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Comments on Open Source Bochs/OpenOSX's WinTel X86 Emulator
Published: 12/14/2001
Last Updated: 11/17/2003 (more reader feedback)

The Sept. 3rd, 2003 news page here had a note that the OpenOSX WinTel 1.0.1 page (Aqua GUI for open source Bochs software/X86 emulator) now lists that it's "accelerated for G5" (recompile of the GUI I assume, not the actual open-source emulator code). However note farther down they say it's only been tested with OS X 10.2.2 through 10.2.4. (G5s ship with 10.2.7). See the linked page for more details and pricing which starts at $25.
As mentioned previously, Microsoft has confirmed that current VirtualPC versions are not G5 compatible and won't be until the next major release (after v6.1). If any G5 owners try this software, let me know how well it works.

Several readers sent mails about their experience with the WinTel software, including a G5 owner. (See farther down for original comments here on this emulator from Dec. 2001.)

Latest Reader Feedback: (most recent reports first)

(added 11/17/2003)
" Just been reading the slew of negative comments about OpenOSX WinTel on your page here.
Wish I'd seen that before I parted with money for the CD edition!
Finding out that their port of the Bochs emulation runs more slowly than Virtual PC would be a pleasure. I can't get it to run at all using a carefully-created Windows 98 disk image, despite following their superficially detailed but in fact very sloppy tutorial.

While I have no programming knowledge, I'm usually pretty good at finding solutions to computer problems at an operator level. Not with this ill-thought-out product though. I''m in the UK so I'm not going to waste money phoning OpenOSX, and of course they're not responding to emailed requests for tech support.
As I've just mortgaged the wife and kids to buy a 2x2Ghz G5, I'd like to get the damned thing running simply to find out whether it's remotely usable on the fastest platform there is.
If you add this message to the rest, and its read by anyone who knows how to get round the anomalies in the tutorial (consistently confusing Drive A and Drive D is the main problem), I'd love to hear from them at brian@hancill.com
Regards from Brian "

I don't normally include reader emails in postings, but Brian wanted direct feedback/tips, so I included it.

(added 10/22/2003)
" G5 with Bochs Carbon 2.0.2 (X86 PC Emulator)
I had Bochs Carbon 2.0.2 (NOT the WinTel one; I got this off SourceForge) running on my iBook G3-600 for some time. I even managed to install Windows NT 4.0 under it! It was dog-slow, though.

However, I now have a G5 dual 2.0GHz... and Bochs runs on it. I don't have the ancient Norton Sysinfo tool that Tim S. uses, unfortunately, but just by "feel" it seems to be equal to a Pentium in the 200-400Mhz range. Responsive enough for NT.

There are issues with the PC mouse pointer tracking the Mac one, and stuff like that, but it's no longer the "utter dog" it was on my iBook. :)

I'd really like to see the Bochs folks over at SourceForge get a lot of support from people who are PC hardware gurus, since Virtual PC won't work on a G5 until some future version.
Dan B. "

(added 9/26/2003)
" I have quite a long history with the whole bochs tree on mac os, I picked up the ball on MacBochs about 4 years ago, after a gentleman named David Batterham made the first port of Bochs to the Macintosh platform. this was back before carbon existed. he and i upgraded the user interface for the mac version, and added support for the powerPC platform. This was before the Pentium cpu was emulated (386 or 486 cpu emulation only). at that time, the mac version came in two classic versions, a 68k version, and a powerpc version.

after about a year of tweeking it, I lost interest, I was able to compile it on carbon, for a version that runs in both os8/9 and os X, but my desire to continue working on it waned.

most of the user interface code that i wrote for the carbon version is still what is being used for the current bochs 2.0.2 mach-o code. the setup/config app may be cocoa, but bochs itself is carbon.

on to the important topic. here is my actual bochs 2.0.2 version, running in panther, on a 1.6ghz G5, running an ancient norton sysinfo command line tool. I think it speaks for itself.
later, Tim S. "

SI screenshot

(added 9/26/2003)
" I tried Wintel 1.0 a long time ago and it stunk.

