32bit-64bit

I have a very fundamental question relating to 32 bit memory addresses. My understanding is that 2^32 is the maximum number of possible memory addresses on a 32 bit system. Where I am confused is how we go from this number to the alleged 4GB limit. In my research I have seen some people do this: 2^32 = 4,294,967,296 bytes 4,294,967,296 / (1,024 * 1,024) = ~4 GB First, where does this (1,024 * 1,024) come from? Second, correct me if I am wrong, but 4,294,967,296 is labeled as bytes because a byte is the smallest unit of storage space that can be addressed in RAM. Since we're limited to 2^32

I have a piece of code that runs 2x faster on windows than on linux. Here are the times I measured: g++ -Ofast -march=native -m64 29.1123 g++ -Ofast -march=native 29.0497 clang++ -Ofast -march=native 28.9192 visual studio 2013 Debug 32b 13.8802 visual studio 2013 Release 32b 12.5569 It really seems to be too huge a difference. Here is the code: #include <iostream> #include <map> #include <chrono> static std::size_t Count = 1000; static std::size_t MaxNum = 50000000; bool IsPrime(std::size_t num) { for (std::size_t i = 2; i < num; i++) { if (num % i == 0) return false; } return true; } int main

Porting code from 32bit to 64bit. Lots of places with int len = strlen(pstr); These all generate warnings now because strlen() returns size_t which is 64bit and int is still 32bit. So I've been replacing them with size_t len = strlen(pstr); But I just realized that this is not safe, as size_t is unsigned and it can be treated as signed by the code (I actually ran into one case where it caused a problem, thank you, unit tests!). Blindly casting strlen return to (int) feels dirty. Or maybe it shouldn't? So the question is: is there an elegant solution for this? I probably have a thousand lines

I'm compiling and running the following program in 32 and 64 bit platforms: int main() { double y = 8.34214e08; double z = 1.25823e45; return y * z == 8.34214e08 * 1.25823e45; } While in 64bit the result is the expected (the values are the same and the exit code is non-zero) in 32bit seems there is a little difference between the value calculated at compile time, the right hand side of the comparison, and the left side computed at runtime. Is this a bug in the compiler or there is a logical explanation? EDIT: this is different from Why comparing double and float leads to unexpected result?

We have a project that compiles to a 32-bit COM DLL and to a 64-bit COM DLL (the same one from my earlier question ). When I register both on my Windows 7 machine, both register successfully. When I register both on a Windows Server 2003 machine, both register successfully. But when I try to register the DLLs on a Windows Server 2008 R2 standard SP1 machine, the 64-bit DLL registers successfully, but the 32-bit DLL fails with the message (sic): The module ""%1"" may not compatible with the version of Windows that you're running. Check if the module is compatible with an x86 (32-bit) or x64 (64

I want to change Enable32BitAppOnWin64 property using C#. I know that the way of interacting with IIS 6 and IIS 7 are different. but I need the solution for both versions. There are a few differences in programmatically managing IIS 6 and IIS 7. IIS 6 is programmatically managed using the DirectoryEntry class and the metabase database API. IIS 7 is managed using the Microsoft.Web.Administration assembly and the ServerManager class. Furthermore IIS 6 is not able to run both 64 bit and 32 bit worker processes at the same time (see this MSDN BLOG ). So setting Enable32BitAppOnWin64 to true for

I have my machine and IDE with following configuration Product Version: NetBeans IDE 7.2 (Build 201207171143) Java: 1.7.0_07; Java HotSpot(TM) 64-Bit Server VM 23.3-b01 System: Windows 7 version 6.1 running on amd64; Cp1252; en_US (nb) The JavaFx bundle (.exe) created during build is of 64 bit. My users are in 32 bit machine so I need to create bundles in 32 bit. Is there any way I can create 32 bit exe files using my machine Tried downloding 32 bit JDK and pointed the same in the project properties but i am not sure if the exe created in 32 bit or not because in task manager the application

In C++ there are predefined macros: #if defined(_M_X64) || defined(__amd64__) // Building for 64bit target const unsigned long MaxGulpSize = 1048576 * 128;// megabyte = 1048576; const unsigned long MaxRecsCopy = 1048576 * 16; #else const unsigned long MaxGulpSize = 1048576 * 8;// megabyte = 1048576; const unsigned long MaxRecsCopy = 1048576; #endif Which allows me to set constants to control the amount of memory that will be used. Of course I can define a preprocessor variable verbatim: #define Is64bit 1 using System; using System.Collections.Generic; -later- #if Is64bit // Building for 64bit