Author Topic: aswmonds.sys and NTVDM error  (Read 15855 times)

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Offline big

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aswmonds.sys and NTVDM error
« on: September 29, 2004, 03:22:13 PM »
Hi all. I'm a new user of Avast 4.1 Home Edition (on a WinXP-SP2 o.s.) and I have a problem.
When I try to execute the dos command 'edit.com' from a command line, it appears a window with an error message:
"The NTVDM CPU has ecountered an illegal instruction..."

If I open the CONFIG.NT file and remove the following line:

device=C:\PROGRA~1\ALWILS~1\Avast4\aswmonds.sys

then the 'edit.com' command works.

What is the function of the aswmonds.sys file and why I have to remove it from CONFIG.NT in order to execute the edit.com dos application?

Offline Eddy

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Re:aswmonds.sys and NTVDM error
« Reply #1 on: September 29, 2004, 03:32:22 PM »
FYI (For Your Info)
The NT Virtual DOS Machine (a.k.a WOW, or Windows on Windows), is a Win16 subsystem that runs under Windows NT, which allows 16-bit applications to run as if they were being executed on a DOS machine, with that machine's multitasking and segmented memory model.

Because the system is multitasked 16-bit DOS and Windows applications cannot crash NT. However, 16-bit apps within a Win16 subsystem run the exact same way as they do on a DOS/Win 3.x machine; therefore, 16-bit apps within the subsystem can crash one another, or the subsystem. To prevent this, you can launch multiple WOW subsystems as long as your program does not communicate using shared memory.


Windows NT will not allow NTVDM to execute instructions that try to directly manipulate hardware or memory locations. As a result, some DOS and Windows 3.x applications (such as games) may not run under Windows NT.

Windows XP has NO DOS like win95/98 had. Only a dos emulator.

Offline big

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Re:aswmonds.sys and NTVDM error
« Reply #2 on: September 29, 2004, 03:45:12 PM »
FYI (For Your Info)
The NT Virtual DOS Machine (a.k.a WOW, or Windows on Windows), is a Win16 subsystem that runs under Windows NT, which allows 16-bit applications to run as if they were being executed on a DOS machine, with that machine's multitasking and segmented memory model.

Because the system is multitasked 16-bit DOS and Windows applications cannot crash NT. However, 16-bit apps within a Win16 subsystem run the exact same way as they do on a DOS/Win 3.x machine; therefore, 16-bit apps within the subsystem can crash one another, or the subsystem. To prevent this, you can launch multiple WOW subsystems as long as your program does not communicate using shared memory.


Windows NT will not allow NTVDM to execute instructions that try to directly manipulate hardware or memory locations. As a result, some DOS and Windows 3.x applications (such as games) may not run under Windows NT.

Windows XP has NO DOS like win95/98 had. Only a dos emulator.
Of course, I mean the dos emulator... not the old MS-DOS or the Win95/98 Dos. ;)
Anyway, you can execute the edit command from command line without to remove that instruction from CONFIG.NT ?

Offline Eddy

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Re:aswmonds.sys and NTVDM error
« Reply #3 on: September 29, 2004, 03:54:27 PM »
XP-pro Sp2 with Avast Pro here. Got device=C:\PROGRA~1\ALWILS~1\Avast4\aswmonds.sys in config.nt, no problem with executing edit.com
« Last Edit: September 29, 2004, 04:20:45 PM by Eddy »

Offline big

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Re:aswmonds.sys and NTVDM error
« Reply #4 on: September 29, 2004, 04:16:26 PM »
I use Avast Home Edition on Win XP Home Edition too... Maybe it's a problem of Avast Home version (or XP Home)?
Anyway I'm not the only user that has this problem. Here: http://www.dslreports.com/forum/remark,11186008~mode=flat there is an user with the same problem of mine (and it has resolved it with the removal of that line in CONFIG.NT).

Offline Lisandro

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Re:aswmonds.sys and NTVDM error
« Reply #5 on: September 29, 2004, 04:39:58 PM »
Anyway, you can execute the edit command from command line without to remove that instruction from CONFIG.NT ?

Removing the drive from config.nt will, for sure, remove protection of 16-bit DOS applications. In other words, any virus running DOS under XP won't be detected. You can test this with eicar.com files and the old pkzip.exe for DOS.

Must found another way to solve the problem.
You're only by-passing it. Take care  ;)
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Offline big

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Re:aswmonds.sys and NTVDM error
« Reply #6 on: September 29, 2004, 05:48:51 PM »
Anyway, you can execute the edit command from command line without to remove that instruction from CONFIG.NT ?

Removing the drive from config.nt will, for sure, remove protection of 16-bit DOS applications. In other words, any virus running DOS under XP won't be detected. You can test this with eicar.com files and the old pkzip.exe for DOS.

Must found another way to solve the problem.
You're only by-passing it. Take care  ;)
I have tried in many ways, but that error is always there if I don't remove that line from CONFIG.NT. I hope that a new version of Avast will fix this problem.

Offline Vlk

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Re:aswmonds.sys and NTVDM error
« Reply #7 on: September 29, 2004, 06:00:58 PM »
It's been discussed for a couple of times already.

Please see e.g. http://forum.avast.com/index.php?board=2;action=display;threadid=6991;start=msg55146#msg55146


Thanks
Vlk
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Offline big

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Re:aswmonds.sys and NTVDM error
« Reply #8 on: September 29, 2004, 06:37:45 PM »
It's been discussed for a couple of times already.

Please see e.g. http://forum.avast.com/index.php?board=2;action=display;threadid=6991;start=msg55146#msg55146


Thanks
Vlk
Ohhhh... :-* thank you very much! I had't seen that thread... Excuse me!

With the reg mod, the edit.com command is working! :)

P.S.: with the reg mod of that thread, the security control of 16-bit dos applications will be active?
« Last Edit: September 29, 2004, 06:42:18 PM by big »

Offline Vlk

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Re:aswmonds.sys and NTVDM error
« Reply #9 on: September 29, 2004, 06:45:11 PM »
Quote
P.S.: with the reg mod of that thread, the security control of 16-bit dos applications will be active?


Yes, provided you leave that line in config.nt

Cheers
Vlk
If at first you don't succeed, then skydiving's not for you.