Re: Did Commodore cheat with the quad density floppies?

From: Gerrit Heitsch <*gerrit_at_laosinh.s.bawue.de*> Date: Sun, 6 Jan 2019 14:16:53 +0100 Message-ID: <bde55d65-7415-a525-f695-f9c550dc3b10@laosinh.s.bawue.de> · gerrit_at_laosinh.s.bawue.de

On 1/5/19 7:50 AM, Mike Stein wrote:
> 
> ----- Original Message -----
> From: "smf" <smf@null.net>
> To: <cbm-hackers@musoftware.de>
> Sent: Saturday, January 05, 2019 12:50 AM
> Subject: Re: Did Commodore cheat with the quad density floppies?
> 
> 
>> On 04/01/2019 23:07, Mike Stein wrote:
>>> Given two daisy-chained drives with the motor on/off signal on pin 16, how would you individually turn each separate motor on or off?
>> A jumper of course, it's a PC & so it's full of them. One more won't
>> hurt :-)
>>
> 
> ??
> 
> A normal daisy chain cable directly connects all lines, including  the motor on/off line, of the two drives together in parallel; how could a jumper anywhere turn on one motor while leaving the other turned off?

A drive that turns on the motor without the drive select line being 
active too has a design flaw. Properly designed drives would let you 
control the motor only if the DS line is active too. Yes, you would have 
to set the jumper for DS properly for each drive.

  Gerrit