1. Even after you migrate through their arcane way of handling CD images (can't read a CD????), it was a horrendous nightmare getting it to install. You have to do everything EXACTLY right - and most of it's unintuitive.

2. Even then, the performance is 3 levels worse than dismal. Wintel's statement that it's only slightly outperformed by VPC is completely wrong. Sure, they might have found one obscure function where Wintel is OK, but my experience shows that it's overall a terrible system. For example, VPC installs WinXP in about an hour on my Mac. Wintel using Win9x (I didn't have the patience to try WinXP) takes forever. I started it about 4:00 pm one afternoon. When I came back into work the next morning it was still not finished. It took into the next day (total of about 36 hours, if I remember correctly) just to install the OS. Then you have to deal with dog slow boot times, emulation performance and so on.

3. I contacted Wintel back then and ever got a response.

4. When Winteil 1.0.1 came out, I contacted Wintel again. I got a form letter saying that the response for my G4 Mac would be no better than Wintel 1.0.
Please encourage your readers not to waste their money.
Regards, Joe R.
Oseco, Inc. www.oseco.com. "

(added 9/25/2003)
" I tried installing bochs from the freeware, and had no luck. So I plunked down my 25 shekels and installed WinTel, and installed beautifully. The disk images that it comes with worked fine and effortlessly, but naturally, Microsoft products don't come with it, and seldom work as effortlessly. My copy of Windows98 didn't boot, though the CDdrivers that come with WinTel could read it okay. It turned out that the problem was the Windows CD itself, and I was able to boot from a friend's copy without a hitch.

The tutorial online is quite clear, and even on my 1.8MHz G5, the install took much longer than VPC5 on my 1GHz G4 machine. Once installed however, you can play with some settings (like Emulated IPS and VGA Update) to optimize the performance.

It still has the look and feel of an early release, but I hope Jeshua gets enough business so he continues to work on it. The menu items still have the default "MyApp Help" and "About MyApplication" and "Quit MyApplication" and I would love to have more thorough explanation about what "Emulated IPS" means in the documentation. He has buttons to make virtual hard drives(readable to bochs but not the Mac Finder), but I would love to see a progress bar and other buttons that will make floppy drive images in the size and shape that the boch emulator likes. I have yet to get my disk images of floppys to work with the emulator using Disk Copy. In the year that it will take Micros**t to come out with the G5 release of VPC, I hope there is enough progress from WinTel and bochs to add more enhancements that I won't feel compelled to buy it.

As it stands, it is much slower than VPC 5 on my old mac (G4 at 1GHz) and it doesn't yet connect to the internet through my LAN (the WinTel PC doesn't have a network card). Further, i don't have a very easy way to get software or data in and out of the PC since I have had problems getting bochs to recognize hard drive images (it does fine fine treating them as read only CDimages, though).
My hope is that thing will improve! Chris T."

(added 9/8/2003)
" I have a G5 1.8 Ghz and tried to install the emulation software. Basically what I found was that after Windows 2000 Professional (what I had handy) was copied and the emulation tried to boot the system, it stalled during startup. No movement of the progress bar after at least an hour.

On another note, I tried booting my G5 from my DiskWarrior 3 and Drive 10 1.1.2 disks and both failed. This happened with the "C" key down and when I selected the CDROM in Startup Disk. In all cases the machine booted to the internal hard disk drive.
Richard H., Ph.D.
Apple Certified Technical Coordinator "

I'm not that surprised about the CDs - in the past I've had to update my Discwarrior CD to boot from later macs that were released after the CD was made. I'd contact Alsoft and Drive10 to see if they are working on CD updates to address this.

(added 9/8/2003)
" I'd avoid the OpenOSX version in any case. The Bochs emulator is an interesting toy to play with, but is not really up to speed yet for real use. OpenOSX's version does not do all that much more for you. They also have some misleading advertising :

1. Their G5 claim is not really true. It works on G5's, while VirtualPC does not, but I know of no evidence that anyone has recompiled Bochs to take advantage of the G5.

