Loader com and exe files (ESP on the assembler)

Features:
- The name of the loader and the name of the downloaded file is specified on the command line;
- Types of executable files com, exe;
- Returns an error code executable program;
The first paragraph of the terms of reference - this job named loader and a downloadable file on the command line. As you know, many operating systems it is possible to start the program with some parameters on the command line, altering the program. And in this sense, DOS operating system is no exception.
The next item is a technical specification types of executable files com, exe. As you know, when you start each process is allocated memory block 2: for the environment and for the program code. Depending on the type com or exe memory allocation strategy for the code is different. To com programs always distinguished the largest free RAM section. For information about the program exe required memory in a special file header and distributed in a few steps. If the remaining free memory a little, and after starting the com file is almost always the case, before starting a child process the parent process must shrink themselves.
The last paragraph of the terms of reference - the program returns an error code executable program. These parameters are often very informative, since they can be used to easily determine the cause of the problem and possible ways to fix it.