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  DOS and dual core 
 
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Jules Oct 08, 2008, 06:18am EDT Report Abuse
Chatting with my tech partner the other day and he said that DOS programs will not run on dual core machines because they don't know what core to run on. I didn't know that!
Is this true? Whats the science?


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Dublin_Gunner Oct 08, 2008, 08:46am EDT Report Abuse
>> Re: DOS and dual core
I would have to say that is a load of BS.

DOS will run on a multi-core processor no problem, it just runs on Core 1.

You would however need specific software to take advantage of the other cores, but it would certainly run.

Lancool PC K62
Phenom II x3 @ 3.5Ghz
4GB DDR2-800
ASUS GTX570 DirectCU II
Shawn Langley Oct 08, 2008, 01:15pm EDT Report Abuse
>> Re: DOS and dual core
Id ditto that, otherwise how would you run Fdisk/Ghost ect....

Having voices in your head is normal. Listening to them, common. Arguing, acceptable. However, when you lose the argument, you're in trouble.
Gerritt Oct 08, 2008, 11:21pm EDT Report Abuse
>> Re: DOS and dual core
In order to be MORE specific, DOS will run on LOGICAL Core 0, which is the first physical core.

Ad Astra Per Aspera
(A rough road leads to the Stars)
We all know what we know, and everyone else knows we are wrong.
System Specifications in BIO
FordGT90Concept Oct 09, 2008, 12:35am EDT Report Abuse
>> Re: DOS and dual core
Jules said:
Chatting with my tech partner the other day and he said that DOS programs will not run on dual core machines because they don't know what core to run on. I didn't know that!
Is this true? Whats the science?

DOS is an operating system. "DOS programs" can really mean one of three things:

1) Issuing commands directly in the DOS operating system.
2) Issuing commands via an emulated DOS operating system.
3) A console which, by apperance, may be identical to DOS but it isn't.

I know modern DOS (found for sure on Windows 98 SE and up) can handle multithreading (not of the console but of the operating environment). I do not know how far back DOS multithreading support goes.

In any version of DOS Windows 98 SE and up, you can run a multithreaded application which will create multiple threads to be ran on each core. Since Windows 98 SE runs on a DOS core while Windows XP and up emulates DOS, they all treat multithreading in a similar fashion. The only variation is in underlying implementation.

I wrote a console app a while ago using .NET 3.5 (runs on Windows 98 SE through Server 2008) that is multithreaded. All it does is count up from zero for one second on every core then adds that total together. It repeats it for multiple types. It produces results something like this:

ULong scores...
0 785535137 764389093
1 1183102083 1157898423
2 1573664116 394108305
3 1966955701 777612295
4 2357274515 1172856901
5 2754047751 1568305862
6 3151547207 395339647
7 3536943039 788841761
8 3919781089 1184799427
9 4308366961 1568551868

ULong averages:
[0]: 2553721759
[1]: 977270358
[C]: 1765496058.5

Double scores...
0 361579409 184992041
1 548062964 184976435
2 733893576 370410125
3 185726784 185079624
4 371553575 179254660
5 554282092 364195035
6 740365815 549143835
7 926770101 734183778
8 1113025124 919454777
9 1299260795 1104718116

Double averages:
[0]: 683452023
[1]: 477640842
[C]: 580546432.5

Those are results from a dual-core Opteron 180 on XP x64. You can get it here:
http://fordgt90concept.homeip.net/counter.zip


What I guess that application proves and the question it raises is, where does DOS start and emulation/mimicery end? I certainly don't have an answer for that...

________________________
If I remember what I forgot, I have not forgotten it.
Dublin_Gunner Oct 09, 2008, 04:14am EDT Report Abuse
>> Re: DOS and dual core
Well the problem with DOS & emulation is that its all done in software.

If you 'emulate' DOS, is it not still DOS? I mean, its still a software application, looks the same, performs the same tasks etc - so can there really be a distinction between DOS and 'emulated' DOS?

Sure, its easy to distinguish between a piece of hardware and that hardware being emulated (like PS & SNES emulators), but emulating software? Hmm........

Lancool PC K62
Phenom II x3 @ 3.5Ghz
4GB DDR2-800
ASUS GTX570 DirectCU II
Jules Oct 09, 2008, 06:06am EDT Report Abuse
>> Re: DOS and dual core
If you 'emulate' DOS, is it not still DOS? I mean, its still a software application

Thanks for the reminder about DOS and Emulated DOS.
Well I think what he was referring to was some of the really OLD systems he goes to where the programs are in DOS and not emulated DOS.
And where the clients using them are OLD also and reluctant to upgrade and maybee they have to because their old machines have finally given up, and they find that they don't run on the newer operating systems with multi core processors.

~~+++++++^^^^^^^^^^^^^^+++++++~~
Only read the manual as a last resort.
Dublin_Gunner Oct 09, 2008, 07:15am EDT Report Abuse
>> Re: DOS and dual core
I was more or less reffering to software emulation in general. Emulating software within software really does dim the line of whats emulated or merely copied.

I understand where Ford was coming from.

Lancool PC K62
Phenom II x3 @ 3.5Ghz
4GB DDR2-800
ASUS GTX570 DirectCU II
FordGT90Concept Oct 09, 2008, 12:46pm EDT Report Abuse
>> Re: DOS and dual core
I ran into this:
http://www.gamedev.net/community/forums/topic.asp?topic_id=487...mp;#908430

As I suspected, DOS itself is a single thread; however, there is variations of DOS that are multithreaded ("dos4gw extender" is cited).

That leads me to believe that all versions of Windows are multithreaded so their underlying DOS counterpart also must be. Any OS that can run two different programs at the same time has at least primitive multithreading capability.


I've run DOS from Windows 95 on an dual CPU (quad-cores) boot disk several times in the past without problems. Whichever core DOS ends up on (usually the first one it finds) is the core it remains on until terminated.


We know DOS itself is a single-threaded environment like any console; however, that does not describe if an application ran in the environment can multithread.


When you emulate an operating system, you have to bridge the gap in functions between the real OS and the virtual OS so that the virtual OS thinks it is in a real environment. Even in Windows XP, DOS has access to practically every resource on the host PC; however, Windows XP will say no to DOS when dealing with files Windows has tied up. This is very unique to XP/Vista. In non-emulated DOS, if you tell it to delete the whole Windows directory...bye bye computer.

________________________
If I remember what I forgot, I have not forgotten it.


 

    
 
 

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