在Windows体系统中，windows通过一些结构体来保存windows信息。这些许多就关系到微软未公开的文档。SYSTEM_BASE_INFORMATION结构就是其中的一个。它通过调用ntdll.dll中的ZwQuerySystemInformation函数可以得到这个结构的值。下面是演示代码：
#include "stdafx.h"
#include <conio.h>
#include <windows.h>

typedef LONG NTSTATUS;

typedef enum _SYSTEM_INFORMATION_CLASS
{
 SystemBasicInformat
}SYSTEM_INFORMATION_CLASS;

typedef struct _SYSTEM_BASIC_INFORMATION
{
 ULONG Unknown;       //Always contains zero
 ULONG MaximumIncrement;     //一个时钟的计量单位
 ULONG PhysicalPageSize;     //一个内存页的大小
 ULONG NumberOfPhysicalPages;    //系统管理着多少个页
 ULONG LowestPhysicalPage;     //低端内存页
 ULONG HighestPhysicalPage;    //高端内存页
 ULONG AllocationGranularity;
 ULONG LowestUserAddress;     //地端用户地址
 ULONG HighestUserAddress;     //高端用户地址
 ULONG ActiveProcessors;     //激活的处理器
 UCHAR NumberProcessors;     //有多少个处理器
}SYSTEM_BASIC_INFORMATION,*PSYSTEM_BASIC_INFORMATION;

typedef NTSTATUS (__stdcall *ZWQUERYSYSTEMINFORMATION) (IN SYSTEM_INFORMATION_CLASS SystemInformationClass,
              IN OUT PVOID SystemInformat,
              IN ULONG SystemInformatLength,
              OUT PULONG ReturnLength OPTIONAL);

static ZWQUERYSYSTEMINFORMATION ZwQuerySystemInformation = NULL;

int _tmain(int argc, _TCHAR* argv[])
{
 SYSTEM_BASIC_INFORMATION SysBaseInfo;
 NTSTATUS status;

 if( !(ZwQuerySystemInformation = (ZWQUERYSYSTEMINFORMATION)GetProcAddress(GetModuleHandle("ntdll.dll"),"ZwQuerySystemInformation")))
 {
  printf("GetProcAddress failed");
  return -1;
 }

 status = ZwQuerySystemInformation(SystemBasicInformat,&SysBaseInfo,sizeof(SysBaseInfo),0);
 if(status != NO_ERROR)
 {
  printf("ZwQuerySystemInformation failed");
  return -1;
 }

 printf("MaximumIncrement = %d\n",SysBaseInfo.MaximumIncrement );
 printf("PhysicalPageSize = %d\n",SysBaseInfo.PhysicalPageSize );
 printf("NumberOfPhysicalPages = %d\n",SysBaseInfo.NumberOfPhysicalPages );
 printf("LowestPhysicalPage = %d\n",SysBaseInfo.LowestPhysicalPage );
 printf("HighestPhysicalPage = %d\n",SysBaseInfo.HighestPhysicalPage );
 printf("AllocationGranularity = %d\n",SysBaseInfo.AllocationGranularity );
 printf("LowestUserAddress = %X\n",SysBaseInfo.LowestUserAddress );
 printf("HighestUserAddress = %X\n",SysBaseInfo.HighestUserAddress );
 printf("ActiveProcessors = %d\n",SysBaseInfo.ActiveProcessors );
 printf("NumberProcessors = %d\n",SysBaseInfo.NumberProcessors );
 getch();
 return 0;
}