I've uploaded a new binary for v11 - there were a couple of issues (incorrect memory allocation for Voodoo recompiler, and a missing compile flag) that were breaking Voodoo emulation for some people, so if anyone's been having any trouble then re-download.

here's a Quake2 video on the new version (apologies for taking a bit unorthodox route through the first level)

SarahWalker wrote:

v11 is now out. Changes since v10.1 : […]
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v11 is now out. Changes since v10.1 :

• Fixed broken 8088/8086 timing

As ever, it's at http://pcem-emulator.co.uk/

The 8088 emulation is still not quite there yet. An 8088 at 12MHz in PCem is faster than my real XT clone at 12MHz. Significantly faster for an XT and considering that the CPU on my clone is a V20...

It appears to be at least 18% faster than a real IBM XT at 4.77MHz. At 10MHz it is about 23% faster than 10MHz clones with 8088. I don't know if this is just related to the 8088 emulation or other aspects, but just wanted you to know.

Awesome work btw! I love PCem!

leileilol wrote:

here's a Quake2 video on the new version (apologies for taking a bit unorthodox route through the first level)

What are your host machine specs ?
Impressive by the way !
Once the audio latency problems will have been fixed, this will be the ultimate emulator (bye bye hardware 😉 ).

I'd appreciate any help with setting up PCem. I'm fairly new to pc emulation and I've recently been playing around with installing windows 3.1 on PCem but I'm having trouble. I've never really dealt with this level of complexity before with emulation as i've mainly used Vmware and Virtualbox before which are fairly straightforward.

If anyone has setup PCem before I could definitely use some help. I've got the roms working and in terms of hardware emulation, everything seems okay. I've also got the .img files for Windows 3.1 but now I'm at a loss for how to mount them and install them.

If anyone is wondering I'm using Award SiS 496/497 with ATI Graphics Pro Turbo (Mach64 GX) and a Pentium OverDrive/83 CPU as my PCem configuration.

Thanks

Hi, installing Windows 3.1 in PCem is similar to the way doing it in a virtual machine.
Just create a fixed disk image (Disc->Configure hard disc) and mount a DOS boot disk (Disc->Change drive A:).
Then execute fdisk and create a primary DOS partition. When finished, you can do a format c: /s.
Or alternatively use a set of DOS installation floppies and use the installer.

Note that you may have to use a modified floppy image for PCem in order to get things working, because 1.44MB and 720KB floppy sizes aren't
supported (as of PCem v10.1). You can use WinImage to change the size of your existing images.
And if you wish, you can also use WinImage to extract the content of you legit Win 3.1 images to a folder and copy it inside the image (c:\setup). Then start PCem, switch to this directory (cd c:\setup) and invoke the Windows setup (setup.exe).

And if this still doesn't work for you, just have a look at this installation video on youtube.
The basics are similar to the one of a Windows 3.1 installation.

Installing Windows 95 in PCem
https://www.youtube.com/watch?v=AeEOlvRueX8

Edit: It's also important that the HD drive geometry settings of PCem and the CMOS are equal.

Jo22 wrote:

because 1.44MB and 720KB floppy sizes aren't
supported (as of PCem v10.1).

1.44mb floppy images work fine.

720kB and 1.44MB floppy images are supported and always have been. Why wouldn't they be?

I should also point out that V10.1 is now out of date, V11 has been available for a few weeks.

Ah, thanks for the feedback people! 😊
I had a few issues with certain images and changing them to 360K or 1.2MB did the job.
Plus, I couldn't verify whether PCem had full support for other formats or not (it mentions 5.25" 360K/3.5" and 5.25" 1.2M).
That's why I mentioned this as a possible work around.

As of PCem v11.. I can't speak about something I didn't use yet. I'm still running the older version here. ^^

With v11, I just get a garbled display with the the Olivetti M24 CPU emulation (no problems with v10.1).
It would also appear that XT machines are now limited to a maximum of 640kb RAM.

There is a packaging error in v11: mda.rom should be in the roms directory.Copy or move that file and that computer will work.

About XTs, they should not support more han 640Kb unless equipped with EMS. In real life that means installing a memory expansion. So, unless a XT clone had onboard support for EMS or Sarah Walker add some kind of EMS card emulation, that límite makes sense.

By ' 5.25" 360K/3.5" ' I meant ' 5.25" 360K / 3.5" handling 720K/1.44M/2.88M '. You're not the only person who got confused by this, so my wording was obviously poor. V11 changed it in any case, so it should now be more obvious.