2. "Treats dual processors as a single powerful processor". Completely untrue. Bochs is single threaded, so can ONLY utilize a single processor.
Keith C. "

See the older comments below from 2001 also on this subject.

(added 9/8/2003)
" You quote Jeshua Lacock as saying (older info from 2001 below)
    It is not "just a rebadging" . WinTel is our native Cocoa interface for configuring and starting Bochs - that is what we are selling, along with the inconvenience of a double-click installer and support."

"inconvenience"? Oops.
They seem a bit flakey if you ask me. The only way nonthreaded code can be sped up is if it takes advantage of the threaded windowing etc. in the native OS. There is no way nonthreaded CPU emulation is going to see a speedup.

They could theoretically have compiled for G5 without OS X 10.2.7 if they got hold of a new release of g++ but this means they would be shipping untested code ... (I had noted as of last week that their page listed G5 support but down the page noted it was tested only with 10.2.2 to 10.2.4 OS X versions, unless that has been revised on their page.-Mike.)

I am willing to be proved wrong by an unbiased review (I'd offer to do one myself if I had a G5) but I have my doubts that they are shipping anything majorly enhanced, and I have yet to hear of Bochs being anything other than a potentially functional but very slow emulator.
Philip M.
School of ITEE, University of Queensland "

(added 9/5/2003)
" I'm not running the WinTel's interface to Bochs x86 emulator on a G5, however, I might note that if one is willing to muck about in the terminal the program appears to merely be an interface to the PPC Bochs x86 emulator program which can be found here:
The one that you're looking for is Bochs-2.0.2.dmg (Which is the .dmg file for OS X, the .ppc.macos.sit file is actually for OS 9 or Classic)

For those looking for help (with anything other than the WinTel interface) one's best place to look is
this sourceforge forum
And there is a general discussion forum available here
And there are detailed instructions for making disk images of various OS's here
Hope it helps!
Josh S."

See some related comments on this in the older info from 2001 below.

(added 9/5/2003)
" I was not able to install Win95* using this software on a Dual 877 G4 with 10.2.6. The CD support included in their FreeDOS for the booting a: drive would not recognize my CD. I made an image of the Win95 install disk that was recognized. The install process made it thru copying the setup files to the created c: drive, started the Setup window, then errored-out with a Setup dialog that it couldn't read the (.CAB) file. ??

OpenOSX offers zero support, and there is no user forum. I don't believe that this is an app. for a casual user, and surely not an alternative for VPC.

* I used this factory disk to install Win95 on my older VPC 4 on 9.2.2 last month.
Regards, Bob "

(added 9/5/2003)
" I don't have a G5, but I had tried Wintel 1.0 on my PowerBook G4/800 and it stunk. Installation was a nightmare. Even after I managed to migrate through their crap of not being able to read CD drives (which was especially a pain since I was using an upgrade CD, so I had to create two drive images), it was dog slow. It took more than 24 hours just to install Windows. When I tried to run applications, it felt like I was running Windows XP on a 4 MHz 8088.

I contacted the vendor then and they never responded. I contacted them again when 1.0.1 was announced to see if they had really fixed the problems and to request a free upgrade since the previous one was so bad it was unusable. I still haven't received any response.
I'd suggest staying away.
Joe R. "

(added 9/5/2003)
" Hi Mike, I haven't tried the latest WinTel from Open OS X. But the bochs emulator that they are basing their product on is VERY slow. It is several orders of magnitude slower than VPC. On my Tibook 800 VPC got about 200 bogoMIPS with Redhat linux and bochs got about 2. Even if they have somehow speeded it up by 100% (which is very unlikely) it is not going to be close to VPC in performance.

I don't have numbers for windows, but the speed difference was about the same under win98 as well. We use one old Turbo Pascal based program in our Astronomy lab, which we need to run on our new eMacs. (We're switching 24 Dell P3 866s to eMacs this semester!) We tried several different ways to make this work, including Windows Terminal Services, WINE emulation on an Intel linux box exported via Xwindows, bochs and VPC, hoping to find a free way to do it. We wound up buying 24 VPC licenses because that was the only way to get acceptable performance. (If we had an 8 CPU windows server the terminal services probably would have worked great, but our 866 P3 couldn't support 24 simultaneous sessions).

