Re: Can this CD/Floppy Behaviour be Done? [offtopic?]
John Cochran (kernel@fiawol.org)
Fri, 11 Dec 1998 05:27:35 -0500 (EST)
Steven S. Dick wrote:
> David Balazic wrote:
> >>Dennis Grant <dg50@daimlerchrysler.com> wrote:
> >>> I was futzing with my system in user-space last night, and I wonder if
> >>> there's a way to do something:
> >>>
> >>> One of the behaviours I really miss from my Amiga days is the ability to
> >>> auto-detect and auto-mount removeable media filesystems.
> >>>
> >
> >Neither on the Amiga, the OS must poll the status.
> >Even more , if the drive is empty , it will report empty
> >until you move the heads ( and a floppy is inserted ).
> >I never understand why is this ... ( the head movement requirement )
>
> If I recall correctly, head _movement_ is not required, although
> a head _seek_ is required.
>
> If you seek to the track the head is already on, it is enough.
Nope, I pretty certain that _movement_ was required. When I had my Amiga,
I _always_ needed to keep a diskette in the drive to stop the annoying
click, click, click,... noise that came out of the drive every few
seconds whenever it was empty. Also, if I recall correctly, the Amiga
took an idea from the Apple and performed a _lot_ of low level stuff
in the CPU instead of having a more capable floppy disk controller.
Some things the CPU had to do:
1. Keep track of which track the head was on and send individual
phases to the stepper motor to change tracks.
2. Encode the data being sent to the floppy using MFM (and decode
data received)
Later,
John Cochran
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