[Qemu-devel] qemu problem (you might be my last resort)

[Qemu-devel] qemu problem (you might be my last resort)

[Robin Pfeifer]

Hello all,

I'm writing to this list because I haven't been able to locate help with 
my qemu problem anywhere else (forums, google).

When I start qemu with the following command:

qemu -cdrom /dev/cdrom -boot d -snapshot -m 256

with any bootable CD in the drive, I only get a qemu window with the 
tile 'qemu stopped'. I cannot get into the monitor by pressing ctrl + 
alt + 2 or do anything else except ctrl + c in the terminal where I 
started qemu to cancel it.

The command used to work perfectly with various versions of qemu, but 
now doesn't anymore. I've tried CVS versions after 0.6.1 stopped 
working, but to no avail.

the problem started when I tried to change the -m value to 350. 
Apparently this is not a legal value to use (maybe only realistic RAM 
levels are allowed?) - I've got 768 megs RAM, so it's not too much. The 
trouble is that nothing makes the error go away - not a reboot, not 
completely removing /tmp and /var and all their content, and I can't 
find anything else anywhere which might cause the problem. I even 
deleted all files which seemed to have anything to do with qemu 
(everything with qemu in its name) and installed a fresh version, but no 
luck. Just in case there was some remnant of a file somewhere blocking 
things (and because I had two other defunct files I couldn't get rid of 
any other way) I used reiserfsck --rebuild-tree, but still no show for 
qemu. At least the two files got corrected.

At first only my user ID had the problem, and root worked - but then I 
tried the -m 350 parameter with root, too, (not thinking, at the time, 
that it could be the cause of the problem) and since then, root hasn't 
been able to use qemu anymore either.

If I start qemu with the additional parameter -S I can still get into 
the monitor, but nothing I do there has any effect - the program still 
crashes as soon as I press c or enter cont.

Does anyone on this list have any suggestion what I can do?

Robin

Re: [Qemu-devel] qemu problem (you might be my last resort)

[Jim C. Brown]

On Wed, Mar 09, 2005 at 09:06:22PM +0100, Robin Pfeifer wrote:
> Hello all,
> 
> I'm writing to this list because I haven't been able to locate help with 
> my qemu problem anywhere else (forums, google).
> 
> When I start qemu with the following command:
> 
> qemu -cdrom /dev/cdrom -boot d -snapshot -m 256
> 
> with any bootable CD in the drive, I only get a qemu window with the 
> tile 'qemu stopped'. I cannot get into the monitor by pressing ctrl + 
> alt + 2 or do anything else except ctrl + c in the terminal where I 
> started qemu to cancel it.

"-monitor stdio" will make the monitor show up in the terminal. If the
monitor loads from there, try using 'info' command to see what qemu is doing.

> 
> The command used to work perfectly with various versions of qemu, but 
> now doesn't anymore. I've tried CVS versions after 0.6.1 stopped 
> working, but to no avail.
> 

You did build from source yourself, correct?

> 
> At first only my user ID had the problem, and root worked - but then I 
> tried the -m 350 parameter with root, too, (not thinking, at the time, 
> that it could be the cause of the problem) and since then, root hasn't 
> been able to use qemu anymore either.

if u add a new user, can that user use qemu (provided you don't try "-m 350") ?

> 
> If I start qemu with the additional parameter -S I can still get into 
> the monitor, but nothing I do there has any effect - the program still 
> crashes as soon as I press c or enter cont.
> 
> Does anyone on this list have any suggestion what I can do?
> 
> Robin
> 
> 
> _______________________________________________
> Qemu-devel mailing list
> Qemu-devel@nongnu.org
> http://lists.nongnu.org/mailman/listinfo/qemu-devel
> 

-- 
Infinite complexity begets infinite beauty.
Infinite precision begets infinite perfection.

Re: [Qemu-devel] qemu problem (you might be my last resort)

[Robin Pfeifer]

Sorry for replying so late, but apparently the answer did not pass some 
spam removal utility on the part of my e-mail provider. Not all messages 
from this list are making it through. Guess I'll have to monitor the 
archives more closely.


