Runtime 6 Overflow Error using 16 bit app. HELP

[drmtesta]

I'm using XP on the latest version of VB and extensions on my Win 7 system. I use a 16 bit program that worked perfectly and then suddenly I'm getting a Runtime error '6' Overflow error.
I've tried reinstalling the program and a variety of changes to how the program launches, but nothing.
I've searched everywhere and the only information I've found relates to Visual Basic. I didn't do anything with code. .its a free standing program.
Any suggestions would be greatly appreciated. And of course I need the program to work today.
Thanks in advance,
Mark

[socratis]

and then suddenly I'm getting a Runtime error '6' Overflow error.

There is no such thing as "suddenly", "out of the blue" or similar on a computer. Something changed. From host configuration to guest updates.

• Can you share the program so we can try it?
• Can you record EXACTLY the error message, even if you have to post a screenshot?

[drmtesta]

I think I figured it out. I just got a 34" ultra wide monitor and when I go full screen, I get the error. When I make the screen about half size, the program works fine. That's strange, no?

[mpack]

Strange in what way? Even 1024x768x24bpp was high end graphics in the Win16 era. More typical was 800x600x4bpp, or less. The physical size of your screen isn't relevant, but the number of pixels very much is, as that dictates how much VRAM each screen requires. Speaking of which, I assume you checked the amount of graphics RAM you allocated to the VM.

If you want to go huge with a Win16 VM you may have to use scale mode.

[socratis]

34" ultra wide monitor

That's strange, no?

Not really if you think about it. 16-bit programs (like the one that you're trying to run) don't have the notion of High-Definition. They overfloat? 2^16=65536, aka nowhere near the resolution of a 34" XXXXX*YYYYY mega-monitor. You have to adapt your VM to the expectations of the era that it was created, not the other way around...

[mpack]

aka nowhere near the resolution of a 34" XXXXX*YYYYY mega-monitor.

I have my doubts about that one. Right now, 4K "resolution" is top end, hence an x-coord fits into 12 bits. I think it'll still be a wee while before we overflow a screen width of 65536 pixels (the 16 bit coordinate limitation) on a computer. In fact we may never do, since there's a level of detail you can reach beyond which it's wasted because the eye just can't see it.

The difference between 12bits and 16bits may not sound like much, but it means that screen width has to double four more times before it becomes a problem. That implies a display with 256x as many pixels as currently, and some shocking bandwidth requirements to get frames to that display at 60hz.

[drmtesta]

So do I need to limit the display in VB? XP works fine as does the companion program from the same company. Just this one program has an issue when it goes full screen.

[mpack]

If it's only a single application that gives you trouble then I'm afraid only the authors of that application could tell you why. If that is what you meant that Socratis is very likely correct when he says that the image is just too large compared to what the app was designed to deal with.

[michaln]

For a very long time, screen resolutions bigger than 2048 in either dimension were essentially impossible. It's entirely plausible that some old application can't deal with a bigger screen.

But yeah, only the vendor of the application can really answer that.

[mpack]

For a very long time, screen resolutions bigger than 2048 in either dimension were essentially impossible.

I don't remember that one. Was that a VESA limitation Michal? I know that the old Win16 method of passing coordinates around (LOWORD(lParam),HIWORD(lParam)) is still in use today in Win32.

[michaln]

Not VESA, although a lot of graphics hardware had a 2048-pixel limitation.

Whatever the problem is, the software clearly reacts poorly way before any 16-bit limit is hit (either 65,536 or 32,768). You are right about Windows using 16-bit coordinates, but this isn't Windows falling apart, it's something application specific. Hard to say more without seeing the app.