What does VirtualAlloc do?

The VirtualAlloc function can be used to reserve an Address Windowing Extensions (AWE) region of memory within the virtual address space of a specified process. This region of memory can then be used to map physical pages into and out of virtual memory as required by the application.

Does malloc call VirtualAlloc?

The malloc implementation of Visual C++ relies on VirtualAlloc to acquire memory from OS.

What is virtual allocation?

A virtual file allocation table (VFAT) is an extension to the file allocation table (FAT) from Windows 95 and onward for creating, storing and managing files with long names. VFAT enables a hard disk drive to store files with names that are more than eight characters long.

What is Mem_commit?

MEM_COMMIT actually commits (or binds depending on. your view) physical memory to previously reserved memory. So when looking at. available VIRTUAL memory you will see that decrease with a reserve even. though no actual physical memory is used.

Is Heapalloc thread safe?

The HEAP_NO_SERIALIZE value can, therefore, be safely used only in the following situations: The process has only one thread. The process has multiple threads, but only one thread calls the heap functions for a specific heap.

What is NtAllocateVirtualMemory?

NtAllocateVirtualMemory can commit an already committed page. This means that you can commit a range of pages, regardless of whether they have already been committed, and the function will not fail.

Does virtual memory increase performance?

Virtual memory, also known as the swap file, uses part of your hard drive to effectively expand your RAM, allowing you to run more programs than it could otherwise handle. But a hard drive is much slower than RAM, so it can really hurt performance. RAM is faster than storage, and you have much less of it.

What is the difference between virtual and physical memory?

The main difference between physical and virtual memory is that the physical memory refers to the actual RAM of the system attached to the motherboard, but the virtual memory is a memory management technique that allows the users to execute programs larger than the actual physical memory.

What is heap Alloc?

Remarks. If the HeapAlloc function succeeds, it allocates at least the amount of memory requested. To allocate memory from the process’s default heap, use HeapAlloc with the handle returned by the GetProcessHeap function. To free a block of memory allocated by HeapAlloc, use the HeapFree function.

What is heap contention?

Whenever two threads try to access the heap simultaneously, one thread is blocked until the other thread’s request is finished. For many applications, this situation rarely occurs and the performance impact of the heap’s locking mechanism is negligible.

What is Userland hooking?

alter the normal code execution of Windows APIs by injecting hooks. This technique is often used to change the behavior of well known Windows APIs. This practice is implemented in a set of programs and code that allows a permanent, consistent or undetectable presence in a previously attacked system.

What is Ntopenprocess?

ObjectAttributes. [in] A pointer to an OBJECT_ATTRIBUTES structure that specifies the attributes to apply to the process object handle. In Windows Vista and later versions of Windows, the ObjectName field of this structure must be set to NULL.

What can the VirtualAlloc function be used for?

The VirtualAlloc function can be used to reserve an Address Windowing Extensions (AWE) region of memory within the virtual address space of a specified process. This region of memory can then be used to map physical pages into and out of virtual memory as required by the application.

Can you see the Revolution of the planets from all angles?

With this simulator you will see the revolution of the planets from all angles and their alignment.

How does VirtualAlloc reserve a block of pages?

You can use VirtualAlloc to reserve a block of pages and then make additional calls to VirtualAlloc to commit individual pages from the reserved block. This enables a process to reserve a range of its virtual address space without consuming physical storage until it is needed.

What’s the difference between VirtualAlloc and RING0?

The VirtualAlloc function basically invokes ZwAllocateVirtualMemory that in turn does a quick syscall to ring0 to relegate further processing to the kernel memory manager. It is also the fastest method to reserve/allocate block of new memory from all available in the user mode.