running exe and RAM questions in MS DOS

[pchalla90]

Hey guys,

I'm working on a project for school and I want the most resources available to run my data and speed intensive program. I decided to build a computer, single core (because I don't know how to program multiple cores), that I can boot to MS DOS on. Then, I'd compile my program from C++ to a .exe and run it that way.

I got my hands on DOS 7.1 from a CNET download. My flash drive is now bootable with DOS. When I tried to run my program, it popped back with an error. I can't run my exe file in DOS. So I created a simple hello world file. It couldn't run that either.

What am I doing wrong?

On top of that, I have 1gb of RAM. DOS only recognizes about 65mb of it. Is there any way I can get at the rest of it? I'm running image processing stuff, so I want a large amount of RAM available. I know that 65mb was the max back when DOS 7.1 came out, but can I override that?

Thanks.

[Ned Seagoon]

You've downloaded a version of DOS and installed it on a computer that you built. However have you configured DOS.

It will actually only use 640kb of your RAM without the addition of memory managers, and you need a properly configured autoexec.bat and a config.sys to load the memory manager. For a little for information read this

Does the operating system that you have installed have all this?

Also what compiler did you use to generate the executable from your C++ file?

[pchalla90]

Thanks for your reply.

I'm using DevC++ which has it's own compiler.

And this is how I made my flash drive bootable. It comes with its own DOS to install.

http://download.cnet.com/DOS-on-USB/...ml?tag=mncol;2

It takes about five minutes after downloading to have DOS up and running on a flash drive, if you have a free flash drive. I followed the ReadMe file and if it wasn't mentioned in that file, I went with the standard settings, meaning whichever the DOS installer had automatically highlighted.

It didn't work for me. When I tried booting to it, it showed me the Windows DOS logo and then an error saying something about how EMM386.exe found an error at [some memory address, don't remember off the top of my head, but I can get it to you if you want]. It also mentioned that in order to minimize data loss, EMM386 shut down my computer. I never got to a command line.

I also distinctly remember something about error #n9 where the n is superscripted.

I can get you the exact error message if you want.

After getting this error message, I formatted my drive again and reinstalled DOS, making sure to actually read the prompts and choose the settings that I thought were what was needed or what was right before hitting enter.

I got the same error message, including the same Memory address. I thought that was weird.

I tried booting to the flash drive on a laptop, and not the computer I built, and I got the same exact error message, even with the same memory address.

So I assumed that emm386.exe was buggy, so I simply deleted it from the flash drive and booted to it.

It worked fine, then. I got to command line and was able to do basic things including creating and editing text files, viewing the computer's technical information, and so on. I was even able to restart from command line.

But now I only have access to a portion of my 1 GB RAM stick and I can't run a complex .exe, or even a simple one.

The exe's run on my laptop just fine with Windows 7, and I've tested them in XP and Vista as well.


So if you have like fifteen minutes and an empty flash drive bigger than like 16MB (I think that's the minimum requirement), can you tell me what I did wrong?

I'll get back to you with the exact error messages when I run my .exe's and the one from EMM386.


Thanks!

[Ned Seagoon]

Sorry, I can't diagnose from that, too many variables.

[pchalla90]

Okay, thanks anyway.

If you get a chance, can you try the DOS flash drive installer just to see the settings options that I was given?

If you would prefer, I can reinstall it to my own flash drive, take pictures of the screens and post them somewhere for you to see.


If you can't, that's fine.

Thanks again!

[Ned Seagoon]

As I said too many variables, you've built a computer specifically to do the job so why are you running the operating system from a flash drive? If it was me doing this I would eliminate one of those variables and get rid of the flash drive and install DOS on the HDD and test everything from there.

[pchalla90]

Okay, so I used some of the advice you gave me and a lot of brute force attempts to solve my issue.

I reinstalled a proper version of EMM386.exe and I now have one gig of RAM. On top of that, I was able to debug the issue. I need to compile the files on the DOS computer. I found DJGPP and used that. Once properly installed, it works wonderfully!

So I have one gig of RAM and can run even complex exe files.



Now for another question. Do you know of a way to read data from a USB webcam?

Do I need to write my own drivers for that or is that unnecessary?

Thanks.

[Ned Seagoon]

Glad you got the original problem sorted out.

The only USB web cams I am familiar with use drivers that are designed to work with windows, not sure how you would use such a device in DOS. Perhaps someone else can come to your aid?