Re: No floppy drive in Debian-Sparc ???
On Mon, 29 Dec 2003 21:34:13 +0100 (MET)
Pieter-Paul Spiertz <pspiertz@sci.kun.nl> wrote:
> On Mon, 29 Dec 2003, Greg wrote:
>
> > someone mentioned that installing Debian on a Sparc leaves the floppy drive
> > unusable. I know this is true in OpenBSD-sparc, is this true of
> > Debian-sparc and in general of linux on sparcs? I am using a SunBlade 100
>
> See [1]. Booting from floppies on the Ultra architecture is known to fail,
> because of a bug in the OpenBoot prom. However, I have no trouble reading,
> writing and mounting /dev/fd0 on an Ultra 10 running Linux.
...
> [1] http://www.debian.org/releases/stable/sparc/ch-rescue-boot.en.html#s-boo
> t-from-floppies
This is all true, but on SunBlade100 the floppy does not work at
all, I've never been able to get the driver functional in PIO mode
on those machines.
And making the SB100 floppy work with DMA is incredibly difficult
because it requires blocking all accesses to every other ISA device in
the machine (serial, etc.) while DMA to/from the floppy drive is in progress.
The reason for this madness is that on normal x86 systems, the x86 cpu
watches a special control line on the ISA bus so that device register
accesses on the ISA bus do not occur while a DMA cycle is in progress.
None of this logic exists on UltraSPARC systems so it all must be done
in software which is incredibly difficult.
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