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5.25" Quad Density Disks

PostPosted: Fri Mar 01, 2013 8:23 pm
by SpidersWeb
http://www.trademe.co.nz/computers/vint ... 093107.htm
SSQD

Rare as hens teeth, and if you need them, you'll know!

Soft sectored.

Re: 5.25" Quad Density Disks

PostPosted: Sat Mar 02, 2013 9:42 am
by Gibsaw
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. :)

Re: 5.25" Quad Density Disks

PostPosted: Sat Mar 02, 2013 12:39 pm
by arjoll
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).

Re: 5.25" Quad Density Disks

PostPosted: Sat Mar 02, 2013 3:09 pm
by arjoll
Yay, looks like Ron Turner is in there. I wonder if he even knows what systems these are for?

Re: 5.25" Quad Density Disks

PostPosted: Sat Mar 02, 2013 5:10 pm
by Gibsaw
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.