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Hi people. I'm trying to figure out how the memory for screen mode 12h for BIOS screen-set call (ah=00h, int 10h) is organised. It would seem that the first block of memory is a bitmap for whether the pixel is on or off - but how do you change the colour of that pixel? I'm trying to rewrite...

Hi tek people. I have been trying to write a simple operating system for a while and I am stuck on the memory management. The problem is how memory is organized after 1Mb. The first thing that has to be done is enable the A20 line, and I have done that. But what does that actually do? To access...

How do you find out memory size in assembly? I know there are the bios interrupts 11 and 12, but they only work in kb, which isn't very good if you have for example 20M. Also these don't include extended memory. Does anyone have any ideas ?

Assuming that a sector on a floppy disk is 512 bytes long and the floppy is a standard 3.5" disk: - How many sectors are there per head ? - How many heads per cylinder(or track??) ? - How many cylinders on the disk ?

Hi people. I have been working on a boot loader program for a while, and it is almost working fully. I've just hit one problem that occurs after loading a program (off sector 2) in memory. Take a look at the code: assume cs:code code segment org 100h program: jmp start msg1 db 'Boot...

To perform a reboot in DOS, all you need to do is jmp to location FFFFh:0000h. How do you do this ?? I did have some code for this, but I can't remember how to jump to that segment. Can anyone help? Thanks, Adonai.

Hi everyone. I have started some simple graphics routines in assembly for SVGA resolution. The code I have written for a simple line is shown below. I am using an interrupt to set the pixel. However, this is very slow! Does anyone know how to access the graphics memory area directly for SVGA...

Hi everyone. I wish to be able to obtain a handle for a thread whose ID value I know, but I don't know how to do this. For processes, to do the same thing you could use OpenProcess(), but there is no function OpenThread. Does anyone know what I need to do ? Thanks, Adonai. :-)

Hi everyone. I can't quite get my head around this problem. I can get all the process ID values by using the 'EnumProcesses()' function. However, this isn't very helpful to me because the ID values are just hex numbers and change each time you run the same process. Does anyone know how to get...

I have a problem with terminating 2 processes. The program I have wrote so far is as follows: #include "stdafx.h" int APIENTRY WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)...

I have been attempting to write a bootable floppy in assembly and have got this code so far. The problem is that I don't know where the data has got to ?! Can anyone point me in the right direction for finding it ! Thanks, Adonai. PS: the code is here if you want to take a look :) code...

Does anyone know where I can get hold of any network libraries for C. I am using an MS-DOS machine. I have done some network programming in Windows using WinSocks, but now I would like to make just a DOS based routine. Cheers, Adonai.

Hello. I am attempting to write some code to make a screensaver. I have tried to make a fullsize window that covers the whole desktop, but one that does not have a titlebar. So far I have been unsuccessful in my attempts. Can anyone tell me what I need to do to make this full screen window...

I wrote a TSR program for storing keyscan codes in a buffer, but it didn't quite work. Here is relevent code: ;( Start of code extract ) ;......... keycount dw 1 ; Counter keyscan db 100 dup (?) ; Buffer ; Key int replaces interrupt 9 (key press) keyint: cli push ax ; save...

Does anyone know how to access remote sources low-level style in assembly. I think there may be some interrupts for this if you have the right drivers installed, but I don't know what they are. Using the 'IN' and 'OUT' operatives would be a start, but I don't know what the port number(s) are...