Other than malloc/free does a program need the OS to provide anything else?

Question

I\'m working on designing the kernel (which I\'m going to actually call the \"core\" just to be different, but its basically the same) for an OS I\'m working on. The specifics o

Answer 1

Danger Danger!! If your even considering attempting kernel development, you should be very aware of the cost of your resources and their relatively limited availability...

One thing about recursion, is that it's very, expensive (at least in kernel land), you're not going to see many functions written to simply continue unabaided, or else your kernel will panic.

To underscore my point here, (at stackoverflow.com heh), check out this post from the NT Debugging blog about kernel stack overflow's, specificially,

· On x86-based platforms, the kernel-mode stack is 12K.

· On x64-based platforms, the kernel-mode stack is 24K. (x64-based platforms include systems with processors using the AMD64 architecture and processors using the Intel EM64T architecture).

· On Itanium-based platforms, the kernel-mode stack is 32K with a 32K backing store.

That's really, not a whole lot;

The Usual Suspects

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1. Using the stack liberally.

2. Calling functions recursively.

If you read over the blog a bit, you will see how hard kernel development can be with a rather unique set of issues. You're theory class was not wrong, it was simply, simple. ;)

To go from theory -> kernel development is about as significant of a context switch as is possible (perhaps save some hypervisor interaction in the mix!!).

Anyhow, never assume, validate and test your expectations.