Emulate This!, Part 3

PCs by the thousands.

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Re: Emulate This!, Part 3

Anonymous's picture

I've got a question:
I'm running freebsd with bochs installed but I can't get my network up. (vmware used vmnet) Now I edited .bochsrc to this:

ne2k: ioaddr=0x240, irq=9, mac=b0:c4:20:00:00:00, ethmod=fbsd, ethdev=rl0

(rl0 = host network if
mac = default mac address)

I run bochs as root (openbsd as guest) and I set ip to hostip and gateway to host gw. Still gateway does not respond to ping. Any ideea what am I doing wrong here ?

Re: Emulate This!, Part 3

Anonymous's picture

How do you turn a *.tar image or a *.zip image into a disk image? Is this possible? Is there software to automate this?

For example, if I zip my /dev/hda1 partition, which runs Windows 2000, and I transfer it to /dev/hda2, which runs SuSe, is there a tool that can convert this *.zip file to a *.img file?

Also, what networking capabilities does Bochs have? Can I simulate a network on my computer? How do I get a simulated network card talking to a local Apache installation, to the real internet, or to another instance of Bochs?

The reason I am asking is because I would like to do some testing and design for diskless PC's, (I would like to run an internet cafe one day and want to get a head start) and I want to learn clustering also.

Thanks!

N. David Guarneri

http://ndavidg.tripod.com

bximage

Anonymous's picture

Easy program to create disk images. Use this instead of "dd".

It is interactive, asks you some nice questions, and even gives you the output for the .bochsrc file

bximage is included with bochs.

I am running win95 under bochs on a PII350 with 128MB.

The install took a couple hours, but the performance is ok.

I use it for reference during tech support. I don't think I would use it for real apps on this system, but with a 1ghz, maybe it would go ok.

Re: bximage

Anonymous's picture

attempted to install suse 8.0 after using bximage to create a 5 GB hard disk image. Used its output for the bochsrc file but it complained that the initialization parameters for the hard disk were incorrect! Perhaps I will try dd instead...

Re: Emulate This!, Part 3

Anonymous's picture

How does bochs compare to UserModeLinux ? (http://user-mode-linux.sourceforge.net)

Re: Emulate This!, Part 3

Anonymous's picture

User-mode-linux is nearly as fast as native linux, and is pretty reliable. Great if you want to do some kernel hacking, or want to learn how to set up a LAN (including NAT, routers, etc.) on a single machine. Also, it is fully user-mode, no kernel modules required, just like bochs. However, UML does not emulate devices like HD's and video cards, so if you want to run X, you'll have to set up the network to the host first, and then do a remote connection to your native X server (or use Xnest). Another pitfall is that it runs linux only, and is only for kernel hacking and user-mode things.

Bochs is VERY slow, but it emulates a lot more devices, and can (in theory) run every OS that runs natively.

Figures please

Anonymous's picture

You say it's slow, but how slow? How long to load X? Is it usable? Bogomips?!

Re: Figures please

Anonymous's picture

I get 0.81 Bogomips on a 500Mhz G4 (bochs was using about 50% of the processor)

Re: Figures please

Anonymous's picture

on my Athlon 1.2 GHz windows 95 acts like if it is working on Pentium 100 processor

Re: Figures please

Anonymous's picture

Currently, it takes roughly 50 instructions to emulate 1, but there are efforts to speed things up (before, it was "run first, then maybe optimize it"; it is now time for the "maybe" part).

As a rule of thumb, I'd suggest againt using on anything below a P2/333. OTOH, if you have a non-IA32 you don't have any choice, leave it or live with it.

Worth trying though.

Re: Figures please

Anonymous's picture

Ouch...

dlx:/# Calibrating delay loop.. ok - 0.82 BogoMIPS

This on an AMD K63/450 (gives about 900 BogoMIPS natively).

Re: Emulate This!, Part 3

Anonymous's picture

Might be advisable to mention plex86, too. Bochs is a software emulation of the x86 architecture, and is therefore painfully slow. Plex86 is based on Bochs, but uses a VMWare-like approach to "virtualise" the x86 chip, thus running multiple virtual machines at near-full speed on the x86.

See http://www.plex86.org/

Is plex still active?

Anonymous's picture

doesn't appear to be according to the CVS tree. Anyone know otherwise?

Re: Is plex still active?

Anonymous's picture

plex86 has moved to http://savannah.gnu.org/projects/plex86/, but seems to be more or less dead. let's hope they put it together, because it's a great project..

Re: Is plex still active?

Anonymous's picture

plex86 was/is written by the author of bochs

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