I've formatted hard drives since they were 2 megabyte on a double sided
12" hard disk. Have used a 36" vertically mounted hard disk that
creates a gyroscope effect when running. They - the 2Meg DEC and DG
disks required many pass testing and formatting to erase. Yet when
security was had, the disk was cut. The testing mapped bad blocks
using many patterns to improve testing.

I'm talking Secret to top secret grade company and military disks.

Security took the Military disks (they were formatted different from
civi types ) and Security (aka police) destroyed them their way.

They had fun - fire, rifle, pistol. Some just bent the disk.

So my 'silly example' is factual and you have a short experience
to say such.

Martin

On 1/26/2014 7:24 AM, Lloyd E. Sponenburgh wrote:
Martin Eastburn fired this volley in
:

Overwriting it won't always erase. We used to run 10 patterns to
quality a disk and afterwards we had to format the disk.

Low-level formatting will. Always. Martin, actually, that was a silly
example.

There's no reason why a drive with the defective media locations already
mapped would ever need formatting after a checkerboard test.

Perhaps the whole reason for your 10-pattern test was to identify the
defects, then to format with a new defect map.???

On some drives, rather than a stored defect map, defective sectors are
'jumped' over via a linkage table built right into the individual sector
headers. Those sorts MUST be formatted in a way to reflect the bad spots
on the medium.

LLoyd