Episode: 373
Title: HPR0373: Qemu
Source: https://hub.hackerpublicradio.org/ccdn.php?filename=/eps/hpr0373/hpr0373.mp3
Transcribed: 2025-10-07 19:18:24

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We shall see you in the next recipe.
Hi everyone, this is Klaxoo, this is HackerPublic Radio, and I'm going to be talking about
Kimu today, which no one really knows how to say it seems to be something like Kuyimu
or Kuyimu or Kuyimu, but anyway, it's a great little program for emulation.
So if you've got simple needs and you want to emulate an OS, you might want to look at
Kuyimu, and the reason I looked at it in the first place, well the first reason I looked
at it in the first place was because it was free and it was available for the Macintosh
and I needed it for the Mac, because I was stuck at work on a Mac needing something to
look at as I had from Mac OS, and so that's why I started using it, and there's a Windows
version for it, and then there's the Linux version for it.
So either way, wherever you need it, you can have it, so that's a nice feature of it,
and it's entirely free, it's a free, very free software, there's not a whole lot to
be suspicious of, in terms of affiliation with this or that company, it's free software
for emulation.
I don't do anything fancy with it myself, so in terms of virtualizing some kind of
big server kind of OS, so that you can serve lots of little thin clients, I know nothing
about that, that's nothing that I've ever done.
This is more, at least the reason that I use this is typically I get a magazine, a Linux
magazine, and you know they have this or that distro on the DVD that month, to try out
that distro I'll fire up Kuyimu, run the command, and try out the distro, or maybe I'm doing
like a tutorial or something, or a screencast, they're very handy for that as well, because
then you get a clean, isolated, untouched system that you can take screenshots of or record,
and you're not recording your own system, so that's what this little application is good
for.
Their website is at www.kuyimu.org, and you should be able to find it pretty much in any
repository that you have going for you, it's certainly in the Fedora repositories and
there's a Slack build of it, and certainly in the WN repository, so it should be everywhere
you look really, it's a very popular little application.
There's a GUI frontend for it, if you need it, although I think you'll find that you
don't need it, the GUI frontend for me, I've never been able to get it to work, but it
does exist, I haven't really taken the time to troubleshoot it, but I'll set up the machine
and try to launch it, and it just doesn't launch for some reason, it just doesn't work,
so I think you'll find that the command line stuff is sufficient anyway, the GUI is a
little bit, I don't know, excessive somehow, so you can find the GUI though, if you want
to try it out at Kimu Launcher, KEMU-Launcher, that is what it's called in the Fedora repository,
I haven't looked at it, I haven't looked for it on any other system, but I think it would
be called something like that, Kimu Launcher, but like I said, I'm not sure if it's something
that you're really going to need, okay, so after you get it installed, you really ought
to just look at the, you know, read the man page, man GUI in you, it's a pretty simple
man page, and it just gives you a really good idea of all the different options that you
have available to you, granted the first time you run it, you might not want to try every
single option that looks appealing to you, but at least you'll be familiar with more
or less what's available out there, the way I like to come to a new program like this
is sort of a, you know, you start the application kind of with a couple of options just so you
know sort of that it's working for you, and then go back and start tweaking it, that's
the way I typically do it, so, but the man page is informative and it's not overwhelming
by any means.
Well, one of the very first things you have to do is you need to create a little fake
hard drive on your real hard drive, so that Qemu can use that as its emulated hard drive,
so you can run a live CD within Qemu, but if you want to install it as a distro on a virtual
machine, then you've got to have that little container file that Qemu can look at, think
it's a real hard drive, take over format and install the distro onto it.
Now this little virtual machine doesn't have to be very large, I don't think I ever really
make them any larger than four gigabytes, so the command for that is the basic command
is Qemu-img, Qemu-img, that's a little program that creates an image for Qemu, and then
you do, so it's Qemu-img space create, space-f as an format, Q-2, that is letter Q, C-O-W,
and the number two, space, fedora.q-2, space-4G, fedora there being the distro that I'm pretending
like I'm going to emulate right now, could be anything you could call it Qemu.q-2, you
could call it slackware.q-2, you know, whatever you're going to emulate, and then the space
4G at the end is the four gigabyte definition, now that dash f format Q-2, well Q-2 is the default
format for Qemu, that's what they use, it's probably their own little format, I don't
know, but that is what you would use for Qemu if you want to know, there are other options
if you know that you're going to create it here in Qemu, and then take it out and run it
on virtual box or something like that, I've never exported a virtual machine or transferred
it or anything like that, so I know nothing about that, but you can certainly look into
it if you know that's something that you need, like if you have a site license for some
other emulator somewhere, but at home you only have Qemu, I guess there might be the ability
to do the work on Qemu, and then take it over to your work, and you know, in the big professional
emulator and import all your work, like I say I've never done it, so you also look into
that yourself, so let's just do something really simple first, and like I say, typically
I do use Qemu, just with the actual CD-RON drive of my computer, because the distro that
I'm test driving is just a distro that came with whatever DVD came with Linux format or Linux
Pro or Linux identity or whatever magazine I happen to have picked up that day.
