Re: [Qemu-devel] Hardware virtualization with QEMU

[andrzej zaborowski]

On 16/11/2007, Philipp Gühring <address@hidden> wrote:
> Hi,
>
> > My questions are as follows:
> > 1) I know -hdc and -cdrom cannot be called at the same time, but i have
> > no luck getting an image to be mounted with -hdb or -hdd.
>
> For -cdrom you need ISO images.
> For -hd[a-d] you need harddisk-images, which are done like this
> dd id=/dev/hda of=myimage.img
> qemu -hda myimage.img

On systems where mounting is done manually you can use the ISO
filesystem on a harddisk without problems. You can also mount
filesystems from a partitioned image (what you call harddisk image) on
a cdrom. So this is not true.

>
> You can´t dd a directory. You could mkisofs a directory or you could use the
> Samba sharing to hand over a directory.
>
> > The same image
> > I can successfully mount with -cdrom cannot be mounted with either -hdb
> > or -hdd,
>
> Then it´s likely an ISO image, and not a harddisk image.
>
> > What's up there. I could not figure out from the manuals if
> > these should just be dd'ed images a directory or iso?

dd just makes a copy. You can use the device or a dd'ed copy of the
device (image) and it makes no difference. dd and cp can often be used
interchangeably.

>
> You have to dd a whole harddisk (not just a partition)
>
> > 2) Are floppy images restricted to exactly 1.44MB created with dd? I
> > cannot mount anything with the floppy switches either which is probably
> > a size constraint I dont meet.
>
> I don´t know.
>
> > 4) What is the attainable USB speed? Full USB-1 ?
>
> I think speed is something virtual at that point, but I am not sure.

Yes, with virtual devices you can reach any speed the computer can do.
With physical devices you can probably reach "full speed" (12 MB/s) or
"slow speed" (1.5 MB/s) if your computer is fast enough.

Regards