On Fri, 20 Sep 2002 [EMAIL PROTECTED] wrote:
>.. How am i suppose to know how the HP8570C does shadowing? It just > does it Well, after paying all the moola to buy such a beast, would think a few more bucks for the hardware manual wouldn't hurt much. But maybe HP doesn't make hardware/software manuals for their equipment like other proprietary systems, ie. apple/sun. Still, that question might prompt another: How would the programmer do shadowing to help the memory-starved program along a bit? Why do shadowing? Because the hardware is too slow, is my guess. And then there is the more detailed matter of directly addressing the video hardware everytime you want to flip a bit or two. And, somewhere in the early install faqs that mention shadowing in linux, why to turn it off, is that linux does a much better job doing its own shadowing. More efficient. Perhaps linux docs will show how it does this shadowing so much better, and it might show how in principle it is done. Is the actual architecture so different? Forgive me, I have no HP to explore, but it would be fun. There is a book, Assembly Language: Step-by-Step, (2nd Ed.) by Jeff Duntemann, publ. Wiley, 2000 It is very easy reading, deals with the basics well. Since I've only begun to use dosemu, I expect to have to check that book out again, because it dealt with the problem of writing to video RAM and even shadowing, I think. >and there's no way to turn it off through >bios setup. So the bios for vectra is significantly different than that of your machine? I have no hp machine to look at. But if I did, I'd want to see where it keeps video data in the first place. The manufacturer of the video chips almost always do publish hardware manuals, otherwise no one would write software for them. The standard video addresses/switches are well-documented. The bios setup program is just software that addresses the settings. Usually there is an address in memory that when referenced, changes state, becomes writable or not it points to another area that is writable. That area could be either video RAM or some other memory. That's as specific as I can get at the moment, but you get the idea. I'd want to know specifically if video hardware on hp is significantly different in some way from any other pc-compatibles. Bet it isn't. It makes no sense there is no hardware switch to turn off shadowing, so now I'm curious what method hp uses. Surely this info would be available to a hardware owner. And if there are no hp-specific publications, perhaps a phone call to one of their engineers that works on video addressing would yield something. Somebody had to decide how things would be done at some point in your machine's history. A direct call might just be the fastest way to get an answer and maybe even a reference or two, or a private privileged (you paid your moneys) online link for users. > I've tried getting graphics to work in dosemu before in the > past but everytime i tried to run a game such as wolf3d the thing went > black which forced me to switch terminal screens and log back in to > kill the dosemu process. Forced how? Did it hang, no response? Going all black might mean just no memory, no pointer to memory, the memory it needs. Wolf3d does have source code available for free. Have you compiled it to work on your system? Somewhere in that code would be the video addressing routines. Compile, run with lots of stderr, study the error messages, find the trouble spot. See how it would be solved in the non-proprietary system. Forgive, all theoretical, you're probably in a hurry to play the darn game. > .. needed to disable video/bios shadowing. This is what most people > seem to suggest when someone asks the question "how do i get graphics > to work" Need a more specific question to get a better answer. There are refs that cover these things, search for "svga programming shadow methods". I tried it, found this to start: http://www.geocities.com/SiliconValley/Park/9784/tut.html 2D Basics, VGA Mode 13h SVGA - vesa, vbe 2 By the way, what kind of video do you have? VESA? Lots of docs on that standard. Find out all the details you can on your video interface, what the range and limits of your monitor/video firmware. > ... but the fonts were screwy since it was using the default terminal > font and I never did figure out how to fix that. But therein lies some secrets. Text on video is done much the same way. Maybe slug through that, find out how it does switch to non-hardware fonts. Map the known. > Oh, I also got QBasic to work too but it > appears to be really slow so i'm afraid even games like wolf3d would > be coming to a halt on this 450 mhz system. It would of course be slow, not comparable to compiled C or assembly code, processed in RAM. Imagine running X with 8 megs free RAM. It would swap on the hardware. Be click and wait. ;) > I was really hoping there was another solution to getting graphics to > work in dosemu without having to really disable video/bios shadowing > in the first place. Not without getting down and dirty, I expect. HP somehow uses its own shadowing algorithms/switches/memory moves. Where and how it does it is documented somewhere or no one could write code for it. Are those routines built into ROM by any chance? Apologies if I'm way off base here. Am new. Will shut up and listen now. Cheers, Pat - To unsubscribe from this list: send the line "unsubscribe linux-msdos" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
