Windows uses file extensions to deternmine if a file is executable and the type of executable that it is but why does it need different types of executable and what are the technical difference in the way that it is executed. Surely the unix method of file mode permissions and checking the content of the file for the type is a safer and more flexible method as any file can potentially be executed and the problems occuring from incorrect extensions are eliminated. Any thoughts would be much appreciated.

Both COM and EXE are both binary executables files that contain processor instructions. COM files are: * limited in size to 64K * start at 100 hex in memory EXE files are * not limited to 64K * can start anywhere in memory As can be seen COM files are very limited in use. EXE files are almost always uesd today. EXE and COM files usually start out as text files containing keywords for a particular programming language such as Assembler, Basic, C, Pascal, etc. A compiler and linker are used to convert these keywords into a binary executable. BAT files are ordinary text files. They cantain regular DOS commands plus special DOS commands created for use with batch files. Since these are regular text files DOS must read each line one by one when the batch file is run and perform actions based on its interpretation of that line.