[comp.sys.ibm.pc] What are bad diskettes?

jamesh@cs.umr.edu (James Hartley) (02/26/90)

There has been a rash of postings lately about buying cheap 5.25" and 3.5"
media, and several have mentioned MEI (800-634-3478) as being a good source.
I recently bought a lot of 25 diskettes, and only the first reported any
errors upon formatting.

QUESTION:  When this had happened to me before, I tried reformatting again.
With the MEI disk mentioned above, no errors were reported after the second
format.  I first discovered this a couple of years ago with three bad
Scotch branded 5.25" diskettes which reported fewer and fewer bad sectors
upon each subsequent format.  Can anyone explain to me what is happening?

--
James J. Hartley                 Internet:  jamesh@cs.umr.edu
Department of Computer Science     Bitnet:  jamesh@cs.umr.edu@umrvmb.bitnet
University of Missouri -- Rolla      UUCP:  ...!uunet!cs.umr.edu!jamesh

ted@helios.ucsc.edu (Ted Cantrall) (02/28/90)

In article <490@umrisca.usenet.umr.edu> jamesh@cs.umr.edu (James Hartley) writes:
>QUESTION:  When this had happened to me before, I tried reformatting again.
>With the MEI disk mentioned above, no errors were reported after the second
>format.  I first discovered this a couple of years ago with three bad
>Scotch branded 5.25" diskettes which reported fewer and fewer bad sectors
>upon each subsequent format.  Can anyone explain to me what is happening?
>
I can't explain for sure... I use to have great success in first BULK 
erasing all my floppies. It seems that a strongly imprinted magnetic
field can be hard for a Floppy disk head to completely over-write the
first time, but the bulk erase trick cleans it up nicely.	-ted-
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