Re: Docs for programming FDC on Alpha

["B. James Phillippe" <bryan terran org>]

On Wed, 16 Dec 1998, Peter W. Borders wrote:

> > > >     There are a few problems that have gone unresolved for too long
> > > > on Linux/AXP (IMHO, of course :)  The first are simply cosmetic
> > > > with the floppy driver (2.88MB thing, "bizaare FDC" message, etc),
> > > > and the second is that the ftape driver for Alpha is unmaintained.
> > > >     Can anyone point me at some documentation on how the FDC on an
> > > > Alpha is different than that on the PC?
...
> it uses a smaller pitch cable and connector. I would be willing to 
> bet that the controller is just a "standard" part as well, you should 
> be able to tell by looking at the floppy driver source in alpha linux 
> but I haven't looked recently.

It differs from the PC floppy controller as far as the Linux floppy device
driver is concerned, probably due more to DMA/memory access preferences and
BIOS calls of the underlying architecture.

1.) the floppy drive is always reported as 2.88MB under Linux.  Although I
have no factual information to back this, I suspect it is not the case
under NT or Digital UNIX (chime in here folks and lay down the slap of
reason if I am mistaken).  We all know it works properly; it should
therefore be able to be detected (cosmetically) properly.

2.) the floppy tape driver works on intel and not on Alpha.  I have taken a
quick peek at the sources to the ftape driver and I suspect this may simply
be a case of non-portable programming or apathy to support non-x86
architectures on behalf of the ftape maintainer (his personal comments to
me on the issue have lead me to this conclusion).

I have looked at the kernel sources (briefly); there is an <asm/floppy.h>
which obviously is going to contain platform-specific code to handle the
floppy driver.  From the comments in it, it would appear to the novice
(like me) that proper support for deducing the floppy type from the BIOS
(console in this case) in not implemented.  Perhaps it can't be.  Without
some documentation I won't ever know.

I am therefore wondering if anyone can provide me with locations of useful
programming information or references [in addition to the kernel] for
writing a floppy device driver for an Alpha.

thanks,
-bp
--
B. James Phillippe	. bryan@terran.org
Linux Engineer/Admin	. http://www.terran.org/~bryan
Member since 1.1.59	. finger:bryan@earth.terran.org