[Qemu-devel] ecos and qemu

[Qemu-devel] ecos and qemu

[Jani Monoses]

Hello

the eCos RTOS (compiled for x86) seems to be working in qemu.
For a while I thought it wasn't since not all apps worked. I think now it is a
problem with the floppy code(either in qemu or in ecos).
The apps are built as bootable floppy images and some of them were lacking
sectors so parts of the image were NULLs leading to crashes.
If I turn those same floppy images to bootable iso-s using mkisofs and run
qemu-cdrom on them they work all the time.

Jani

[Qemu-devel] Re: ecos and qemu

[Ben Pfaff]

Jani Monoses <jani@iv.ro> writes:

> For a while I thought it wasn't since not all apps worked. I think now it is a
> problem with the floppy code(either in qemu or in ecos).
> The apps are built as bootable floppy images and some of them were lacking
> sectors so parts of the image were NULLs leading to crashes.
> If I turn those same floppy images to bootable iso-s using mkisofs and run
> qemu-cdrom on them they work all the time.

That's very interesting.  At least part of the problem I've had
with Windows NT 3.51 appears to be floppy-related.  I'll have to
see if I can try anything similar.
-- 
"Let others praise ancient times; I am glad I was born in these."
--Ovid (43 BC-18 AD)

Re: [Qemu-devel] Re: ecos and qemu

[Jani Monoses]

I'm looking at it right now.
It works also if you extend the floppy image to be 1440M.
something like this

dd if=/dev/zero of=$TMP bs=1024 count=1440
dd if=$FLOPPY of=$TMP conv=notrunc
now $TMP has the extended image.

bdrv_read() drops the last part of the image if it's not 512.
So if the last part of the image is important.... :)

Jani


> 
> That's very interesting.  At least part of the problem I've had
> with Windows NT 3.51 appears to be floppy-related.  I'll have to
> see if I can try anything similar.
> -- 
> "Let others praise ancient times; I am glad I was born in these."
> --Ovid (43 BC-18 AD)
> 
> 
> 
> _______________________________________________
> Qemu-devel mailing list
> Qemu-devel@nongnu.org
> http://lists.nongnu.org/mailman/listinfo/qemu-devel

[Qemu-devel] QEMU floppy problems (was: ecos and qemu)

[Johannes Martin]

On Fri, 23 Jul 2004, Ben Pfaff wrote:
> > For a while I thought it wasn't since not all apps worked. I think now
> > it is a problem with the floppy code(either in qemu or in ecos). The
> > apps are built as bootable floppy images and some of them were lacking
> > sectors so parts of the image were NULLs leading to crashes. If I turn
> > those same floppy images to bootable iso-s using mkisofs and run
> > qemu-cdrom on them they work all the time.
> That's very interesting.  At least part of the problem I've had with
> Windows NT 3.51 appears to be floppy-related.  I'll have to see if I can
> try anything similar.

I've got floppy problems in OS/2 and Win98 as well. Booting the
installation floppies and a win98 boot floppy both works fine, but from a
fully installed version of OS/2 and Win98 installed on disk I cannot
access the floppies at all.

The difference: booting probably goes through int13 on all systems, i.e.
through the bios, but once OS/2 and Win98 later access floppies by
programm the fdc directly. So maybe there's a bug in that part of the
emulation.

	Johannes

Re: [Qemu-devel] QEMU floppy problems (was: ecos and qemu)

[Jani Monoses]

[-- Attachment #1: Type: text/plain, Size: 80 bytes --]

and this patch fixes it :)
it's ugly though...

does it work for you guys?
Jani

[-- Attachment #2: ,l.diff --]
[-- Type: text/x-diff, Size: 1045 bytes --]

Index: block.c
===================================================================
RCS file: /cvsroot/qemu/qemu/block.c,v
retrieving revision 1.10
diff -u -r1.10 block.c
--- block.c	14 Jul 2004 17:20:30 -0000	1.10
+++ block.c	23 Jul 2004 15:12:21 -0000
@@ -311,6 +311,7 @@
 {
     int ret, n, fd;
     int64_t offset;
+    int bytes = 512;
     
     if (!bs->inserted)
         return -1;
@@ -320,7 +321,7 @@
             fd = bs->cow_fd;
             offset = bs->cow_sectors_offset;
         } else if (sector_num == 0 && bs->boot_sector_enabled) {
-            memcpy(buf, bs->boot_sector_data, 512);
+            memcpy(buf, bs->boot_sector_data, bytes);
             n = 1;
             goto next;
         } else {
@@ -335,8 +336,11 @@
             offset += sector_num * 512;
             lseek64(fd, offset, SEEK_SET);
             ret = read(fd, buf, n * 512);
+	    
             if (ret != n * 512) {
-                return -1;
+		if (ret == -1)    
+	                return -1;
+		bytes = ret;
             }
         }
     next:

[Qemu-devel] Re: QEMU floppy problems

[Ben Pfaff]

Jani Monoses <jani@iv.ro> writes:

> and this patch fixes it :)
> it's ugly though...
>
> does it work for you guys?

