Hello

Compiling this code:

--------------- begin here -----------
FORMAT MZ
STACK 30h
MOV AX, CS
MOV DS, AX
MOV AH, 9
MOV DX, msg
INT 21h
MOV AX, 4C00h
INT 21h
msg DB "Hello world!$"
-------------- ends here -------------

I obtain an exe that works right into an MS-DOS windows, but gives me an error message if I click twice on it: "It isn't a valid Windows application".

Does anyone know why?

Thank you

dos programs cannot be run as normal thru windows. try running your program thru the command prompt or command.com

which version of windows are you running anyways?

Well, I believe we can run real memory programs normally. On msdos command prompt it goes well, not if i run clicking twice.

Nevertheless If i code:

---------------------- begin -------------------------
FORMAT MZ

ENTRY Principal:START
STACK 30h

SEGMENT Principal
START:
MOV AX, Datos
MOV DS, AX
MOV DX, msg
MOV AH, 9
INT 21h
MOV AX, 4C00h
INT 21h

SEGMENT Datos
msg DB "Hello world!$"
--------------------- ends here ---------------

It runs well on command ms-dos prompt and clicking twice



Postdata: I'm sorry for my english, it seems not very good...

By the way, my windows version is Windows 98, and if i don't remember wrong i probed it too on Windows XP

MOV AH,8 ;get key with out echo = pause
INT 21h

Windoze will run a DOS program but normally leaves DOS running after.
You then have to type EXIT at the prompt to end the DOS session.
The PAUSE code above is usefull for DOS programs running in Win.
Just insert it at the end of your code before AX=4C00h
Then a shortcut on your desktop to the program, change properties on the short cut to exit out of DOS when program finishes.
If you have Win98 it has a great DOS onboard that you can get to run with out runnin Windoze. I change MSDOS.SYS AUTOEXEC.BAT & CONFIG.SYS then reboot. (I made a batch file that swaps/renames files.) MSDOS.SYS for DOS just has ;FORMAT in it. The AUTOEXEC.BAT & CONFIG.SYS are just DOS type files for std DOS. MSDOS.SYS is a systems file so you need to remove it's attributes to rename/alter it.
ATTRIB -h -s -r +a msdos.sys
changes it to alterable.
ATTRIB +h +s +r msdos.sys
changes it to runable.
+Hidden +System +Readonly
Any way, you might try that, cuz asm programming for DOS in Windoze didn't work for me, but programming Windoze in DOS did.

BitDog:

Why don't you use the [menu] labels in config.sys

If you change you MsDos.sys file ( ;FORMAT line only ) you can do this

Config.sys File:

[menu]
menuitem=normal,Start Windows98 GUI
menuitem=dos,Start DOS
menudefault=normal,1
; ^ This lines tell IO.SYS loader that after 1s of displaying this menu it
;begin runing from [normal] label


[normal]

device=c:\windows\himem.sys /testmem:off
device=c:\windows\ifshlp.sys
; ^ Very important line if you have modyfied MsDos.sys file

;there add rest of your config.sys


[dos]

;there add this what you normaly have in your DOS version of Config.sys

End of Config.sys File


In autoexec.bat you can also specify config using the labels:

if %config%==normal goto normal
if %config%==dos goto dos
goto exit

:normal
rem there add Win98 version of your Autoexec


c:\windows\win.com
;^ without this line WinDows GUI will can't start
goto exit

: dos
There add you DOS standard autoexec.bat file




:exit


End of Autoexec.bat


Remember to backup your's MSDOS.SYS, CONFIG.SYS and AUTOEXEC.BAT files !!

If you have a problem - simple as


Sorry for my not perfect ENglish

I'm just wondering if anybody here nows what an "error massage" is

just kidding

Some versions of Windows refuse to run executables smaller than 512 bytes from the explorer - though they can still be executed from command line.

hmmm can only think of one explanation for this....maybe explorer checks the validatity of the exe file before it executes it?....and it just has a bad validator