Jim C. Brown wrote:

 > On Wed, Mar 09, 2005 at 09:06:22PM +0100, Robin Pfeifer wrote:
 >> When I start qemu with the following command:
 >>
 >> qemu -cdrom /dev/cdrom -boot d -snapshot -m 256
 >>
 >> with any bootable CD in the drive, I only get a qemu window with the
 >> tile 'qemu stopped'. I cannot get into the monitor by pressing ctrl +
 >> alt + 2 or do anything else except ctrl + c in the terminal where I
 >> started qemu to cancel it.

 > "-monitor stdio" will make the monitor show up in the terminal. If the
 > monitor loads from there, try using 'info' command to see what qemu 
is > doing.

The monitor loads, but after displaying the 'type help' message doesn't 
react to input anymore, stopping / crashing along with qemu.

 >>
 >> The command used to work perfectly with various versions of qemu, but
 >> now doesn't anymore. I've tried CVS versions after 0.6.1 stopped
 >> working, but to no avail.
 >>

 >You did build from source yourself, correct?

At first I used the binary package, then the official sources, then a 
daily snapshot from dad-answers.com, all with the same result. In 
between I deleted all files which I could locate with 'qemu' in them in 
the hopes of gettind rid of the error, too.

 >>
 >> At first only my user ID had the problem, and root worked - but then I
 >> tried the -m 350 parameter with root, too, (not thinking, at the time,
 >> that it could be the cause of the problem) and since then, root hasn't
 >> been able to use qemu anymore either.

 >if u add a new user, can that user use qemu (provided you don't try 
"-m 350") ?

No, I tried that yesterday, but a new user gets the same error. Root 
used not to get it when the user already did, but after using -m 350 
with root, it no longer worked for root either.


 >>
 >> If I start qemu with the additional parameter -S I can still get into
 >> the monitor, but nothing I do there has any effect - the program still
 >> crashes as soon as I press c or enter cont.

Robin

Re: [Qemu-devel] qemu problem (you might be my last resort)

[Jim C. Brown]

On Fri, Mar 18, 2005 at 10:10:16AM +0100, Robin Pfeifer wrote:
> > On Wed, Mar 09, 2005 at 09:06:22PM +0100, Robin Pfeifer wrote:
> >> When I start qemu with the following command:
> >>
> >> qemu -cdrom /dev/cdrom -boot d -snapshot -m 256
> >>
> >> with any bootable CD in the drive, I only get a qemu window with the
> >> tile 'qemu stopped'. I cannot get into the monitor by pressing ctrl +
> >> alt + 2 or do anything else except ctrl + c in the terminal where I
> >> started qemu to cancel it.
> 

Out of curiosity, does it work if you use an iso image instead of /dev/cdrom?

If you "-boot a" from a floppy disk image, will that work or does it have the
same error? (You can download a FreeDOS boot disk if u don't have a way to
get a bootable floppy disk image).

> >>
> >> The command used to work perfectly with various versions of qemu, but
> >> now doesn't anymore. I've tried CVS versions after 0.6.1 stopped
> >> working, but to no avail.
> >>
> 

Does using older versions of qemu work? (Sorry if I'm asking questions that
you have already answered but I don't remember the original email).

> 
> >>
> >> At first only my user ID had the problem, and root worked - but then I
> >> tried the -m 350 parameter with root, too, (not thinking, at the time,
> >> that it could be the cause of the problem) and since then, root hasn't
> >> been able to use qemu anymore either.
> 
> >if u add a new user, can that user use qemu (provided you don't try 
> "-m 350") ?
> 
> No, I tried that yesterday, but a new user gets the same error. Root 
> used not to get it when the user already did, but after using -m 350 
> with root, it no longer worked for root either.
> 

This is the most confusing thing of all.

-- 
Infinite complexity begets infinite beauty.
Infinite precision begets infinite perfection.