If anyone does write in to tell you they got WinTel please try to get them to run some kind of benchmark!
Thanks again for your excellent site!
Mike C.
System Administrator "

Below are comments from the original page post in Dec. 2001)

In a follow-up to the 12/14/2001 news page post regarding WinTel being based on Open Source code, reader Tim Seufert sent comments on performance and other concerns. (I wrote Jeshua Lacock. the programmer/owner of OpenOSX.com for his take on Tim's comments. Jeshua's replies to Tim's comments are in italics-Mike.)

" I think OpenOSX.com is deliberately misleading potential customers about what this product is and what its capabilities are. Mike, I hope you can put this up on your web page so that people can get a better idea of what's going on.

[Jeshua Lacock: I do believe that you may have jumped to some conclusions.]

To start off with, their product is really just a rebadging of Bochs. Bochs is an open source x86 PC emulator which can be downloaded for free from http://bochs.sourceforge.net.

[Jeshua Lacock: It is not "just a rebadging" . WinTel is our native Cocoa interface for configuring and starting Bochs - that is what we are selling, along with the inconvenience of a double-click installer and support.

Note that we have a link on our main WinTel product home page to http://bochs.sourceforge.net.]

What OpenOSX.com adds is a pair of GUI utilities ("OpenOSX WinTel" and "OpenOSX DiskXFer") for configuring Bochs and dealing with Bochs disk images. They have also contributed a MacOS X CD-ROM driver to the Bochs project. Bochs itself, and the MacOS X / Carbon port of Bochs, are the work of other people, not OpenOSX.com.

[Jeshua Lacock: Besides the CD-ROM driver we developed, we also developed a patch for the mouse.

No where do we attempt to make an attempt to claim that the Carbon port of Bochs is our work.]

Although they avoid making specific claims, OpenOSX.com clearly wants people to think this is a practical way to run operating systems like Win95 or WinNT, and the applications which run on top of them. It is not. Bochs is slow. I mean dog slow. Bochs does not have anything like optimized emulation routines, much less processor-specific optimizations such as AltiVec enhancement. Its emulator core is straight C++, and from the way the Bochs developers are talking on their mailing list, the C++ code isn't even very well optimized as C++ code. (I'm extremely skeptical of OpenOSX.com's claim of G4 optimization. They would need to do massive rewrites of the Bochs emulator core to optimize it for *anything*, much less the G4 specifically. I suspect that if pressed, they would admit that this only means they turned on the C++ compiler's "optimize for G4" option, which is basically meaningless and doesn't even imply use of AltiVec.)

[Jeshua Lacock: Well, it is quite usable here, in my humble opinion. If I need to run a Windows 95 or a Linux program, I can. I am satisfied with the layer of compatibility it offers, and I would choice that over performance.

Yes, we enabled the AltiVec optimization at compile time, and it did significantly improve performance in performance trials.

We are also developing AltiVec accelerated screen draws, and optimizing the C++ code as much as possible.

BTW: Testing here shows it to be just a bit outperformed by Connectix's commercial product Virtual PC 5.0 on a dual processor, 800mhz G4. ]

Anybody who wants to check out the performance of Bochs can easily do so by downloading it from the Bochs homepage, http://bochs.sourceforge.net . Currently, only version 1.2.1 is available precompiled for MacOS X (OpenOSX is using 1.3p1). However, for the purpose of performance evaluation, 1.2.1 should be about the same. (The changelog shows no performance enhancements between 1.2.1 and 1.3.)

[Jeshua Lacock: Well, those binaries are not the same as ours, so I can not vouch that they will perform the same.]

Bochs 1.2.1 comes with a disk image containing DLX Linux, a very old text-only Linux distribution which uses Linux kernel version 1.3.89. Even though Linux was a *very* lightweight OS at 1.3.89, Bochs runs it *very* slowly on my dual processor G4-500. I think it's safe to say that any version of Windows would be unbearably slow.

