maximum memory which malloc can allocate

I was trying to figure out how much memory I can malloc to maximum extent on my machine (1 Gb RAM 160 Gb HD Windows platform).

I read that the maximum memory malloc can allocate is limited to physical memory (on heap).

Also when a program exceeds consumption of memory to a certain level, the computer stops working because other applications do not get enough memory that they require.

So to confirm, I wrote a small program in C:

int main(){  
    int *p;
    while(1){
        p=(int *)malloc(4);
        if(!p)break;
    }   
}

I was hoping that there would be a time when memory allocation would fail and the loop would break, but my computer hung as it was an infinite loop.

I waited for about an hour and finally I had to force shut down my computer.

Some questions:

• Does malloc allocate memory from HD also?
• What was the reason for above behaviour?
• Why didn't loop break at any point of time?
• Why wasn't there any allocation failure?