Re: [Qemu-devel] qemu problem (you might be my last resort)

[Stefan Kisdaroczi]

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Hi,

Did you try to set "-L" ?
-L path  // set the directory for the BIOS and VGA BIOS

regards
kisda

Jim C. Brown wrote:
> On Fri, Mar 18, 2005 at 10:10:16AM +0100, Robin Pfeifer wrote:
>
>>>On Wed, Mar 09, 2005 at 09:06:22PM +0100, Robin Pfeifer wrote:
>>>
>>>>When I start qemu with the following command:
>>>>
>>>>qemu -cdrom /dev/cdrom -boot d -snapshot -m 256
>>>>
>>>>with any bootable CD in the drive, I only get a qemu window with the
>>>>tile 'qemu stopped'. I cannot get into the monitor by pressing ctrl +
>>>>alt + 2 or do anything else except ctrl + c in the terminal where I
>>>>started qemu to cancel it.
>>
>
> Out of curiosity, does it work if you use an iso image instead of /dev/cdrom?
>
> If you "-boot a" from a floppy disk image, will that work or does it have the
> same error? (You can download a FreeDOS boot disk if u don't have a way to
> get a bootable floppy disk image).
>
>
>>>>The command used to work perfectly with various versions of qemu, but
>>>>now doesn't anymore. I've tried CVS versions after 0.6.1 stopped
>>>>working, but to no avail.
>>>>
>>
>
> Does using older versions of qemu work? (Sorry if I'm asking questions that
> you have already answered but I don't remember the original email).
>
>
>>>>At first only my user ID had the problem, and root worked - but then I
>>>>tried the -m 350 parameter with root, too, (not thinking, at the time,
>>>>that it could be the cause of the problem) and since then, root hasn't
>>>>been able to use qemu anymore either.
>>
>>>if u add a new user, can that user use qemu (provided you don't try
>>
>>"-m 350") ?
>>
>>No, I tried that yesterday, but a new user gets the same error. Root
>>used not to get it when the user already did, but after using -m 350
>>with root, it no longer worked for root either.
>>
>
>
> This is the most confusing thing of all.
>


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Re: [Qemu-devel] qemu problem (you might be my last resort)

[Robin Pfeifer]

I have changed my subscription address as no post of this thread made it 
through the damn spam guard of my provider's. Maybe I shouldn't have 
used 'last resort' in the topic line...

Anyway:

Jim C. Brown wrote:

On Fri, Mar 18, 2005 at 10:10:16AM +0100, Robin Pfeifer wrote:
 > > On Wed, Mar 09, 2005 at 09:06:22PM +0100, Robin Pfeifer wrote:
 > >> When I start qemu with the following command:
 > >>
 > >> qemu -cdrom /dev/cdrom -boot d -snapshot -m 256
 > >>
 > >> with any bootable CD in the drive, I only get a qemu window with the
 > >> tile 'qemu stopped'. I cannot get into the monitor by pressing ctrl +
 > >> alt + 2 or do anything else except ctrl + c in the terminal where I
 > >> started qemu to cancel it.
 >

 > Out of curiosity, does it work if you use an iso image instead of
 > /dev/cdrom?

No, it doesn't, the same error appears.

 > If you "-boot a" from a floppy disk image, will that work or does it 
have the
 > same error? (You can download a FreeDOS boot disk if u don't have a 
way to
 > get a bootable floppy disk image).

That's very strange, booting from a floppy works.

 > >>
 > >> The command used to work perfectly with various versions of qemu, but
 > >> now doesn't anymore. I've tried CVS versions after 0.6.1 stopped
 > >> working, but to no avail.
 > >>
 >

 > Does using older versions of qemu work? (Sorry if I'm asking 
questions > that
 > you have already answered but I don't remember the original email).

I haven't tried older versions than 0.6.1, but that used to work before 
I tried -m 350. Then I upgraded my RAM, tried the new parameter, and 
that was it. I also tried removing the RAM again, in case there was 
something wrong with it, but that didn't change anything.

