How do one generate a .SYS file ?

[anuragmathur]

Please, tell me about , how can one compile or assemble a file to a .SYS extension file (like himem.sys) from a program in C or assembly language on the MS-DOS or WIN9x/NT/2k. What are these files? How can they be usefull for writing a big application.

 

[rknalla]

Usually .sys files are plain binary files(ie executable files with no header data and relocation tables). They are used for driver programs or ISRs. They can be generated bya any assembler. I use the assembler NASM. The syntax for generating a .sys file is : nasm progname.asm -f bin -o progname.sys

 

[AmkG]

An older method is by using the exe2bin program which used to be included with DOS. Note that SYS files are typically one 16-bit segment. Compile and link into exe, then run it through exe2bin.

If you don't have exe2bin, a short debug script would do:

N file.sys
W
Q

To use, do this:
debug file.exe <debug.scr

&quot;Information has a tendency to be free. Which means someone will always tell you something you don't want to know.&quot;