PCem – An emulator of old PC hardware platforms

I think I enjoyed tinkering with EMM386 and QEMM parameters or fiddling with device driver load order more than I did actually playing the games!

I remember the pain of trying to get just that last few bits of LMA necessary to get "Frontier Elite II" working. IIRC it needed something like 600k out of the 640k to be available, something that was nigh on impossible with the standard MS-DOS mouse drivers available at the time. They'd take up some 20k or so of the LMA, leaving my system at about 590k of free LMA, no matter how you tried to get them to use UMA.

I got given a mouse driver by a cousin who'd bought a new mouse that came with a driver that put most of itself in HMA and only a couple of k of LMA. That finally made it easy to have sufficient RAM left over.

I had a few minor issues with that driver, so I'd keep two copies of autoexec.bat around, one for when I wanted to play Frontier, and one for when I wanted to do anything else.

I really wish I would have realized how Moore's law diminished the relevance of electronic knowledge back in the late 80s. Would have made life so much easier and happy.

I got the "Sierra Space Quest" bundle in a Humble Bundle or something. So I fired up Space Quest 4 like we had on my old Mac and was assaulted by the crappy DOS era color palate. Since I originally played the game on a Mac the graphics were really disappointing. On the other hand, the game played smoothly and quickly, very much unlike my old Mac LC. I know there are some quicktime[1] events in the game that were hilariously easy on the old Mac because it ran so slowly.

[1] The "Press X to not die" kind, not the Mac video format.

It can run any OS that supports the emulated hardware, not just Windows.

Hope, PCem would happy to know that Soji Yamakawa[0] working on new open-source emulator of legendary Fujitsu FM TOWNS (model II MX) computer.[1]

[0] http://ysflight.in.coocan.jp/game/towns/townse.html

[1] https://github.com/captainys/TOWNSEMU

Generally speaking if you want to run dos games, dosbox tend to be a better choice for most games, is simpler to use and there is a bigger community around it.

however, Pcem really shine in the amount of hardware supported and better support for windows. Also it seem to be more accurate, but i, personally, never found a game that needed it, but if you have some games that don't work with dosbox it may be worth a shot.

IME it tends to run very old games written for the original PC better out of the box. With Dosbox you have to fiddle a bit with the cycles so they don't run too fast or too slow.

Bochs like performance, even worse. With Bochs I can tweak the IPS count and get a closer performance near to Qemu.

Note that i've mainly tried 86box, which is a PCem fork (but AFAIK it is kept in sync with PCem and the main difference is a nicer GUI for Windows and that it provides nightly builds optimized for various CPUs).

For DOS games, DOSBox is generally the better and -especially- faster choice with the main exception being mid80s games that assumed a 4.77MHz CPU (you can still play them on DOSBox but you need to fiddle around with the cycles and even then it assumes 1 cycle = 1 instruction, whereas PCem counts cycles correctly and also it takes into consideration the graphics card performance whereas DOSBox draws things as fast as it can).

For Windows games, assuming you cannot run them in modern Windows, it is basically the best choice - assuming you have a really fast PC, otherwise you'll get sound stuttering and slowdowns (with my AMD Ryzen 7 3700X i can emulate a Pentium 75Hz -mostly- fine but anything above that starts to cause sound to stutter).

Though in my experience 99% of the Windows games out there will work in modern Windows with something like dgVoodoo2, a framecapping tool like RTSS and perhaps adjusting the compatibility options. It might take some fiddling here and there. Notable exception being mid-2000s games with DRM.

PCem shines for emulating all the old hardware required to run old operating systems that were not DOS. VirtualBox and VMWare do not work will for this since they usually since they don't have guest extensions and working drivers for things like OS/2 2.1 and Slackware 3.0.

For a PC-XT it should be on any reasonably modern computer.

Yes, it emulates composite output for machines and cards that support it. It even emulates CGA snow if you want an authentic experience.

What would the other side of an emulated serial port look like? A socket you need to write a daemon to manage? A TCP/IP port to some other emulated device with emulated serial port? Maybe write a daemon that emulates a Hayes AT modem and lets you "call" other daemons through a mapping of the phone number to a remote IP address/port?

According to the page, it has bios roms.