 >
 > >>
 > >> At first only my user ID had the problem, and root worked - but then I
 > >> tried the -m 350 parameter with root, too, (not thinking, at the time,
 > >> that it could be the cause of the problem) and since then, root hasn't
 > >> been able to use qemu anymore either.
 >
 > >if u add a new user, can that user use qemu (provided you don't try
 > "-m 350") ?
 >
 > No, I tried that yesterday, but a new user gets the same error. Root
 > used not to get it when the user already did, but after using -m 350
 > with root, it no longer worked for root either.
 >

 > This is the most confusing thing of all.

Stefan Kisdaroczi wrote:

 > Did you try to set "-L" ?
 > -L path  // set the directory for the BIOS and VGA BIOS

No, I didn't try that. This parameter isn't in the qemu manpage, is it? 
What am I supposed to use as directory?

Robin

Re: [Qemu-devel] qemu problem (you might be my last resort)

[Jim C. Brown]

On Sun, Mar 20, 2005 at 08:01:04AM +0100, Robin Pfeifer wrote:
> I have changed my subscription address as no post of this thread made it 
> through the damn spam guard of my provider's. Maybe I shouldn't have 
> used 'last resort' in the topic line...
> 

Same here. Lucky for me, I am the one who set up and manages the anti-spam
software.

> Anyway:
> 
> Jim C. Brown wrote:
> 
> > Out of curiosity, does it work if you use an iso image instead of
> > /dev/cdrom?
> 
> No, it doesn't, the same error appears.
> 
> > If you "-boot a" from a floppy disk image, will that work or does it 
> have the
> > same error? (You can download a FreeDOS boot disk if u don't have a 
> way to
> > get a bootable floppy disk image).
> 
> That's very strange, booting from a floppy works.
> 

You mean u get the new X window titled "QEMU", which shows the guest OS booting,
and once the booting is done the guest OS is actually usuable (at least as
usuable as it would be if it was botted on a real computer)?

Here are a few more tests to try out:

If you boot from a hard disk, no floppy or cdrom image given, does it work?

If you boot from a hard disk, cdrom iso image given, does it work? If it does
work, can you see the cdrom from the guest?

If you boot from a hard disk, /dev/cdrom given, does it work? If it does
work, can you see the cdrom from the guest?

If you boot from a floppy, cdrom iso image given, does it work? If it does
work, can you see the cdrom from the guest?

If you boot from a floppy, /dev/cdrom given, does it work? If it does
work, can you see the cdrom from the guest?

I'm trying to see if this problem is caused by trying to access the cdrom,
or if it only comes up when you try to boot from it. (BTW how many different
cdroms/cdrom images have you tested?)

> 
> Stefan Kisdaroczi wrote:
> 
> > Did you try to set "-L" ?
> > -L path  // set the directory for the BIOS and VGA BIOS
> 
> No, I didn't try that. This parameter isn't in the qemu manpage, is it? 
> What am I supposed to use as directory?
> 
> Robin
> 

-L is used to set the path for the BIOS. This directory is the one that contains
the following files:

bios.bin            ppc_rom.bin         vgabios.bin
linux_boot.bin      vgabios-cirrus.bin

E.g. if you installed to /usr/local prefix, the BIOS files are probably in
/usr/local/share/qemu.

Since booting from a floppy works, I do not think that this is a BIOS related
problem (unless you are using an old bios.bin file or somehow your bios.bin
file got slightly corrupted by mistake).

-- 
Infinite complexity begets infinite beauty.
Infinite precision begets infinite perfection.

Re: [Qemu-devel] qemu problem (you might be my last resort)

[Robin Pfeifer]

Jim C. Brown schrieb:
> On Sun, Mar 20, 2005 at 08:01:04AM +0100, Robin Pfeifer wrote:

>>>Out of curiosity, does it work if you use an iso image instead of
>>>/dev/cdrom?
>>No, it doesn't, the same error appears.
>>
>>>If you "-boot a" from a floppy disk image, will that work or does it 
>>have the
>>>same error? (You can download a FreeDOS boot disk if u don't have a 
>>way to
>>>get a bootable floppy disk image).
>>That's very strange, booting from a floppy works.
>>
> 
> You mean u get the new X window titled "QEMU", which shows the guest OS booting,
> and once the booting is done the guest OS is actually usuable (at least as
> usuable as it would be if it was botted on a real computer)?

