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Friday, July 14, 2006

ArabOS news 1

Hiiii again :D
Finally I have managed to fix some annoying bugs about the cursor update and the programmable interval timer. I also have added a starter basic keyboard support. It seems clear now how to support DMA, and support devices. I am now being busy in reading about paging and virtual memory. Process management needs memory management. And virtual memory needs a file system. So I will not support VM now, just physical memory. You can visit http://del.icio.us/meemoxp for links about all that. I add each link I see interesting to it.
A quick summary about the OS state:
PIT: working fine.
Terminal: very basic but working fine.
KB: very basic and working fine.
I mean by very basic that the H/W stuff is working and all the remaining features are software stuff.
And by the way, another killer bug was also for using && instead of & !!!
The most of the past weeks was mainly for cleaning the code, setting constants instead of magic values, commenting on code, editing the makefile and well-structuring it, modifying the linker script, and fixing some bugs.
The main problem that you can't count on the code working well for being bug-less, and that you can't count that there is no better way of doing things. You also can't count that you know all features provided by each of the chipsets on the mother board, like APIC etc. You also can't count that you can catch and solve all the exceptions (especially hardware ones) because some may only occur at very rare occasions. Some exceptions once discovered might make you change more than 3 files and change a big structure of the system, especially at this early stage of development.
I am now going for monolithic kernel, not microkernel, and going for stack-swapping for process scheduling, not TSS.

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