The simple command for this would be Qemu, Qemu, space-capital-m as in machine, space-PC,
space-CPU, space-Qemu32, space-CD-RON, space-slash-dev-slash-CD-RON, space-boot, space-D, space-drive,
space-equals, till the slash-Qemu.qcout2, okay so command by command, option by option here,
Qemu, that's the application, dash-capital-m is the machine that we're trying to emulate.
You can do like a dash-capital-m and then space-question mark, and it will run Qemu up to the capital-m
and then it will see the question mark and it will just list all the different kinds of
machines that you have to choose from, if you do a CPU, space-CPU, question mark, it'll
give you a list, and one of the choices is probably the one that you'll want to choose
is Qemu32.
Now I'm running this on a 32-bit system, I've never run it on a 64-bit system, I will
very soon, there might be other options when you're running 64-bit, I'm not sure, but
the best CPU you've got to choose from right now is Qemu32, and then you do dash-space-CD
-RON, this is just defining the location of your CD-RON, it can, yes, it can be an ISO file,
so if you've downloaded an ISO image of a distro that you want to try and you obviously
don't want to burn it to disk in order to just try it out, you can run this just straight
from an ISO, which we'll do in a moment, but right now we're doing it off of an actual
CD, so that's slash-dev slash-CD-RON, and then you say space-boot, the D option, which
we're using here, tells Qemu to boot from the CD-RON rather than, for instance, C, which
would be the hard drive or whatever, you know, like in for network, I think, things like
that, and then you do the space-drive, this is telling it where the hard drive is, and
if you'll recall, the hard drive that we've created for Qemu to use is that we're QKOW2
image, so we're just defining where we stored that Qemu.QKOW2 image or Fedora.QKOW2 image,
whatever you've called it, generally I have just a Qemu.QKOW2 image in my home folder
because I'm rarely keeping these virtual machines on one distro, you know, it's like every
couple of times every month, it's getting a new distribution on it, so this is kind of
my all-purpose QKOW2 image, I just call it Qemu.QKOW2 image, but if you know that you're
emulating a Fedora install or something and you want to call your QKOW2 image Fedora.QKOW2,
that would make sense as well. You get the idea, it's up to you what you call the image,
just know where you're storing it and you're good to go. Now, after you type in that command,
which I guess I could repeat really quick, Qemu.CapitalMPC-CPU-Qemu32-CDROM-DEV-CDROM-BOOT-D-DRIVE-FILLE
EQUALS TILDAY-SLASH-Qemu.QKOW2. After you issue that command, a window will appear on
your desktop and you will have an emulated host. And first you're going to see it's
little emulated BIOS and then it will start booting from the CDROM. Once it's emulated BIOS,
recognize it's emulated hardware. And like I say, you can run this thing as a live CD or
you could, if you want to play around a little bit more, you can install it right onto your
little hard drive. And the emulated machine will think that it is an actual hard drive.
You will know that it's not your real hard drive because it's only going to be four gigs
or however large you made the drive. But just remember that in an emulated environment,
I mean as far as that emulated machine goes, all these little files and stuff that you're
throwing at it, that's all it knows about. It never will touch, it doesn't have access to
your actual hard drive. So there's really no danger of accidentally formatting your machine,
you know. It doesn't work like that. Okay, so let's move on to something that would also be
quite, quite common. Maybe you didn't get a DVD with a magazine, you just bit torrented
the latest ISO of some hot new Linux release. That is very similar. You should already have a
QCOW2 image established. If you don't, you can run the chemo-img command again. But you might want
to run chemo now with the ISO as your CD-ROM drive. So remember that in Unix and Linux and Unix
like systems, everything is a file. That everything includes CD-ROM drives. So it's just as easy
for QMU to look at slash dev slash CD-ROM as it is for it to look at, you know, fedora11.iso.
Okay, so here's what we would do if we're pointing it at this new ISO.
QMU, space-capital NPC, space-CPU, space-QMU32, space-, lowercase m512, space-USB, space-no-ACPI,
space-CD-ROM, space-tilde slash f11-preview-i686-live slash f11-preview-i686-live,
dot ISO, space-boot, space-D, space-drive, space-file equals tilde slash chemo dot QCOW2.
All right, so your eyes and ears are lasing over this point. Let's just go through it,
command by command, or flag by flag. That would be chemo. Again, the application, we're invoking,
space-capital NPC. Okay, we're still emulating a PC here, space-CPU, chemo32. Okay, we're not
emulating in, you know, a 486 machine, we're emulating like a normal modern processor,
chemo32, being the name of it. Space-lowercase m, this I just threw in because now we're getting
more elaborate. It has nothing to do with the fact that we're doing an ISO. You can use this
with the CD, with an actual CD-ROM as well. I just wanted to throw in some more more controls
so that you get an idea of what you can do with chemo. So the dash m, lowercase m, is defining
the amount of memory that you want to dedicate to this emulated PC. So I said go ahead and have 512,
because on this computer I only have a gig of memory, so I just figure I'll throw 512 at the
emulated machine, keep 512 for myself, and hope for the best. That's a little bit low to be honest.