Not quite. The first disk I tried was a very old DOS 6.0 I still have 
lying around (I haven't got that many boot floppies anymore), and it 
didn't quite finish booting - but I thought, maybe the disk is broken. 
But I have also tried a Linux-based floppy which I have used as a boot 
disk previously, and downloaded bootE and tried that, too - I'm finding 
the kernel simply stops booting after a while. It does boot normally 
during a real boot process.

But that still goes much farther than booting a cdrom image, as I 
actually get to see the BIOS being set up and the kernel being started. 
With a cdrom or image of such I immediately get a blank screen.

> Here are a few more tests to try out:
> 
> If you boot from a hard disk, no floppy or cdrom image given, does it work?

Hm, would that be something like 'qemu -hda /dev/hda1 -snapshot -m 256'? 
That gives me the same error as booting from a cdrom. hda1 should be a 
Win2000 system. When I enter a disk which is present but not bootable 
(for instance sda1, where my Linux system is located, which I boot from 
a floppy), the BIOS does appear until the obvious error message turns up 
that there is no system on the disk. The qemu window remains responsive 
and can be closed - the crashed window I get when trying to boot 
something bootable cannot be closed except with xkill or Ctrl + c in the 
terminal from which I started it.

It appears that qemu becomes weird when it encounters a boot block - 
though that doesn't explain why it does boot floppies at least up to a 
point.

That makes the remaining tests obsolete, I suppose...

> If you boot from a hard disk, cdrom iso image given, does it work? If it does
> work, can you see the cdrom from the guest?

> If you boot from a hard disk, /dev/cdrom given, does it work? If it does
> work, can you see the cdrom from the guest?

> If you boot from a floppy, cdrom iso image given, does it work? If it does
> work, can you see the cdrom from the guest?
> 
> If you boot from a floppy, /dev/cdrom given, does it work? If it does
> work, can you see the cdrom from the guest?
> 
> I'm trying to see if this problem is caused by trying to access the cdrom,
> or if it only comes up when you try to boot from it. (BTW how many different
> cdroms/cdrom images have you tested?)

I have tested a couple of live CDs, Knoppix, Kanotix, RescueCD, Insert, 
SuSE... all of which boot correctly the normal way. the Knoppix and 
Insert CDs I actually booted a couple of times successfully with qemu, 
too, before qemu began to fail me.

>>Stefan Kisdaroczi wrote:
>>
>>>Did you try to set "-L" ?
>>>-L path  // set the directory for the BIOS and VGA BIOS
>>No, I didn't try that. This parameter isn't in the qemu manpage, is it? 
>>What am I supposed to use as directory?
>>
>>Robin
>>
> 
> -L is used to set the path for the BIOS. This directory is the one that contains
> the following files:
> 
> bios.bin            ppc_rom.bin         vgabios.bin
> linux_boot.bin      vgabios-cirrus.bin
> 
> E.g. if you installed to /usr/local prefix, the BIOS files are probably in
> /usr/local/share/qemu.
> 
> Since booting from a floppy works, I do not think that this is a BIOS related
> problem (unless you are using an old bios.bin file or somehow your bios.bin
> file got slightly corrupted by mistake).
> 

If they got corrupted, they should have been replaced by now. I deleted 
all files and directories with 'qemu' in the name and installed qemu 
fresh during my attempts to get rid of the error. And the floppies at 
least boot past the BIOS, too.

Robin

Re: [Qemu-devel] qemu problem (you might be my last resort)

[Jim C. Brown]

On Sun, Mar 20, 2005 at 09:49:34PM +0100, Robin Pfeifer wrote:
> >You mean u get the new X window titled "QEMU", which shows the guest OS 
> >booting,
> >and once the booting is done the guest OS is actually usuable (at least as
> >usuable as it would be if it was botted on a real computer)?
> 
> Not quite. The first disk I tried was a very old DOS 6.0 I still have 
> lying around (I haven't got that many boot floppies anymore), and it 
> didn't quite finish booting - but I thought, maybe the disk is broken. 
> But I have also tried a Linux-based floppy which I have used as a boot 
> disk previously, and downloaded bootE and tried that, too - I'm finding 
> the kernel simply stops booting after a while. It does boot normally 
> during a real boot process.