I was working with 1440 kB files, not odd-sized files, so I think
it's an unrelated problem.
-- 
"Implementation details are beyond the scope of the Java virtual
 machine specification.  One should not assume that every virtual
 machine implementation contains a giant squid."
--"Mr. Bunny's Big Cup o' Java"

Re: [Qemu-devel] QEMU floppy problems (was: ecos and qemu)

[Johannes Martin]

On Fri, 23 Jul 2004, Jani Monoses wrote:
> and this patch fixes it :)
> it's ugly though...
>
> does it work for you guys?

No, I cannot read any floppies on Win98 SE or OS/2.


	Johannes

Re: [Qemu-devel] QEMU floppy problems (was: ecos and qemu)

[Jani Monoses]

On Fri, 30 Jul 2004 12:01:25 +0200 (CEST)
Johannes Martin <jmartin@notamusica.com> wrote:

> On Fri, 23 Jul 2004, Jani Monoses wrote:
> > and this patch fixes it :)
> > it's ugly though...
> >
> > does it work for you guys?
> 
> No, I cannot read any floppies on Win98 SE or OS/2.

I know, my fix is for a bug in handling incomplete sectors in the qemu block
layer and not in the emulation of the fdc itself.

Jani

Re: SPAM[RBL] Re: [Qemu-devel] QEMU floppy problems

[Leonardo Marques de Souza]

For me, this patch works (Win98se + all Win patchs), for read only.

the only problem is when i try to format, crash every time;
 or when i try to write, in this case qemu crash some times.

machine: athlon-xp
Debian distribution.

Johannes Martin wrote:

>On Fri, 23 Jul 2004, Jani Monoses wrote:
>  
>
>>and this patch fixes it :)
>>it's ugly though...
>>
>>does it work for you guys?
>>    
>>
>
>No, I cannot read any floppies on Win98 SE or OS/2.
>
>
>	Johannes
>
>  
>

Re: [Qemu-devel] QEMU floppy problems (was: ecos and qemu)

[Jani Monoses]

> 
> The difference: booting probably goes through int13 on all systems, i.e.
> through the bios, but once OS/2 and Win98 later access floppies by

but the bios int13 also runs over qemu doesn't it ?

Re: [Qemu-devel] QEMU floppy problems (was: ecos and qemu)

[Johannes Martin]

On Fri, 23 Jul 2004, Jani Monoses wrote:
> > The difference: booting probably goes through int13 on all systems, i.e.
> > through the bios, but once OS/2 and Win98 later access floppies by
> but the bios int13 also runs over qemu doesn't it ?
Yes, it probably does, but it might not rely on some feature of the FDC
that OS/2 or Win98/NT need, so the bug or missing feature in the FDC
emulation will not be triggered.

	Johannes

[Qemu-devel] Re: QEMU floppy problems

[Ben Pfaff]

Johannes Martin <jmartin@notamusica.com> writes:

> The difference: booting probably goes through int13 on all systems, i.e.
> through the bios, but once OS/2 and Win98 later access floppies by
> programm the fdc directly. So maybe there's a bug in that part of the
> emulation.

That was my conclusion too when I tried to look into this.  When
NT 3.51 boots, it reads the kernel via the BIOS, but then it
fails just after it starts the kernel and resets the floppy
controller.  (It goes by quickly, but you can tell the ordering
by adding debug code to the VGA controller that outputs
characters to stdout/stderr as they're written to VGA memory and
then looking at how this output is interspersed with other debug
output.)
-- 
On Perl: "It's as if H.P. Lovecraft, returned from the dead and speaking by
seance to Larry Wall, designed a language both elegant and terrifying for his
Elder Things to write programs in, and forgot that the Shoggoths didn't turn
out quite so well in the long run." --Matt Olson

Re: [Qemu-devel] QEMU floppy problems (was: ecos and qemu)

[Karel Gardas]

On Fri, 23 Jul 2004, Johannes Martin wrote:

> On Fri, 23 Jul 2004, Ben Pfaff wrote:
> > > For a while I thought it wasn't since not all apps worked. I think now
> > > it is a problem with the floppy code(either in qemu or in ecos). The
> > > apps are built as bootable floppy images and some of them were lacking
> > > sectors so parts of the image were NULLs leading to crashes. If I turn
> > > those same floppy images to bootable iso-s using mkisofs and run
> > > qemu-cdrom on them they work all the time.
> > That's very interesting.  At least part of the problem I've had with
> > Windows NT 3.51 appears to be floppy-related.  I'll have to see if I can
> > try anything similar.
>
> I've got floppy problems in OS/2 and Win98 as well. Booting the
> installation floppies and a win98 boot floppy both works fine, but from a
> fully installed version of OS/2 and Win98 installed on disk I cannot
> access the floppies at all.
>
> The difference: booting probably goes through int13 on all systems, i.e.
> through the bios, but once OS/2 and Win98 later access floppies by
> programm the fdc directly. So maybe there's a bug in that part of the
> emulation.

That's really interesting, since few weeks ago, when I was playing with
Solaris9/x86 in Qemu I've not been able to mount floppy into this OS by
volcheck command (as docs say that's for mounting floppy) and so I gave up
and used cdrom and manually created isos for transfering necessary tarbals
to my solaris9 installation...

Cheers,

Karel
--
Karel Gardas                  kgardas@objectsecurity.com
ObjectSecurity Ltd.           http://www.objectsecurity.com