The V11 download has been fixed.

Zup wrote:

There is a packaging error in v11: mda.rom should be in the roms directory.Copy or move that file and that computer will work.

About XTs, they should not support more han 640Kb unless equipped with EMS. In real life that means installing a memory expansion. So, unless a XT clone had onboard support for EMS or Sarah Walker add some kind of EMS card emulation, that límite makes sense.

Working now as you mentioned (apologies, I'm unfortunately not that clued up on how all the different components fit together, but luckily I understand my way around DOS and the older generation PC's).
Totally agree on your second point. Should probably have elaborated a bit more to say that I also agree of it being limited to 640KB, since most XT's didn't support more than that in real life.

But, great work so far. It's nice to see the boot up screen on an Olivetti XT PC again. It brings back some memories, since our very first PC was an Olivetti M19, which had a similar boot up screen.

Just another point (already mentioned a bit earlier in this thread).
The emulator does seems to run slightly faster than the real world CPU's.
I performed a quick benchmark on a Cyrix 486DLC 40 MHz and, using NSSI 0.60, it runs between an Intel 486DX 33 MHz & an AMD 486DX 40 MHz. In real life, my Cyrix 486DLC 40 MHz runs just below that of an Intel 486DX 33 MHz, but it's still very close (I'm unable to run NSSI 0.60 on an Intel 486DX 33 MHz - halts at the co-processor check).
Same also applies to an Intel 386DX 33 MHz & an AMD 386DX 40 MHz. Runs slightly faster on the NSSI 0.60 CPU benchmark than a real life CPU.
I'm not having much luck running Landmark 2.0 (it just freezes). I'll see what happens if I run Norton Sysinfo 8.0.

Just another question: Under the Floppy drive selection (Drive A: or Drive B:), what does the 3-mode & Dual RPM floppy drives mean? Under which configurations would they be the best to use?

Ah, okay. Thank you very much for the quick response and your understanding!
And I really was a bit confused.. I thought the floppy emulation was maybe based of an earlierer project, like a PC/XT emulator or something.. 😅
I think the drive geometry of some of my disk images were just a bit off, and a reformat in general would have solved all my problems.
Anyway, thank you very much for this awesome piece of software and for browsing by. 😊

Does anyone know what folder to install the Mach64gx drivers for Windows 95 on PCem? Because there are 4 folders that is contained in the main Mach64gx folder. There is drivers for windows 95, drivers for Windows 3.11, Utils and VESA support (Which I have no idea what that is.) I am having trouble of the one that says "Drivers for Windows 95" and in that folder are two folders of what drivers to choose. There was "64W95101 and 64W95303."and I don't know which one to choose of what is best. I choose the "6495101" folder that has the drivers but it only gave me the 16 bit colors, not 256 colors, High color (16-bit) and True color (32-bit). I don't know what folder it is to install the one that has 256 colors, High color (16-bit) and True color (32-bit).

What's the fastest CPU/chipset/video card combination for Win95 gaming in PCem? I currently have it set for a Pentium 90 on a 430VX chipset with a 4MB S3 Trio, and performance in Magic: The Gathering could be better.

PCem is designed for accuracy in the time for the CPU to complete each instruction. It also strives for similar accuracy in other parts of the emulated machine.

However, given the theoretical justification to time each CPU instruction, does it greatly improve the emulation of software or instead lead to slower emulation with little benefit? Is a more abstract, approximate, but faster level of CPU timing just as accurate in common Pentium I games?

It is hard to generalize. Some software would be expected to be more sensitive to such timing than other software. Certainly, such accuracy is very desirable in games whose speed is inherently tied to the processor and which can end up running much faster than the designers ever intended (possibly even unplayably fast). Such games were probably less common by the time the Pentium I was released.

It was brought to my attention that the Crystal Dream 2 demo (http://www.pouet.net/prod.php?which=462) does not work on PCem. I tried with V11 and various older versions, and you only get as far as the setup menu. It seems the emulator does not respond to the keyboard. I think the same happens in Crystal Dream 1 (http://www.pouet.net/prod.php?which=463), but at the end scroller: it should quit when you press a key, but it does not respond.
So there must be a bug somewhere, either in the keyboard handling, or in the interrupt controller in general.

Did anyone else notice this? And is there a fix/workaround?