5.25" Quad Density Disks

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5.25" Quad Density Disks

Postby SpidersWeb on Fri Mar 01, 2013 8:23 pm

http://www.trademe.co.nz/computers/vint ... 093107.htm
SSQD

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Re: 5.25" Quad Density Disks

Postby Gibsaw on Sat Mar 02, 2013 9:42 am

HD formats as DD no problem at all... What it generally won't do is re-format as DD from HD.

Find a degausser or bulk eraser. :)
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Re: 5.25" Quad Density Disks

Postby arjoll on Sat Mar 02, 2013 12:39 pm

Gibsaw wrote:HD formats as DD no problem at all...

You're not going to get reliability using HD disks in a DD drive. HD formats as DD no problem in an HD drive only!

HD media has a thinner coating and double the coercivity of DD media. Thinner coating = lower read signal, higher coercivity = higher write current required.

QD is a different beast, it has the same coercivity as DD media but is certified to a higher track density (96 or 100tpi) - so it's just better quality media for drives that need it. Saying that, back "in the day" I'd never heard of problems using standard DD 48tpi media in Sord 100tpi mk III drives (and I'm guessing Commodore 8050 users found the same thing).
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Re: 5.25" Quad Density Disks

Postby arjoll on Sat Mar 02, 2013 3:09 pm

Yay, looks like Ron Turner is in there. I wonder if he even knows what systems these are for?
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Re: 5.25" Quad Density Disks

Postby Gibsaw on Sat Mar 02, 2013 5:10 pm

arjoll wrote:
Gibsaw wrote:HD formats as DD no problem at all...

You're not going to get reliability using HD disks in a DD drive. HD formats as DD no problem in an HD drive only!

Nope. Not experiencing "reliability issues". I have hundreds of them, and many Disk II's. They work fine. What doesn't work so well is overwriting HD Data. Sometimes takes several goes. Or a degausser.
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