virtual-address-space

I've been learning these topics and read many articles and books but they all lack some complementary information and confused me even more. So here, I’d like to explain what I know while I am asking my questions. Hopefully, this topic will be useful for many like me. I'd also like to learn validity of my knowledge and corrections if necessary. Virtual Memory Some articles say “Virtual Memory is some space of Hard Disk which emulates Physical Memory so that we can have more memory than we actually have.”. Some other articles say “Virtual Memory is the combination of Physical Memory (RAM), a

We need to link one of our executables with this flag as it uses lots of memory. But why give one EXE file special treatment. Why not standardize on /LARGEADDRESSAWARE? So the question is: Is there anything wrong with using /LARGEADDRESSAWARE even if you don't need it. Why not use it as standard for all EXE files? Opmet blindly applying the LargeAddressAware flag to your 32bit executable deploys a ticking time bomb ! by setting this flag you are testifying to the OS: yes, my application (and all DLLs being loaded during runtime) can cope with memory addresses up to 4 GB. so don't restrict the

I would like to disable address space layout randomization (ASLR) on my system (Ubuntu Gnu/Linux 2.6.32-41-server), but, if I use sysctl -w kernel.randomize_va_space=0 the change would affect all users on the system, I presume. (Is this true?) How can I limit the effects of disabling ASLR to myself as a user only, or only to the shell session in which I invoke the command to disable? BTW, I see that my system's current (default) setting is sysctl -w kernel.randomize_va_space=0 Why 2 and not 1 or 3? Where can I find documentation about the numerical values of /proc/sys settings, their ranges,

Is there any API for determining the physical address from virtual address in Linux operating system? Kernel and user space work with virtual addresses (also called linear addresses) that are mapped to physical addresses by the memory management hardware. This mapping is defined by page tables, set up by the operating system. DMA devices use bus addresses. On an i386 PC, bus addresses are the same as physical addresses, but other architectures may have special address mapping hardware to convert bus addresses to physical addresses. In Linux, you can use these functions from asm/io.h : virt_to

When executed, program will start running from virtual address 0x80482c0. This address doesn't point to our main() procedure, but to a procedure named _start which is created by the linker. My Google research so far just led me to some (vague) historical speculations like this: There is folklore that 0x08048000 once was STACK_TOP (that is, the stack grew downwards from near 0x08048000 towards 0) on a port of *NIX to i386 that was promulgated by a group from Santa Cruz, California. This was when 128MB of RAM was expensive, and 4GB of RAM was unthinkable. Can anyone confirm/deny this? As Mads