Re: Of removable devices

From: Vojtech Pavlik (vojtech@suse.cz)
Date: Mon Feb 21 2000 - 03:27:29 EST


On Mon, Feb 21, 2000 at 09:23:59AM +0100, David Balazic wrote:
>
>
> Vojtech Pavlik wrote:
> >
> > On Fri, Feb 18, 2000 at 02:48:16PM +0100, David Balazic wrote:
> >
> > > > > At the same time - the fix is hardware, the PC isnt fixable for this the
> > > > > CD-ROM drives are. The 2.2.x supermount stuff does that bit right
> > > >
> > > > Exactly. As far as there are no automatic gear for floppies you can not
> > > > avoid manual unmount if you want reliable work.
> > >
> > > But you CAN ,as at least AmigaOS proves.
> > >
> > > If you didn't understand it at first, I'll repeat it :
> > > IT CAN BE DONE !!!!!!
> >
> > Yes, but AmigaOS didn't do it on PC hardware. They did use the same
> > floppies PC does, but a different controller. PC floppy controller
> > updates the disk change flag only after stepping the head. If you don't
> > want to step the head constantly (and also spin the motor all the time),
> > you can't check for floppy insertion/removal easily.
>
> You just described how amiga-floppies work !
> Ten bonus points for you :-)

Well, yes, but on Amiga you can step from track 0 to track 0. Not
possible on a PC controller.

> Except they didn't have to turn the motor on.

Another difference, yes.

> And I'll repeat this question again :
> Whose idea was to require a head-step for the update ?

Don't know, it's in the floppy interface standard ...

-- 
Vojtech Pavlik
SuSE Labs

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