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Creating another DOS clone.

Posted: Mon Sep 11, 2006 8:26 pm
by santellan17585
I am looking to create a DOS clone in order to get the hang of OS development. Any advice?

Posted: Tue Sep 12, 2006 1:31 am
by prajwal
Wherther it is DOS, Linux, .... some X OS..... There are certain basic (fundemental) functionalities that a OS should provide....

Assuming u'll try (more adventerous than real mode) 32 bit Protected Mode OS
these are the basic lower level layers which the OS should consists of:-

1. Setting Up GDT (LDT if required), and entering into Protected Mode
2. Interrupt Handling
3. Paging (Mem Management)
4. Process Scheduling
5. Device Drive (first usually for floppy so that u can start working on File System)
6. File System
7. Executable Loading (Support for some exe formats like a.out, ELF, .... or your own)

If this much is done then you can start thiinking to make your OS similar to Linux./ DOS or Something New :)

Posted: Tue Sep 12, 2006 3:39 pm
by Dex
Yes study my 2k Dos clone "MiniDOS"
http://board.flatassembler.net/topic.ph ... sc&start=0
It comes with fully commented fasm source code.

Posted: Tue Sep 12, 2006 10:41 pm
by santellan17585
later, i would like to make a gui for this DOS clone. is this possible, and if so, could i simply impliment something like a batch file in order to get the gui started, kinda like how autoexec.bat in MS-DOS starts the desired processes at startup?

Posted: Tue Sep 12, 2006 10:46 pm
by santellan17585
oh, and btw, if i do take the approach of a linux based OS, is there a way to do that as well with it?

Posted: Wed Sep 13, 2006 8:56 pm
by SpooK
Yes, I suggest taking a look at the Linux 1.1 sources, and possibly Andrew Tanenbaum's MINIX. Version 2 of MINIX comes with the latest "Operating Systems: Design and Implementation" book of his. Version 3 of MINIX can be found HERE. Happy hunting ;)

PS: Prepare to digist mass amounts of vitamin GCC :P

Re: Creating another DOS clone.

Posted: Wed Sep 13, 2006 10:15 pm
by Dex
santellan17585 wrote: Any advice?
Yes!, you will get better response's, if you say thanks, to the people that help you.

Re: Creating another DOS clone.

Posted: Thu Sep 14, 2006 1:07 am
by SpooK
Dex wrote:
santellan17585 wrote: Any advice?
Yes!, you will get better response's, if you say thanks, to the people that help you.
This is mostly true, as most people tend to be emotional types and need positive reinforcement... which usually requires a "Thanks"... or some money :P

"Thanks" and "my friend" tend to be a little annoying after some time. As long as you don't explicitly disrespect me and help the problem solving process by following-up (i.e. "*this* idea/code/reply helped solve my problem"), I'll probably help you. Put "my friend" anywhere in a post or develop a habit of abandoning posts without stating which reply helped (in a multi-response thread, of course)... and I will definitely ignore you in the future ;)