You probably don't want to, you're not going to be working on an everyday basis on that kind of
RAM I don't think, so you might want to beef up your specs before you try this. I mean, it'll work,
it works for me fine, but I don't really do anything in the emulated machine. I just, I look at it,
play around a little bit, but if you're going to be using it in real life, you're going to,
obviously want a better, a little bit more RAM for it. And then I said dash USB, which is enabling
the USB functionality in your emulated PC. Now this is cool. It gets a little bit confusing at
times because you'll plug in a USB drive and your emulated machine might try to grab it before
your real computer does. Things like that are something to be aware of. I don't actually use it
that much, once again, it's just a question of whether you're actually going to use the emulated
PC for any real work or not, and I don't, so, but I did at one point, like when I was at work,
emulating Linux distros, just to escape, you know, the actual macOS that I had to work in,
I used it quite frequently then because I would, I would work in QMU, and then I would want to save
my work and bring it back home to use on Linux at home. So it's a cool new, it's a fairly new feature,
I'm pretty sure I could be wrong, but I'm pretty sure the USB functionality is more a little bit
recent than when I first started using QMU. So there's that option, and there's a lot of other
options that you can do. There's video card, sound card, networking, so you can play around with
that. Like I say, this is why you'd want to read the the the man page on on QMU. The next option
that I did in this big long string that I gave you was a dash no dash ACPI, and that is something
that I've found works better for, you know, certain distros. It's just whatever drivers, I guess,
are installed or however auto discovers, I don't know, but sometimes it works, you get better results
if you do the dash no dash ACPI. Space dash CD run is obviously defining the drive, and this is
where we gave it the ISO file, and this is typically, I mean, on my machine it would be tilde slash
download slash, and then the folder, which, you know, is usually pretty long, like F11 dash preview
dash, I686 dash live, and then the ISO file inside of that folder, so that would be slash F11 dash
preview dash, I686 dash live dot ISO, so that's why that was such a long string, and I think I even
cut out a folder just to be just for brevity, but you know where you download your ISOs to on your drive,
so obviously that's what you're going to be putting in as your CD run. It's that's pretty simple.
Again, you need to boot from the CD run drive, so it's the dash boot space D, and then the drive,
the hard drive that you want the emulated machine to be aware of is dash drive, and then you
define it as a file, so it's space file equals tilde slash, kimu dot qcout2, or whatever you called it.
So that's pretty simple if you, again, I mean if you kind of think about each,
each option that you're including, think about what you want to get done, it all, it all makes
a fair amount of sense. I like it, I like the command line quite a bit, I think it's, it's a very
logically done kind of way of starting all this stuff, so I don't think you're going to need
the GUI so much. Now, if at any point you've installed your distribution onto your little fake hard
drive, your qcout2 image, then you're going to want to start booting obviously not from your CD
run drive, but your hard drive. And in that case, you can still define your CD run drive, you can
still say dash CD run space dash dev slash CD run, just so that your emulated machine has a CD
run drive. It might be nice, maybe you want to pop in a music CD and import it or something
onto your emulated machine. So I mean, that's a good option to have, but the boot option, the dash
boot space D for, I don't know what it stands for drive, I guess, should not be from the DVD drive
or the CD drive, it should be from your hard drive. And to boot from the hard drive, that's dash
boot space C. And your different options there are C for hard drive A for floppy, a CD D for the CD
drive, and then in I think for network. So you've got quite a few options there, and you can use,
and you can, it's not boot, I think it's a, I think it's drive. Yeah, the space dash drive
option where you're actually defining the hard drive for the, you know, of the machine, so that
would be like, you know, the chemo dot QCow2 or Fedora 11 dot QCow2 or Debian dot QCow2, whatever
you called your little QCow2 image, you can, that's the one that you can, well, that is obviously
where you're going to be defining. Now that you've said boot from a hard drive, that's the hard drive
you want to boot from, that's important. But there are also, you know, there are snapshots and
things like that that you can take of your virtual machine. And so when you invoke your, you know,
the next time you want to run it, you can, you can start it up from a certain snapshot file.
And that kind of stuff is in the man pages. It's, it's, it's simple. It's just a matter of defining
what file you want to use for a certain function. And, and it, and it works. So, and like I say,
there's lots of options in the man page as well for your network settings, your video card,
your sound card, all that other good stuff. So just kind of take a look at the man page,
get familiar with, with at least what options are out there. And then you can start playing
around with them as, as you start being a little bit more adventurous with, with your emulated
machine. And it's getting familiar with the process of emulation is important. If you,
if you haven't emulated a machine, you probably should start because it's just something that you,
that is obviously kind of something that people expect to become a very, very big deal. In fact,
they kind of seem to expect it to become the norm, rather than an exception. So it's something
that you might want to look into, kind of start getting familiar with now. The sooner you do the
better, because at some point you're going to be dealing with emulated machines, whether you're
going to be the network administrator, creating them or a user using them. It is something that you're
going to want to know, sort of the back end of and kind of how it works and the ideas behind it.
So, um, jump on that. It's called Q, Q, Q, Emu. It is unpronounceable and it's a really cool
application. So give it a go. Oh, and thanks for listening. Really, thanks.