Question about HD 1.44mb floppies on Amiga

[trydowave]

hi. Recently got hold of a lot of 1.44mb floppies for my Amiga500. Getting hold of the DSDD variety is incredibly hard these days. I've had no trouble with them yet, but ive read they become unreadble after a short amount of time?
Is this true?

My other questions:

1: Will they damage my drive?
2: Once they become unreadable can they be reformatted and written to again?

Thanks in advance
Tony

[demolition]

They will not damage the drive, but it can be hard for the drive to write data properly to them, since they have been IBM formatted. I have done it several times where it worked fine, but your milage may vary..

I read somewhere that if one could erase them completely with a bulk eraser, they should format fine to 880K format and work just as well as regular DSDD disks.

[Arnie]

I've used these disks before and had no problems with them. I always cover the extra hole with sticky tape.

Unless the disk has bad blocks or is physically damaged then I see no reason why they cannot be reformatted.

[trydowave]

thanx guys

[Cymru]

If the disks go in a standard A500 drive, then you don't need to do anything with the "hole." If you use a HD FDD, then do or don't cover the hole depending on how you want them formatted.

That IBM formatted & bulk eraser thing is not quite right and are two different subjects covered very well on several threads. CrossDos on the Amiga will format to MSDOS 1.44 or 720k (as CrossMac will try the 800/1.6); a PC FDD will format lots of different weird stuff but not Amiga nor Mac. The format does NOT determine the use as DD or HD. It is the physical magnetic media and the drive used (yes the dern controller matters too) that differs between a DD and HD floppy and the particle density and magnetic field used -- stuff I would know more about had I majored in physics and not chemistry. All of which is found in the forums.

[demolition]

Found this on Wikipedia which explains why you need a bulk eraser:

In IBM-compatible PCs, the three densities of 3 1⁄2-inch floppy disks are backwards-compatible: higher density drives can read, write and format lower density media. It is physically possible to format a disk at the wrong density, although the resulting disk will not work properly. Fresh disks manufactured as high density can theoretically be formatted at double density only if no information has been written on the disk in high density, or the disk has been thoroughly demagnetized with a bulk eraser, as the magnetic strength of a high density record is stronger and overrides lower density, remaining on the disk and causing problems.

[Cymru]

Yep, that's what I was referring to, but it gets a bit more complex when you search out the properties of the media and the magnetic field.