Ok, so where does it stop booting? At what point does it freeze?

> 
> But that still goes much farther than booting a cdrom image, as I 
> actually get to see the BIOS being set up and the kernel being started. 
> With a cdrom or image of such I immediately get a blank screen.

> 
> >Here are a few more tests to try out:
> >
> >If you boot from a hard disk, no floppy or cdrom image given, does it work?
> 
> Hm, would that be something like 'qemu -hda /dev/hda1 -snapshot -m 256'? 

Probably more like 'qemu -hda /dev/hdb -snapshot -m 256' (/dev/hda1 wouldnt
work unless you have a partition table on it _or_ you set it up so that the OS
can boot off of a raw hard disk w/o a partition table (afaik this isnt even
possible w/ win2k). If you have no idea what I just said, just take my word
that /dev/hda1 wouldn't work).

> That gives me the same error as booting from a cdrom. hda1 should be a 
> Win2000 system. When I enter a disk which is present but not bootable 
> (for instance sda1, where my Linux system is located, which I boot from 
> a floppy), the BIOS does appear until the obvious error message turns up 
> that there is no system on the disk. The qemu window remains responsive 
> and can be closed - the crashed window I get when trying to boot 
> something bootable cannot be closed except with xkill or Ctrl + c in the 
> terminal from which I started it.
> 

Of course if you did use /dev/hda1 then you should have gotten 'not bootable'
error too. I'd recommend downloading the freedos 10Meg disk image, or maybe
the dlxlinux disk image that comes with bochs, and see if those hard disk
images boot.

> It appears that qemu becomes weird when it encounters a boot block - 
> though that doesn't explain why it does boot floppies at least up to a 
> point.
> 

3 ways a cdrom can be made to look bootable:

1) a part of the cdrom looks like a floppy disk, and the bios uses this to boot

2) a part of the cdrom looks like a tiny hard disd, and the bios uses this

3) the bios loads the boot program directly from the cdrom w/o any emulation

1) is the most common, and odds are good that your bootable cdroms use the
floppy disk method. (The reason this is done is for backwards compatibility
I guess.) So my guess is that it isn't the boot sector, but IDE (if I had
to guess).

Perhaps the boot disks freeze up at the point that they try to access the cdrom?
Or at least detect it?

> >I'm trying to see if this problem is caused by trying to access the cdrom,
> >or if it only comes up when you try to boot from it. (BTW how many 
> >different
> >cdroms/cdrom images have you tested?)
> 
> I have tested a couple of live CDs, Knoppix, Kanotix, RescueCD, Insert, 
> SuSE... all of which boot correctly the normal way. the Knoppix and 
> Insert CDs I actually booted a couple of times successfully with qemu, 
> too, before qemu began to fail me.
> 

These all real CDs, or have you tested images as well?

-- 
Infinite complexity begets infinite beauty.
Infinite precision begets infinite perfection.

Re: [Qemu-devel] qemu problem (you might be my last resort)

[Robin Pfeifer]

Jim C. Brown schrieb:
> On Sun, Mar 20, 2005 at 09:49:34PM +0100, Robin Pfeifer wrote:
>>>You mean u get the new X window titled "QEMU", which shows the guest OS 
>>>booting,
>>>and once the booting is done the guest OS is actually usuable (at least as
>>>usuable as it would be if it was botted on a real computer)?
>>Not quite. The first disk I tried was a very old DOS 6.0 I still have 
>>lying around (I haven't got that many boot floppies anymore), and it 
>>didn't quite finish booting - but I thought, maybe the disk is broken. 
>>But I have also tried a Linux-based floppy which I have used as a boot 
>>disk previously, and downloaded bootE and tried that, too - I'm finding 
>>the kernel simply stops booting after a while. It does boot normally 
>>during a real boot process.
> 
> Ok, so where does it stop booting? At what point does it freeze?

