15 sectors fit into a track on a 1.2 MB floppy. One sector of disk surface usually accommodates 512 bytes. Sectors are numbered from 1.

What are Heads or Sides?

Heads or Sides are either the actual number of read/write heads (one disk surface [Side] needs one head) or simulated read/write heads (sides) in the case of large disks. The words head and side are used interchangeably. Heads (sides) are numbered from 0. That is, the first head is head 0.

Can you list the starting sectors for Boot, FAT 1, FAT 2, Root Dir, and Data?

The following table lists the Logical Starting Sector numbers for system and data areas for floppies that will be useful when running DEBUG.EXE. All numbers (excl. column 1) are in hex.

Disk Type	FAT 1	FAT 2	Root Dir	Data
360 KB	1	3	5	0Ch
720 KB	1	4	7	0Eh
1.2 MB	1	8	0Fh	1Dh
1.44 MB	1	0Ah	13h	21h

What about FAT32?

On a FAT32 File System to avoid fragmentation of directories without ever having to defrag the drive, no directory should hold more than 128 (8 sectors * 16 entries per sector) files / dirs. If the entries are long file name entries, it falls to 64 entries at the maximum.

On a FAT16 File System to avoid fragmentation of directories again without ever having to defrag the drive, no directory, for instance on a 2 GB drive, should hold more than 1024 (64 sectors * 16 entries per sector) files / dirs. Even if there are only long file name entries, one can hardly fill up one (the first one) cluster of directory space under normal usage conditions. This ensures that directories never get fragmented. To that extent defragmentation would take lesser time. Files also get 64 sectors in each cluster allocated to them. Sectors in a cluster are always contiguous. The more the number of sectors in a cluster (allocation unit), the lesser the files get fragmented. And the defragmenter gets to do a smaller job and completes faster. The lesser the defragmenter takes to defrag a drive, the more the user will use it to get his files and dirs defragmented. The lesser the files are fragmented, the higher the safety and availability of files / dirs. One can think of 100 percent recovery of files from an accidentally reformatted drive which had all the files and dirs defragmented. Just get RECOVER Fixed/Floppy Disk v2.2 which is available now. FAT16 File System is a blessing in disguise for so many of us from programmers to those who never defrag. On a FAT16 File System files don't get fragmented every now and then and directories never get fragmented under normal usage conditions. Defragmentation is faster.

If one can think that disk space usage optimization is more important than optimization of safety and availability of data, sometimes source code, he/she is really having a great time enjoying life at its best. Programmers really envy that.

List the difference between RECOVER Fixed/Floppy Disk Version 2.2 and Version 1.4.

Difference between v2.2 and v1.4 of RECOVER Fixed/Floppy Disk:

