DOS头结构
typedef struct _IMAGE_DOS_HEADER { // DOS .EXE header
+0h WORD e_magic; // *****DOS可执行文件标记*****
+2h WORD e_cblp; // Bytes on last page of file
+4h WORD e_cp; // Pages in file
+6h WORD e_crlc; // Relocations
+8h WORD e_cparhdr; // Size of header in paragraphs
+0ah WORD e_minalloc; // Minimum extra paragraphs needed
+0ch WORD e_maxalloc; // Maximum extra paragraphs needed
+0eh WORD e_ss; // DOS代码的初始化堆栈SS
+10h WORD e_sp; // DOS代码初始化堆栈指针SP
+12h WORD e_csum; // Checksum
+14h WORD e_ip; // DOS代码初始化指令入口[指针IP]
+16h WORD e_cs; // DOS代码的初始化堆栈入口
+18h WORD e_lfarlc; // File address of relocation table
+1ah WORD e_ovno; // Overlay number
+1ch WORD e_res[4]; // Reserved words
+24h WORD e_oemid; // OEM identifier (for e_oeminfo)
+26h WORD e_oeminfo; // OEM information; e_oemid specific
+29h WORD e_res2[10]; // Reserved words
+3ch LONG e_lfanew; // *****指向PE文件头*****
} IMAGE_DOS_HEADER, *PIMAGE_DOS_HEADER;
原文：http://www.cnblogs.com/zheh/p/4006177.html