The BootE floppy stops while the display says 'Loading' with a row of 
dots. But when the emulation window is started, it always displays 'qemu 
stopped' for a short moment, after which the 'stopped' disappears and 
the BIOS messages appear in the window. This short moment is what the 
other attempts do not get over. The floppy emulation passes that.

>>But that still goes much farther than booting a cdrom image, as I 
>>actually get to see the BIOS being set up and the kernel being started. 
>>With a cdrom or image of such I immediately get a blank screen.
> 
>>>Here are a few more tests to try out:
>>>
>>>If you boot from a hard disk, no floppy or cdrom image given, does it work?
>>Hm, would that be something like 'qemu -hda /dev/hda1 -snapshot -m 256'? 
> 
> Probably more like 'qemu -hda /dev/hdb -snapshot -m 256' (/dev/hda1 wouldnt
> work unless you have a partition table on it _or_ you set it up so that the OS
> can boot off of a raw hard disk w/o a partition table (afaik this isnt even
> possible w/ win2k). If you have no idea what I just said, just take my word
> that /dev/hda1 wouldn't work).
> 

/dev/hdb doesn't work, I have no second IDE harddisk - I've got one IDE 
and one SCSI harddisk. /dev/hda results in the 'qemu stopped' error, hdb 
of course in a 'could not open hard disk image'.

> Of course if you did use /dev/hda1 then you should have gotten 'not bootable'
> error too. I'd recommend downloading the freedos 10Meg disk image, or maybe
> the dlxlinux disk image that comes with bochs, and see if those hard disk
> images boot.

I have downloaded the Freedos image and started it with

qemu -hda /path/to/freedos.img -snapshot

Same error: qemu stopped.

>>It appears that qemu becomes weird when it encounters a boot block - 
>>though that doesn't explain why it does boot floppies at least up to a 
>>point.
>>
> 
> 3 ways a cdrom can be made to look bootable:
> 
> 1) a part of the cdrom looks like a floppy disk, and the bios uses this to boot
> 
> 2) a part of the cdrom looks like a tiny hard disd, and the bios uses this
> 
> 3) the bios loads the boot program directly from the cdrom w/o any emulation
> 
> 1) is the most common, and odds are good that your bootable cdroms use the
> floppy disk method. (The reason this is done is for backwards compatibility
> I guess.) So my guess is that it isn't the boot sector, but IDE (if I had
> to guess).
> 
> Perhaps the boot disks freeze up at the point that they try to access the cdrom?
> Or at least detect it?
> 
>>>I'm trying to see if this problem is caused by trying to access the cdrom,
>>>or if it only comes up when you try to boot from it. (BTW how many 
>>>different
>>>cdroms/cdrom images have you tested?)
>>I have tested a couple of live CDs, Knoppix, Kanotix, RescueCD, Insert, 
>>SuSE... all of which boot correctly the normal way. the Knoppix and 
>>Insert CDs I actually booted a couple of times successfully with qemu, 
>>too, before qemu began to fail me.
>>
> 
> These all real CDs, or have you tested images as well?
> 

I have tried images of Insert and Knoppix, and all of the above as CDs.

Robin

Re: [Qemu-devel] qemu problem (you might be my last resort)

[Jim C. Brown]

On Mon, Mar 21, 2005 at 06:37:31PM +0100, Robin Pfeifer wrote:
> >>Not quite. The first disk I tried was a very old DOS 6.0 I still have 
> >>lying around (I haven't got that many boot floppies anymore), and it 
> >>didn't quite finish booting - but I thought, maybe the disk is broken. 
> >>But I have also tried a Linux-based floppy which I have used as a boot 
> >>disk previously, and downloaded bootE and tried that, too - I'm finding 
> >>the kernel simply stops booting after a while. It does boot normally 
> >>during a real boot process.
> >
> >Ok, so where does it stop booting? At what point does it freeze?
> 
> The BootE floppy stops while the display says 'Loading' with a row of 
> dots. But when the emulation window is started, it always displays 'qemu 
> stopped' for a short moment, after which the 'stopped' disappears and 
> the BIOS messages appear in the window. This short moment is what the 
> other attempts do not get over. The floppy emulation passes that.
> 

I assume Linux boot floppy stops at the same point?

