do old floppy diskettes work the same like hdds regarding erasing old deleted files, or free space using softwares filling that space with random data, or it is a different matter?
How many passes would be needed to erase an old floppy diskette beyond recovery?
1
Microwaves and fires are good too. Big magnets. Scissors. Pretty easy to distroy
HOW many passes !!!!
ONE for FLOPPY
ONE for HDD
mitch
But, but, but…what about the guy in the basement of the NSA with an electron microscope?
roll
But, but, but…what about the guy in the basement of the NSA with an electron microscope?
roll
During the few days I am Reading about this subject I have already read about "electron microscopes" used by high scientists. Stories that I had not believed in, some weeks ago…
However, just out of curiosity…When we are speaking of these high forensic levels…an electron microscope can read from a wiped (or broken) device only meaningless groups of 0s and 1s or really full texts, phone numbers, addresses, etc?
I was joking. One pass is enough.
When hard drive capacities were small and there was significant space between tracks on the platter, it was technically possible to recover some bits with an electron microscope because data would be written between tracks occassionally as the platter expanded and contracted as it heated and cooled. With modern drive, this is no longer possible, and I would argue it's never been feasible. You would be reading just the 1s and 0s. The chance of recovering anything useful would be very small.
For instance, just the first line of this post in binary is0100100100100000011101110110000101110011001000000110101001101111011010110110
1001011011100110011100101110001000000010000001001111011011100110010100100000
0111000001100001011100110111001100100000011010010111001100100000011001010110
11100110111101110101011001110110100000101110
Even a floppy disk has about 16 million 1s and 0s to sift through. Try reading those one at a time manually and trying to make sense of any of it.
When hard drive capacities were small and there was significant space between tracks on the platter, it was technically possible to recover some bits with an electron microscope ….
Though there is not one single report of anyone having ever recovered anything through an "electron microscope" (or through a magnetic force microscope).
It has been speculated that it would have been possible, yes, it has been said that the guy in the basement of NSA made it, but actually noone ever published anything meaningful.
It's like Keyser Soze
http//
… a myth, a spook story that digital forensicators and data recovery people tell their kids at night.
Of course wink 
jaclaz
I would be slightly concerned about erasing a 48tpi disk with a 96 tpi drive. Is was never recommended, and often caused errors.
Otherwise, in the real world, 1 pass is fine
This comes up regularly and on a few occasions I have said that on modern drives it is nigh on impossible to read data (at least with the facilities that we have) On older hard drives and especially floppies it was doable (and I did it).
Simply put floppies and older hard drives user stepper motors to step between tracks and had no embedded servo which meant that track 23 today would not be written exactly where track 23 was written yesterday. On a floppy that was written initially on one drive and then moved to a second drive the situation was exacerbated. It was sometimes possible to read down the side of a track and verify that the data that you read was good by means of the ECC (or CRC on a floppy).