Re: Did Commodore cheat with the quad density floppies?

From: Gerrit Heitsch <*gerrit_at_laosinh.s.bawue.de*> Date: Sun, 6 Jan 2019 14:10:40 +0100 Message-ID: <2914cb91-15d5-a767-39b9-e7b7187ce13f@laosinh.s.bawue.de> · gerrit_at_laosinh.s.bawue.de

On 1/6/19 1:04 PM, smf wrote:
> On 05/01/2019 21:13, Mia Magnusson wrote:
> 
>> It requires HD media and achieves a worse result than MFM (Amiga MFM 22
>> sectors per track).
> 
> I am not sure it needs HD media, or whether the drive detecting the 
> notch in the HD media affects the filtering.
> 
> It is worse than MFM 22 sectors per track, but to achieve those extra 3 
> sectors per track needs double the rate.
> 
> Which commodore unfortunately implemented using a half speed motor, 
> which makes the drives rare as hens teeth.
> 
> Not exactly efficient.

Well, the alternative would have been to redesign PAULA and AGNUS since 
it would have meant more DMA slots for floppy data and higher speed 
shift registers in PAULA.

Compared to that, I bet the half speed drives were more cost effective.

  Gerrit