Issues with advanced Boom-compatible maps on DOS

[DCG Retrowave]

I mainly play DOOM on my DOS PC, but only for Vanilla/some limit-removing megawads.  This works great since I'm mostly interested in vanilla DOOM anyway, but there are some more advanced maps that interest me.  However, while I have no problem running DOOM maps in GZDoom (my main source port for advanced WADs) on Windows 10, I'd really love to play most of them on DOS.  My custom DOS gaming PC has a really nice setup at my main desk (my modern PC gets the smaller, cheaper one :D) and it's connected to my favorite PS/2 keyboard, 17 inch CRT monitor, and Roland Sound Canvas SC-88.  I could connect all of these to my modern PC (I've used a touchscreen CRT with it before :D), but something about playing on my favorite computer makes me feel happy and I'm more motivated to actually play an entire WAD rather than just a few maps.

 

Before I continue, I should probably list the specs of my DOS PC.  It has a Pentium II 350 MHz, 128MB of PC100 RAM, a 3.2GB WD Caviar HDD, ATI 3D RAGE PCI 2MB, and ESS Audiodrive 1868F.  This machine is more than capable of running Windows 98, but I already have a Pentium III Dell Dimension XPS T700r for that OS.  For 90's DOS gaming, this machine can run nearly all of my games flawlessly and more demanding titles like Quake and Tomb Raider still run very well at lower resolutions (400x300 for Quake and 320x200 for Tomb Raider).  Basically, this is one of the most capable DOS computers for running older source ports so I doubt that my hardware is holding them back, at least not significantly. 

 

Last night, I decided to try running a few BOOM WADs on my DOS PC.  I burned Boom 2.02 and MBF 2.03 to a rewritable CD as well as three Boom WADs (Lunatic, Sunlust, and Swim with the Whales).  I tried SWTW first and it loaded up just fine in Boom.  The first map ran well, although the light blue key was still a yellow key.  Everything seemed fine otherwise.  The framerate was pretty solid for the most part which was nice.  Unfortunately, the game crashed as soon as MAP02 started.  The message displayed at the DOS prompt was "Segmentation Violation."  According to the documentation included with Boom, this error is related to CWSDPMI.EXE and I would likely have better results running Boom in Windows 95/98/Me. 

 

"Due to the more sensitive nature of DPMI protected mode, BOOM is highly sensitive to accessing arrays past limit and other illegal memory usages. The usual result will be exit from BOOM with the message "Segment Violation". CWSDPMI under DOS is more sensitive than Win'95s DPMI, so some wads that won't play under DOS may still play under Win'95 in a DOS Window."

 

The same issue occurred when I tried running SWTW in MBF.  At least the light blue key displayed properly and 640x400 looks fantastic on my CRT (320x200 does too, but this was a nice enhancement :D).  I tried different versions of CWSDPMI.EXE, but it still crashed.  However, I read on another thread that using a different node builder could fix this.

 

 

I personally use ZenNode with Doom Builder 2 for my vanilla maps and it works very well.  Should I try opening SWTW's maps in Doom Builder and build the nodes with ZenNode?  If it works, hopefully it will work for other Boom WADs as well.

 

Thank you for reading this post :)

Edited September 13, 2020 by DCG Retrowave