Search found 34 matches

by ehenkes
Thu Aug 20, 2009 10:54 am
Forum: Beginning OS Development
Topic: What is wrong on some PC with this 1st stage BL?
Replies: 12
Views: 22924

Re: What is wrong on some PC with this 1st stage BL?

I found the solution: mov ax, 0x9000 ; set the stack <--- wrong As far as I see, this is in the root dir memory region (14 sectors; from 0x7E00 to 0x9A00) http://www.henkessoft.de/OS_Dev/Bilder/FAT1_FAT2_Root.PNG :shock: mov ax, 0x7C00 ; it works! The open question: Why does this mistake hit only on...
by ehenkes
Thu Aug 20, 2009 10:10 am
Forum: Beginning OS Development
Topic: What is wrong on some PC with this 1st stage BL?
Replies: 12
Views: 22924

Re: What is wrong on some PC with this 1st stage BL?

Can you successfully boot anything else off it? If I exchange my 1st stage BL with your original BL, then it works. I have read the original message again: "Loading Second Stage Bootloader " <-- this comes from mov [bootdevice], dl ; store boot device mov si, msgLoading call print_string Hence, it ...
by ehenkes
Thu Aug 20, 2009 9:53 am
Forum: Beginning OS Development
Topic: What is wrong on some PC with this 1st stage BL?
Replies: 12
Views: 22924

Re: What is wrong on some PC with this 1st stage BL?

This means that either the drive you are using is broken or the bootloader signature is in the wrong place I looked with a hex editor directly at the disk (in the floppy disk device of this PC): 0x55 0xAA at the right place (the same disk boots in other PCs). Looks like this: http://www.henkessoft....
by ehenkes
Thu Aug 20, 2009 8:02 am
Forum: Beginning OS Development
Topic: What is wrong on some PC with this 1st stage BL?
Replies: 12
Views: 22924

Re: What is wrong on some PC with this 1st stage BL?

This one (from 4) PC, which objects to boot process (whereas all the other three boot), tells me that there is "no bootable disk, press ... for reboot". I do not see the error possibility. Bootloading is a complex process, and you never know. BIOS int 0x18: ROM BASIC loader I have taken that from yo...
by ehenkes
Wed Aug 19, 2009 10:57 am
Forum: Beginning OS Development
Topic: What is wrong on some PC with this 1st stage BL?
Replies: 12
Views: 22924

What is wrong on some PC with this 1st stage BL?

To use an own BL is one of the great adventures in OS development, espacially if you want you OS running at all kinds of PC. I rearranged the BL of this demo, because I do not like org 0 and some of the variable names, but now on some modern PCs this BL does not start up: ; boot.asm [Bits 16] org 0x...
by ehenkes
Mon Aug 17, 2009 9:57 am
Forum: Beginning OS Development
Topic: OS Dev Demo11
Replies: 7
Views: 15704

Re: OS Dev Demo11

to include USB booting
AFAIK, This would be a unique selling point. Great tutorial series! Please try to make it -Werror -Wall approved. Release Version of Demo15 could not be compiled error-free in MSVC++ 2008 Express, and a lot of errors appeared. :cry:
by ehenkes
Sun Aug 16, 2009 11:08 pm
Forum: Beginning OS Development
Topic: Questions about the future of the tutorial.
Replies: 11
Views: 22328

Re: Questions about the future of the tutorial.

Great! Thank you. :D
by ehenkes
Sun Aug 16, 2009 10:53 pm
Forum: News Discussion
Topic: something that we lost...
Replies: 8
Views: 52846

Re: something that we lost...

James Molloy's "heap" tutorial is quite good: http://www.jamesmolloy.co.uk/tutorial_h ... 0Heap.html
by ehenkes
Sun Aug 16, 2009 7:22 pm
Forum: Beginning OS Development
Topic: Chapter 20, Demo 15, how to write a sector to floppy disk?
Replies: 6
Views: 15126

Re: Chapter 20, Demo 15, how to write a sector to floppy disk?

http://www.dynacube.net/source/index.html
There you can find the interesting module floppy.h/floppy.c
Nice educational OS from India.
by ehenkes
Sun Aug 16, 2009 1:50 pm
Forum: Beginning OS Development
Topic: Demo 15 Problem
Replies: 25
Views: 51397

Re: Demo 15 Problem

I'm having a problem with the code in Demo 15
OS code should run with -Werror and -Wall. Otherwise, there are a lot of hidden problems. 8)
by ehenkes
Sun Aug 16, 2009 10:27 am
Forum: Beginning OS Development
Topic: Questions about the future of the tutorial.
Replies: 11
Views: 22328

Re: Questions about the future of the tutorial.

I would propose to read and write to USB sticks, because floppy discs are not widespread nowadays and will not be rampant in the future. :D
by ehenkes
Sun Aug 16, 2009 10:11 am
Forum: Beginning OS Development
Topic: Chapter 20, Demo 15, how to write a sector to floppy disk?
Replies: 6
Views: 15126

Re: Chapter 20, Demo 15, how to write a sector to floppy disk?

you should use FLPY_SECTORS_PER_TRACK as the parameter Yes, that's correct. In the beginning, I wanted to write a function void flpydsk_write_sector_imp(unsigned char head, unsigned char track, unsigned char sector, unsigned char num_of_sectors) It works wonderfully with num_of_sectors less than 18...
by ehenkes
Fri Aug 14, 2009 8:07 pm
Forum: Beginning OS Development
Topic: Chapter 20, Demo 15, how to write a sector to floppy disk?
Replies: 6
Views: 15126

Re: Chapter 20, Demo 15, how to write a sector to floppy disk?

current code: // write a sector void flpydsk_write_sector_imp(unsigned char head, unsigned char track, unsigned char sector) { ULONG st0, cyl; flpydsk_dma_write(); // set the DMA for write transfer flpydsk_send_command( FDC_CMD_WRITE_SECT | FDC_CMD_EXT_MULTITRACK | FDC_CMD_EXT_DENSITY ); // write a ...
by ehenkes
Fri Aug 14, 2009 7:58 pm
Forum: Beginning OS Development
Topic: Chapter 20, Demo 15, how to write a sector to floppy disk?
Replies: 6
Views: 15126

Re: Chapter 20, Demo 15, how to write a sector to floppy disk?

This is nonsense:

Code: Select all

flpydsk_send_command(( ( sector + 1 ) >= FLPY_SECTORS_PER_TRACK ) ? FLPY_SECTORS_PER_TRACK : sector + 1 ); 
better:

Code: Select all

flpydsk_send_command( 18 );