8" disk drives and modern PCs

[Tony Duell]

> 
> On 26 Oct 2006 at 14:12, Kelly Leavitt wrote:
> 
> > My question is what is the best order to turn things on. 
> >I've always turned the drive on before powering up the PC, and 
> >turned the drive off after powering off the PC. Does this really
> >matter? I always make sure there is no disk in the drive before
> >doing any power cycling.
> 
> Given that signals on a floppy interface are active-low, I'm going to 
> venture that the sequence should be power to the CPU, then power to 

YEs, but any correctly-designed disk controller would use open-collector 
drivers, which will appear as floating outputs when powered down.

> the drive.  This should prevent spurious drive head-loads, accidental 
> writes (even if you don't think you'll ever have a disk in the drive) 
> and other nicieites.

Maybe. I don;t think it makes much difference.

I have an external drive box on my PC/XT, which contains the hard drives 
(ST412-interface) and a couple of 3.5" floppies. In order to get the hard 
drives up to speed before the machine tries to boot from them, I always 
turn the drives on first, then the CPU box. And I have nevr had any 
problems doing that.

-tony