Opening MS-DOS prompt on Windows 95 with core=dynamic_x86 crashes the machine

[divid3byzer0]

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What operating system(s) this bug have occurred on?

Windows 11

What version(s) of DOSBox-X have this bug?

All versions

Describe the bug

Whenever I (or some other program, i.e: demodisk launchers) try to open a MS-DOS prompt while in Windows 95, the system immediately crashes if I have the core set to "dynamic_x86". This doesn't happen if the core is set to "normal".

Of course, it's still usable in "normal" but much slower and I was wondering if you guys know what is happening and if there is a fixed planned or if it is something that is not a priority.

Also, from what I've checked, this doesn't happen on Windows 98, only on Windows 95.

Expected behavior

No response

Steps to reproduce the behaviour

1. Start Windows 95
2. Open MS-DOS Prompt
3. System hangs (if core is set to dynamic_x86).

Used configuration

[sdl]
autolock=true
middle_unlock=auto

[dosbox]
title=Windows 95
memsize=32

[video]
vmemsize=8
vesa modelist width limit=0
vesa modelist height limit=0

[dos]
# Set 'ver=7.1' if using Win95 OSR2 (95B) or later
ver=7.1
hard drive data rate limit=0

[cpu]
cputype=pentium
#core=normal
core=dynamic_x86
fpu=true
cycles=max 105%

[sblaster]
sbtype=sb16vibra

[fdc, primary]
int13fakev86io=true

[ide, primary]
int13fakeio=true
int13fakev86io=true

[ide, secondary]
int13fakeio=true
int13fakev86io=true
cd-rom insertion delay=4000

[ne2000]
ne2000=true
nicirq=10
backend=pcap

[ethernet, pcap]
realnic=Realtek

[render]
scaler=none

[autoexec]
IMGMOUNT 2 hdd.img -t hdd -fs none
IMGMOUNT D cd.iso -ide 2m
BOOT C:

Emulator log

No response

Additional context

No response

[Wengier]

Indeed this problem does not occur on Windows 98. For Windows 95, I had a pre-configured Windows 95 OSR2 (version 4.0.1111) image, and using your config file in DOSBox-X appears to open the MS-DOS prompt fine on my computer:

I have not checked the original version of Windows 95 (i.e. version 4.0.950) though.

[divid3byzer0]

Hmm, actually I am using that older version (with Internet Explorer 3.0 and some other networking features installed).

This is an .img file of a clean install (only added things are Mouse.com and MSCDEX to config.sys and autoexec.bat) I've kept backed up for a long time and the one I always used if in need of a quick restore or a new Windows 95 machine.

I will try to do some more tests and ultimately just do a clean install of a newer Win95 version and report back.

[joncampbell123]

I am aware some versions of Windows 95/98 and the DOS VM (including the DOS prompt in general) have a problem with dynamic core. We're not sure what's going on yet.

[Mutamid]

On my Windows 98 in Dosbox-x, MS-DOS mode works fine when restarting Windows 98 in MS-DOS mode, starting DOS in full screen, but does not work properly when entering MS-DOS via: Start Button, All programs, MS-DOS. If I start MS-DOS, with this procedure, in a window, there is no problem. But if I start it in fullscreen (Properties Settings: Screen, and select Full Screen), then MS-DOS starts in fullscreen, but they do not appear the characters that are written, or some characters appear and then MS-DOS crashes and returns to Windows 98 graphic mode, appearing the message that there has been an illegal operation with error: FF37-8327. Or also Windows 98 and Dosbox-x. crashe.

This occurs en my Spanish Windows 98 in Dosbox.x 0.83.24, SDL1 and SDL2. It occurs the same in core=normal and corel=dynamic_86.

[divid3byzer0]

Another thing I found regarding this bug (as weird as it might be): opening the MS-DOS window with any windows desktop theme applied results in a freeze.

Doing the same with the default Windows 98 appearance (green flat color wallpaper or the blue one with Active X content enabled) works with no problem.