Deleted files on Floppy & Hard disk -remnants ?

Deleted files on Floppy & Hard disk -remnants ?
=================================

1) When you delete a file from a Floppy disk
-what information is left about that file ??

I know that the data may remain for the file, unless it is wiped or
overwritten ?

What about the Fille name, does information on that still exist ??
-about when it was created on the Floppy disk ??
-when it was deleted ??

Is this the same for a Hard Disk ??

2) How do you delete all information about a particular file, when the file
it is deleted ??

3) Does Disk Copy of a Floppy Disk do an exact copy ??

-does it only copy Files that exist ??
-does it also copy deleted data ??
-is the copy an exact mirror image ??

4) What information goes onto a Floppy, when it first formatted ??
-is there any information about the computer ??
-is there any information about the operating system ??
-does it datestamp the floppy when it is formatted ??

Thanks

When you simply delete a file from DOS or Windows one character of the
filename entry in the directory is changed. All other information remains
until it is overwritten. I don't believe that date deleted is recorded, but
you can easily test this. The process is the same for hard disks and for
floppies.

There are many disk wiping functions available. They write data into all
unused portions of the disk, overwriting any data left behind from deleted
files. The advanced utilities also rewrite directory entries, removing
references to the filename. If you google on file wiping utilities you
should find plenty of examples.

DiskCopy is a byte-for-byte copy, so everything, including deleted files is
copied. It is an exact image, not a mirror image.

The information written to a floppy when it is formatted depends on the
formatting options and whether the floppy is already formatted. For
instance, if it's already formatted it is possible to retain unformatting
data on the floppy. If it's a quick format the data area is not erased. OS
or machine information is not written to the floppy. It is not datestamped
(although I believe the date and time is part of the disk ID that formatting
creates). Note that anyone can write their own floppy disk format utility,
and it could include a large number of possible features such as you have
described.
--
Jeff Richards
MS MVP (DTS)
"============ ABC ============" wrote in message
...
Deleted files on Floppy & Hard disk -remnants ?
=================================

1) When you delete a file from a Floppy disk
-what information is left about that file ??

I know that the data may remain for the file, unless it is wiped or
overwritten ?

What about the Fille name, does information on that still exist ??
-about when it was created on the Floppy disk ??
-when it was deleted ??

Is this the same for a Hard Disk ??

2) How do you delete all information about a particular file, when the
file
it is deleted ??

3) Does Disk Copy of a Floppy Disk do an exact copy ??

-does it only copy Files that exist ??
-does it also copy deleted data ??
-is the copy an exact mirror image ??

4) What information goes onto a Floppy, when it first formatted ??
-is there any information about the computer ??
-is there any information about the operating system ??
-does it datestamp the floppy when it is formatted ??

Thanks

"============ ABC ============" wrote in message
...
Deleted files on Floppy & Hard disk -remnants ?
=================================

1) When you delete a file from a Floppy disk
-what information is left about that file ??

I know that the data may remain for the file, unless it is wiped or
overwritten ?

What about the Fille name, does information on that still exist ??
-about when it was created on the Floppy disk ??
-when it was deleted ??

Is this the same for a Hard Disk ??

File deletion is the same on Hard and Floppy Disks.
The File Allocation Table assigns (multiples of) 32
bytes to each file showing in the first 11 places its
DOS filename and filetype, then in the remaining
bytes those file sectors it occupies (coded in hex).
It looks like this:
FILENAMETYPxyzxy
xyzxyz0000000000

Deleting a file simply overwrites the first char with e
thus
eILENAMETYPxyzxy
so the FAT ignores the following sector assignments
xyz etc.
i.e. treats those sectors as free for the next Write
File command.

DOS UNDELete programmes simply present the
FAT eILENAMETYPxyzxy
and allow you to change the first byte to non-e
FILENAMETYPxyzxy
which restores the file entry to the FAT, and also
all its sector assignments. (If they have been
overwritten in the mean time this causes cross-linked
files, which SCANDISK and CHKDSK are set up
to repair.)

2) How do you delete all information about a particular file, when the
file
it is deleted ??

This can be done only by overwriting the 32 (or 64 or 96)
bytes in FAT showing the original entry and all the sectors
the file occupied. FORMAT is the simplest way to do this.

3) Does Disk Copy of a Floppy Disk do an exact copy ??

-does it only copy Files that exist ??
-does it also copy deleted data ??
-is the copy an exact mirror image ??

Good DOS DISKCOPY routines did this, i.e. copied
the whole of a disk, sector by sector, including its FAT.

4) What information goes onto a Floppy, when it first formatted ??

FAT space, bootable system code space, and space available for files.

-is there any information about the computer ??
-is there any information about the operating system ??

No and No

-does it datestamp the floppy when it is formatted ??

Yes by default under Windows, if you decline to give it a
disk name.

--
Don Phillipson
Carlsbad Springs
(Ottawa, Canada)

The information you have described is not stored in the FAT. The FAT only
maintains a record of which disk sectors are used and which are not used.
The information about files is stored in a directory entry.
--
Jeff Richards
MS MVP (DTS)
"Don Phillipson" wrote in message
...

"============ ABC ============" wrote in message
...
Deleted files on Floppy & Hard disk -remnants ?
=================================

1) When you delete a file from a Floppy disk
-what information is left about that file ??

I know that the data may remain for the file, unless it is wiped or
overwritten ?

What about the Fille name, does information on that still exist ??
-about when it was created on the Floppy disk ??
-when it was deleted ??

Is this the same for a Hard Disk ??

File deletion is the same on Hard and Floppy Disks.
The File Allocation Table assigns (multiples of) 32
bytes to each file showing in the first 11 places its
DOS filename and filetype, then in the remaining
bytes those file sectors it occupies (coded in hex).
It looks like this:
FILENAMETYPxyzxy
xyzxyz0000000000

Deleting a file simply overwrites the first char with e
thus
eILENAMETYPxyzxy
so the FAT ignores the following sector assignments
xyz etc.
i.e. treats those sectors as free for the next Write
File command.

DOS UNDELete programmes simply present the
FAT eILENAMETYPxyzxy
and allow you to change the first byte to non-e
FILENAMETYPxyzxy
which restores the file entry to the FAT, and also
all its sector assignments. (If they have been
overwritten in the mean time this causes cross-linked
files, which SCANDISK and CHKDSK are set up
to repair.)

2) How do you delete all information about a particular file, when the
file
it is deleted ??

This can be done only by overwriting the 32 (or 64 or 96)
bytes in FAT showing the original entry and all the sectors
the file occupied. FORMAT is the simplest way to do this.

3) Does Disk Copy of a Floppy Disk do an exact copy ??

-does it only copy Files that exist ??
-does it also copy deleted data ??
-is the copy an exact mirror image ??

Good DOS DISKCOPY routines did this, i.e. copied
the whole of a disk, sector by sector, including its FAT.

4) What information goes onto a Floppy, when it first formatted ??

FAT space, bootable system code space, and space available for files.

-is there any information about the computer ??
-is there any information about the operating system ??

No and No

-does it datestamp the floppy when it is formatted ??

Yes by default under Windows, if you decline to give it a
disk name.

--
Don Phillipson
Carlsbad Springs
(Ottawa, Canada)