> /dev/hdb doesn't work, I have no second IDE harddisk - I've got one IDE 
> and one SCSI harddisk. /dev/hda results in the 'qemu stopped' error, hdb 
> of course in a 'could not open hard disk image'.
> 
> I have downloaded the Freedos image and started it with
> 
> qemu -hda /path/to/freedos.img -snapshot
> 
> Same error: qemu stopped.
> 

I can't reproduce this error. Using latest CVS, 'qemu -m 350' works perfectly
fine for me. In fact it works fine for qemu 0.5.5 as well.
Only difference is that I use kerenl 2.4.26 and I have the rtc set to 100hz
instead of 1024hz. I also have never installed or used kqemu.

Can you run gdb on it and figure out where in the code it freezes?

-- 
Infinite complexity begets infinite beauty.
Infinite precision begets infinite perfection.

Re: [Qemu-devel] qemu problem (you might be my last resort)

[Robin Pfeifer]

Jim C. Brown schrieb:
> On Mon, Mar 21, 2005 at 06:37:31PM +0100, Robin Pfeifer wrote:
>>>>Not quite. The first disk I tried was a very old DOS 6.0 I still have 
>>>>lying around (I haven't got that many boot floppies anymore), and it 
>>>>didn't quite finish booting - but I thought, maybe the disk is broken. 
>>>>But I have also tried a Linux-based floppy which I have used as a boot 
>>>>disk previously, and downloaded bootE and tried that, too - I'm finding 
>>>>the kernel simply stops booting after a while. It does boot normally 
>>>>during a real boot process.
>>>Ok, so where does it stop booting? At what point does it freeze?
>>The BootE floppy stops while the display says 'Loading' with a row of 
>>dots. But when the emulation window is started, it always displays 'qemu 
>>stopped' for a short moment, after which the 'stopped' disappears and 
>>the BIOS messages appear in the window. This short moment is what the 
>>other attempts do not get over. The floppy emulation passes that.
>>
> 
> I assume Linux boot floppy stops at the same point?

More or less. It doesn't say 'Loading' but 'vmlinuz', but it stops after 
a number of dots.

I have just deleted all qemu files again and installed the current 
dad-answers snapshot version, first with kqemu, which still doesn't 
work, then without. The problem persists. However, I'm not sure qemu 
actually freezes, as I've thought of looking at it with 'top' - qemu is 
taking up better than 90% of CPU while running, so it seems to be doing 
something. I just can't find out what...

>>/dev/hdb doesn't work, I have no second IDE harddisk - I've got one IDE 
>>and one SCSI harddisk. /dev/hda results in the 'qemu stopped' error, hdb 
>>of course in a 'could not open hard disk image'.
>>
>>I have downloaded the Freedos image and started it with
>>
>>qemu -hda /path/to/freedos.img -snapshot
>>
>>Same error: qemu stopped.
>>
> 
> I can't reproduce this error. Using latest CVS, 'qemu -m 350' works perfectly
> fine for me. In fact it works fine for qemu 0.5.5 as well.
> Only difference is that I use kerenl 2.4.26 and I have the rtc set to 100hz
> instead of 1024hz. I also have never installed or used kqemu.
> 
> Can you run gdb on it and figure out where in the code it freezes?
> 

I have just tried that, but I don't know the first thing about gdb. I 
have started qemu with -S to make it stop soon enough, then had gdb 
attach to its process number - that results in qemu not responding to 
anything anymore. Same if I use -s to have qemu wait for gdb. I have no 
idea how to tell gdb to start qemu as a parameter, it does not work with 
including qemu's parameters in '' or "". I think it would perhaps be 
best if you just told me what to do, I'm just a little user out of his 
depth... :)

I think I'll let qemu run overnight to see whether it might not actually 
be doing something after all...

Robin