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hey i just read something and i was wondering, is MMURTL DOS dependent?? if anyone has the book or used it, do you already need DOS to run MMURTL?? cause i was reading about int 21 in MMURTL ? hopefully it just recreates int 21

imho i found that book completely useless.
i bought it from Amazon.com about 3 weeks ago. I read the entire thing in about 2 weeks time and still feel it is useless.
I dont think it is completely dependant on DOS.
Although you can run it from DOS or boot it up if i remember correctly

If it needs DOS just incoporatie FreeDOS in your OS just make a FreeDOS image...edit it's autoexec.bat file to load your OS and there ( that's just in theory...it might be more complicated )

No, it does not require DOS to run, but it does assume that you are developing it from DOS, and can be launched from DOS IIRC. It implements it's own system calls through int 21; I think he'd meant it to be partially DOS compatible, originally.

As for the value of the book, while it clearly isn't a standalone guide to OS design or theory, I wouldn't quite call it useless. He does explain, with working code examples, a lot of low-level issues such as accessing the DMA controller for the floppy drive, and he gives considerable detail on implementing a FAT16 file system. It is also the only book that I've seen which really givens a detailed explanation of writing a boot sector (there are many tutorials on line that do as well, though). His writing style is definitely lacking, however.

In the end, the author is simply chronicling his own experiences at implementation; I would look at it as a sort of OS designer's blog with delusions of grandeur. It makes for a decent supplement, but only if you have another good basic text already.

My theory is possible...reactos loads FreeDOS before booting itself...

Not necessarily. It has two loaders: one which runs from DOS, and one which runs from a boot sector.