From: Michael Huth (enigma_at_mail.lipsia.de)
Date: 2005-11-02 02:14:30
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 email@example.com wrote: | | On 2005-11-01, at 23:33, Anders Carlsson wrote: | |> I always thought disks once formatted on a PC were forever |> useless on other (C64/Amiga) systems, even if the disk was of the |> right capacity. I don't know why, but I experienced R/W errors in |> particular on 3.5" DD disks once used on a PC but later |> reformatted on Amiga. | | | I never noticed that and - at some point - I passed hundreds of DD | diskettes through my workshop, which all were originally msdos | formatted. | Hmm, the magnetic properties of the disk surface should be different for HD and DD. HD drives usually use a higher current (i.e. field) to magnetize the surface. So DD disks can be formatted to HD if the surface is good enough. As far as I remember this was often used with 3.5" disks and an additional hole. Ok but if you take a HD in a DD drive it will change the direction of magnetisation not completely. f.e. if you take a HD written and the DD drive has to change the magnetisation it will change maybe 70%. Or maybe just the upper layers of the surface. At least it seems that the magnetisation does not stay for a long time. This might also be true if you use a DD disk in a HD drive, but not as strong. If you put the disk in a strong and slowly decreasing alternating magnetic field the magnetisation will probably removed. (about 1 kHz should be ok) Well but this doesn't help the question 8) So is there maybe some visible difference in the properties of the disk? (dark / light brown or maybe the thickness visible against a light?) I also heard rumors that the surface for HD and DD is the same. But this would mean that the disk once used in a HD drive is no more useable in a DD drive?!? Ciao... ...Micha -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.2 (MingW32) Comment: Using GnuPG with Thunderbird - http://enigmail.mozdev.org iD8DBQFDaBL2jH+kqnb44nMRApzbAKCxD2DEjUbfnf9j+xrPzBVW6/8YRwCfZmgd YObxW4sET0cI3b3cBW5Bm0w= =iovT -----END PGP SIGNATURE----- Message was sent through the cbm-hackers mailing list
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