Re: Did Commodore cheat with the quad density floppies?

Den Sun, 6 Jan 2019 14:10:40 +0100 skrev Gerrit Heitsch
<gerrit@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.

In hindsight, an AGA Amiga could have had HD capability when in a 31kHz
mode without much change of the hardware. It could also have had 16bit
audio for each channel.

But to save money, the didn't redesign Paula so the old OCS/ECS Paula
crippled the audio and floppy (and for that sake also the serial port)
of the AGA machines.
 
> Compared to that, I bet the half speed drives were more cost
> effective.


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