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Thread: sys files

  1. #1
    Senior Member
    Join Date
    Jun 2004

    sys files

    Hi, I was wornding if any one could point me in the right direction for programing system files. The reason I am interested in this is because I was just wornding when they are called how/what runs them. I know the systme runs them but if i make a batch file and name it .sys if i try to run it I would get a message asking me what I want to use to run the file why is that, why dosen't the system try to run it an crash.

  2. #2
    Senior Member
    Join Date
    Jul 2002

    "Traditionally" (in DOS and Win 3.x era) MS had actually 3 types (I think) of .SYS files.

    The first one is, a special executable file that loads the kernel/OS. There are only 2 files (I think) belongs to this type: IO.SYS and MSDOS.SYS.

    Then I guess the most famous one is a text file (user-readable/editable) that contains the "instructions" to load important OS drivers. There are only 1 file (I think) in this type: CONFIG.SYS.

    The last one is a driver, which is normally specified in CONFIG.SYS to be loaded as part of system startup. There are many files in this type such as ANSI.SYS, HIMEM.SYS, KEYBOARD.SYS, etc. You can find some drivers in newer Windows OS have .SYS extension.

    I see sec_ware subscribed to this thread. He can point you better the right direction for "programming system files" (which I think you meant the 3rd type [drivers]).

    Peace always,
    Always listen to experts. They\'ll tell you what can\'t be done and why. Then go and do it. -- Robert Heinlein
    I\'m basically a very lazy person who likes to get credit for things other people actually do. -- Linus Torvalds

  3. #3
    Just Another Geek
    Join Date
    Jul 2002
    Rotterdam, Netherlands
    I could point you to a more specific location if you tell us what OS?

    For starters I'm assuming Windows:

    MicroSoft Developers Network

    Shell Basics
    Oliver's Law:
    Experience is something you don't get until just after you need it.

  4. #4
    Senior Member
    Join Date
    Jun 2004
    Thanks for the Info and sorry about not saying what win version i am using winxp.

  5. #5
    Senior Member
    Join Date
    Mar 2004

    Those sys-files indeed are device drivers. You cannot execute them,
    rather they are "executed" by the system (they are
    loadable kernel-mode modules). If you want to know, which ones
    are loaded, check your "device manager" (also activate "Show hidden
    devices" in the view-menu) or check your registry
    For example, the file c:\windows\system32\drivers\IPSec.sys is
    responsible for the IPSec functionality.

    Nowadays, the WDM[1] is mostly used. As developer, you could use
    the DDK[2]. I like the multipart-introduction at codeguru[3] or the


    [1] http://msdn.microsoft.com/library/de...6f32be.xml.asp
    [2] http://www.microsoft.com/whdc/devtools/ddk/default.mspx
    [3] http://www.thecodeproject.com/system/driverdev.asp
    [4] http://www.thecodeproject.com/system...evelopment.asp
    If the only tool you have is a hammer, you tend to see every problem as a nail.
    (Abraham Maslow, Psychologist, 1908-70)

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