[Jeshua Lacock: Windows 95, DOS and Linux is functional and completely usable. I do not claim that it is a speed demon, however. Nor would I / do I recommend it for intensive gaming.]

The OpenOSX.com claim that

    "Thanks to Mac OS X's advanced architecture, multiple G4 CPUs are utilized and are emulated as a single powerful Pentium(R) processor."

is either an intentional lie or a serious misunderstanding of the emulator they're rebadging. Aside from the fact that Bochs is a single-threaded emulator and therefore uses exactly one CPU (*), it is literally impossible to do what they claim. The idea that two real processors can emulate one virtual CPU faster than one real processor can do the same job is basically equivalent to the idea that a person can drive twice as fast if they use two cars instead of one. (**)

[Jeshua Lacock: Actually, our claim is accurate. This is an archtectual benfit of OS X and G4 processors. For the most part, Mac OS X treats both CPUs as if they were one, single threaded or muti-threaded processes alike benefit.

No where do we claim that, Apple does - however: it is clearly evident that both processors are being used when running Bochs that is emulating a single CPU.]

Finally, OpenOSX.com has a history of not dealing in good faith with the open source community, which provides most of the software used in their products. Please see http://fink.sourceforge.net/pr/openosx.php for further details. I encourage people to avoid patronizing them until they clean up their act. (Besides which, by open source standards, their prices are pretty stiff.)

[Jeshua Lacock: I appreciate your opinions, however I must disagree with you here. We fully work with the community, and many leads of related open-source projects have actually contacted us with emails of praise. We also donate funds to many projects.

Further more, there was a posting on slashdot.org a few weeks ago with the fink link that you provided. I read 182 postings on that site, and 99% of their spoken community was in agreement with my responses and in disagreement with Mr. Pfisterer views and attitudes. The 1% that did not agree, apparently failed to grasp the full situation.

We used Fink to download some tar balls for our Gimp CD. I also used Microsoft Internet Expolorer, but Microsoft does not put up a fuss about us not giving them "fair" credit. I also used a Macintosh that is based on BSD, that receives its electricity from ....

In all fairness we have been working on adding Bochs to our Kudos page.]

(*) Part of the Bochs documentation:
http://bochs.sourceforge.net/docs-html/smp-simulation.html reveals that while Bochs can emulate a SMP x86 box, Bochs itself is single threaded. By definition, a single threaded program uses only one CPU.

Briefly put, the enemy of multiprocessing performance is synchronization (that is, when one CPU must wait for another CPU to finish doing something before it can proceed with its own work). Good multiprocessor performance absolutely depends on finding work which can be split up into asynchronous tasks such that each CPU can work independently for long periods of time. Synchronization points waste CPU cycles and incur costly interprocessor communication.

The job of emulating a single CPU is not something that can be split into asynchronous tasks. Each and every emulated instruction alters the virtual CPU's state (i.e., the values stored in its register file, condition codes, program counter, etc.). The behavior of subsequent instructions depends on that state, meaning that the emulator would have to constantly synchronize each real processor's idea of the virtual CPU's state.

With synchronization so common, the performance of a hypothetical multithreaded CPU emulator would actually be *worse* than a single-threaded CPU emulator, no matter how many real processors you could throw at the job.

The one thing that can be done is to emulate one virtual CPU on each real CPU, using one thread per virtual CPU. The only synchronization needed in this scenario is when the programs running on the virtual CPUs need to synchronize (just as they would on a real SMP x86 computer). However, as mentioned above, even though Bochs can emulate multiple virtual CPUs, they all run in a single thread on the host system, which means they all run on a single CPU.
-- Tim Seufert"

The comments on OpenOSX's web site implies they are doing more than repackaging the Bochs code however - at least per this statement:

    " OpenOSX is continuing AltiVec and non-AltiVec optimizations and developing support for networking, SoundBlaster emulation, USB and modem support. "

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