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.com vs .exe

DarkEmpire · 2002-06-27T21:08:04

Hi, Is it possible to create a ".com" executable with Visual C++ 6 ? or can we create only ".exe" executable ? Are ".com" smaller than ".exe" ? Are there advantages ? Thanks for your help

General and Gameplay Programming Programming

Started by DarkEmpire June 25, 2002 04:28 PM

27 comments, last by DarkEmpire 21 years, 9 months ago

Michalson

1,657

June 26, 2002 08:36 PM

quote:Original post by Martee
You misspelled ''over 20 years''

I''m guessing your part of the Windows 95 generation? Windows 3.1 (a shell over DOS) only became widespead at the beginning of the 90s. Even when people where using 3.1 DOS (which 3.1 ran on top of) was still used for almost every game. DOS only died sometime after Windows 95 (August 1995) came out, and even then it was still alive as a good platform for games for some time. So even if you consider the old shell Windows to have somehow made DOS obsolete, that would be 12-13 years at best. Frankly 5 years sounds about right for when mainstream DOS support stopped (around the time good 3D accelerators where making their mark)

DerekSaw

243

June 26, 2002 09:12 PM

quote:Original post by Leadorn
but what about protected mode.

Pmode one large memory adress no segment?

Hmm... I''m not sure about this. I believe they don''t have segment anymore. That''s why we don''t have any problem to allocate one large block (few megs per block

from the heap.

Also, which Pmode you are talking about? The one ''implemented'' by DOS4G/W, CWSDPMI..., or our Windows 32bit EXE? I think they work somewhat differently (though almost similar).

"after many years of singularity, i'm still searching on the event horizon"

Martee

476

June 26, 2002 09:14 PM

Er ... you missed my point. I wasn''t talking talking about ''market share'' obselecence, I was talking about ''technological'' obselecence. Since it''s creation in 1981, DOS has always been a poorly designed, technically inept operating system.

And it was a joke. Notice the smiley?

ReactOS - an Open-source operating system compatible with Windows NT apps and drivers

TheMuuj

122

June 27, 2002 08:58 AM

I would say that as soon as PCs with 4MB of RAM were commonplace, then DOS was effectively obsolete (with respect to technology). When did OS/2 first come out?

DOS was designed to run on slow systems with very little memory. Over the years it was added to in order to keep up with new PC technologies (hard disks, extended memory, etc.). In the early days DOS did its job well and nothing more was needed of it. If it had been possible to use Unix effectively on early PCs, I''m sure it would have happened.

And all Windows95 did was extend DOS beyond its lifetime. Therefore, I believe that even Windows95 was also obsolete from day one. So was Windows 98. WindowsME was so obsolete it wasn''t even funny.

This doesn''t mean they were worthless (except for WindowsME :-)).

The use of technology lags behind the development of technology. In DOS''s case, this lag was exaggerated.

--TheMuuj

--TheMuuj

Puzzler183

540

June 27, 2002 09:32 AM

OK. I will explain protected mode. There are not three or four different types of PM. There is one type. Windows uses protected mode to create segemnt descriptors for and exe when it starts. Got it now? Try reading about it on the net.

uNiQue0815

122

June 27, 2002 11:31 AM

why should anyone want to create a .com file, today ??
for what would it be needed to have an .com/.exe that's so small ?
did you buy a new C64 with windows-emulator & there's not enough ram left for loading .com/.exe files >500 bytes ???
or are you planning to write a virus that's oh-so-small & kicks the whole computer-world's ass ?

in 1st case i would think about it again, and in 2nd case i would prefer assembly language

517 bytes ?? how much smaller do you want to get an .exe file ?
did you consider that an .exe has a header with a certain size ?
even witout any code, you would have a file > 0.

btw.: do you want it to be a win32-app ?? then you should
1) quickly forget your plans about using .com-files
2) quickly forget your plans of having small .exe-files
3) (quickly dump your C64/win-emu & buy a pc

)
4) ...

and now some comment about protected-mode (oh... how i loved that mode... until windows came & took control about it & all the other pc-goodies

) :
protected mode is not 'implemented' in win32, dos4g/w, cwsdpmi or any other software. it's a CPU-mode. it's implemented in hardware (the CPU) ! so it can only be USED by an OS or any other program (if there's not already any OS or memory manager using it). the memory-management is NOT implemented in hardware, so the app that switched to PM (i.e. the OS) manages descriptor-tables, virtual memory, or whatever is to be done...

that's all, folks !

[edited by - uNiQue0815 on June 27, 2002 12:32:53 PM]

DrPizza

160

June 27, 2002 03:17 PM

quote:Original post by Michalson
I''m guessing your part of the Windows 95 generation? Windows 3.1 (a shell over DOS) only became widespead at the beginning of the 90s. Even when people where using 3.1 DOS (which 3.1 ran on top of) was still used for almost every game. DOS only died sometime after Windows 95 (August 1995) came out, and even then it was still alive as a good platform for games for some time. So even if you consider the old shell Windows to have somehow made DOS obsolete, that would be 12-13 years at best. Frankly 5 years sounds about right for when mainstream DOS support stopped (around the time good 3D accelerators where making their mark)

DOs has been obsolete for considerably longer than 5 years. It has stuck around for a long time, but that doesn''t mean it wasn''t obsolete.

char a[99999],*p=a;int main(int c,char**V){char*v=c>0?1[V]:(char*)V;if(c>=0)for(;*v&&93!=*v;){62==*v&&++p||60==*v&&--p||43==*v&&++*p||45==*v&&--*p||44==*v&&(*p=getchar())||46==*v&&putchar(*p)||91==*v&&(*p&&main(0,(char**)(--v+2))||(v=(char*)main(-1,(char**)++v)-1));++v;}else for(c=1;c;c+=(91==*v)-(93==*v),++v);return(int)v;}  /*** drpizza@battleaxe.net ***/

DerekSaw

243

June 27, 2002 08:43 PM

quote:Original post by uNiQue0815

...protected mode is not ''implemented'' in win32, dos4g/w, cwsdpmi or any other software. it''s a CPU-mode. it''s implemented in hardware (the CPU) ! so it can only be USED by an OS or any other program (if there''s not already any OS or memory manager using it). the memory-management is NOT implemented in hardware, so the app that switched to PM (i.e. the OS) manages descriptor-tables, virtual memory, or whatever is to be done...

that''s all, folks !

[edited by - uNiQue0815 on June 27, 2002 12:32:53 PM]

Thanks.. you clear things up a bit for me.

... so... I would ask the whole protected-mode thingy (eg. CPU mode, priviledges, ''protections'', memory managements...) after all, still need software to manage some of it? .... hmm... maybe there''s a different in meaning between refering to CPU-mode and a pmode exe.

"after many years of singularity, i'm still searching on the event horizon"

Anonymous

June 27, 2002 09:08 PM

quote:Original post by TheMuuj
I''m pretty sure it was called ''bat2com.'' I think I got it from TSL (The Software Labs), back when I used to order shareware disks from them.
--TheMuuj

Yes!! I remember bat2com!! I used bat2com until the day I upgraded to win32 when it wouldn''t run anymore unless I booted 16bit MSDOS.

And in answering the Main topic thread:
Yes, the smaller your virus, the faster it can get away. Not all windows machines have highspeed. Also, with the exception of recursive algorithms, smaller IS faster.

-James

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