Sl No	RECOVER Fixed/Floppy Disk v2.2	RECOVER Fixed/Floppy Disk V1.4
1	Can recover files from accidentally reformatted disk if Root Folder (Root Directory) or any subfolder (subdirectory) has been backed up and is available as a file. A Root Folder extracted from any backup in its raw format can be used to recover files.	Cannot recover files after accidental reformat.
2	If free disk space is available, user can use version 3.0 or 2.2 to train himself on recovering files by creating a new disk partition and copying files to it and then deliberately reformatting it after backing up the Root Folder (Root Directory), without waiting for an accidental reformat to occur. This way one can also figure out how to keep files and folders (directories) in order. If free space on HDD is not available, a floppy will suffice. Get a scratch floppy disk, copy some files to it, backup Root Folder, deliberately reformat the disk and recover files starting with the Root Folder by using its backup and the experience you get is priceless.	No such self training is possible as version 1.4 cannot recover files from reformatted disk.
3	FAT can be ignored by specifying switch -I. This switch is an absolute necessity when FAT copies had been erased (for example, in an accidental reformat) or had become corrupt completely.	FAT cannot be ignored by specifying a switch.
4	Root Folder (Root Directory) or subfolder (subdirectory) can be recovered / backed up as a file. Program can recover Root Folder (Root Directory) and save it to a file with a default name (when a command line switch is specified) even if FAT has been rendered useless.	Only subfolder (subdirectory) can be recovered / backed up as a file.
5	Subfolder (Subdirectory) can be recovered as a file without using information in File Allocation Table (for example, when some FAT sectors were physically damaged).	Subfolder (Subdirectory) cannot be backed up as a file without using information in File Allocation Table.
6	Root Folder (Root Directory) or subfolder (subdirectory) that is recovered / backed up as a file has a header. Any folder (directory) finder can find the contents of this file and interpret it as a folder (directory) despite the header at the top when this file cannot be accessed in the normal way as when this file gets locked up in the reformatted disk.	Subfolder (Subdirectory) that is recovered / backed up as a file has no header. But it can be found by any folder (directory) finder.
7	Boot sector can be supplied by specifying a switch for boot sector damaged floppies of type 360 KB, 720 KB, 1.2 MB and 1.44 MB. The floppy need not have been defragmented unless FAT too got damaged.	Boot sector cannot be supplied to recover files from a boot sector damaged floppy.
8	FAT usage can be optimized by specifying a supplementary FAT copy for use if primary FAT copy has bad sectors. That is, both FAT copies can be used by program in an optimized way when both FAT switches are specified on command line. Of the two FAT copies present in a FAT file system, any one FAT copy can be used as primary FAT copy and the other one as supplementary FAT copy through command line switches. These switches are useful when both FAT copies have a few bad sectors and if supplementary FAT copy can supply data for damaged FAT sectors in the primary FAT copy. (The OS always considers a FAT copy as that and not as primary or supplementary).	Only one FAT copy can be used at any time for recovering files / folders.
9	Two types of report files are generated. A Facts Report file when switch -O is specified (without switch -R or -X accompanying) and a Recovery Report file when switch -R or -X is specified.	Only one type of report file is generated. Unlike it is in the commercial version the report file obtained by specifying switch -O (without switch -R or -X accompanying) will not contain extraordinary file / folder location details.
10	A new report file which is highly recommended to be obtained before any disk errors occur is named like RFD_?.RPT (? = A or B or C and so on) which is the Facts Report file and is extremely useful as it contains extraordinary details of location of file / folder content (including for fragmented files / folders).	The report file is always named RECOVRFD.RPT and it never contains location details for all fragmented (file / folder) content.
11	If Long File Name support is available, Long File Name format is used when recovering and saving files with long filenames.	Short File Name format is used when recovering and saving files even when Long File Name support is available. User has to rename files to LFN.
12	A Folders (Directories) only listing can be generated using switch -DO. And all lower level subfolders (subdirectories) in any specified parent folder can be recovered / backed up in a single run of program.	Switch -DO is not available.
13	Even folders (directories) with damaged FAT entry chain can be recovered if their contents are contiguous.	Folders (Directories) with damaged FAT entry chain are not recovered even if their contents are located in contiguous disk sectors.
14	An excellent program with anti-sabotage techniques. Must-have utility for environments where chances of disk reformat is very high.	Such techniques are restricted to subfolders only. They are not extended to Root Folder and File Allocation Tables.

Can you give me some tips and tricks?

Here are some tips and tricks to guard your data always.

Defragment each drive quite offen.
Always keep a copy of the Root Folder somewhere else.
Keep important files in the first level subfolders. Or just fit everything to your technology. As a general rule, never keep user created files or backup copies of them in folders whose paths are longer than 65 characters each. These folders could not be accessed by the OS when the system is booted through a WIN 95/98 BOOT DISK. This is the case when the system is booted/rebooted into "command prompt only" mode.
Never keep files in the Root Folder. Root Folder should have subfolders only.
Never reformat a disk giving switch -U unless it is absolutely necessary. And never introduce this switch of FORMAT.COM to new comers.

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