Magnum One/Magnum One (Mid-American Digital) (Disc Manufacturing).iso/d27/autoc20b.arc/MENUCTL.DOC

Text File | 1991-04-10 | 6KB | 118 lines

                      MENU.CTL - Device Driver

  Description:
    Although Menu.Ctl was written to work directly with AutoCon, it is
    a separate entity, and it can function indelpendently of AutoCon.
    I will give enough information in this document to allow you to
    use it independently, though I don't recommend doing so (sort of a
    "Don't try this at home" warning).

    Menu.Ctl works by taking over control of the processing of the
    CONFIG.SYS file.  It allows you to selectively disable various
    groups of CONFIG.SYS commands.  You tell Menu.Ctl which groups you
    want to control by statements in the CONFIG.SYS file.  The control
    statements are defined below.  The part of the control statements
    enclosed in [] are optional sub controls.

    I don't have DOS 4, but reports are that the device driver
    XMAEM.SYS is processed out of normal sequence, therfore Menu.Ctl
    can't control it.  Only one control statement (DEVICE=XMAMEM.SYS)
    relateing to XMAEM.SYS is allowed per CONFIG.SYS file.  In other
    words only put one statement in one default configuration.  If
    there are two XMAEM.SYS statements in the CONFIG.SYS file, I
    assume that it will not work properly.

    You should also note that any changes made during the boot process
    have no  effect on the actual contents of the CONFIG.SYS file.
    When a device driver is activated the first time, DOS has not made
    enough of itself functional to do "real" file activity.  This
    driver simply works on memory contents.

  Disabling:
    DOS 4.0 introduced a "REMARK" capability into CONFIG.SYS files.
    Menu.Ctl uses this capability to disable the unwanted CONFIG.SYS
    commands.  It replaces all disabled commands with remark
    statements.  In DOSes before 4.0, there is no convenient remark
    statement, so I had to find another way to disable commands.
    While I was creating Menu.Ctl, I noticed that the "BREAK=OFF"
    CONFIG.SYS command was processed with nothing visible on the
    screen.  So I adopted the technique of disabling commands by
    replacing them with "BREAK=OFF" commands.  This technique works
    well, but there are two slight problems with it.

    First, some of the commands I need to disable have a smaller
    memory image than the "BREAK" command.  I found that none of those
    commands have a problem if you add something to the end of the
    line to make it longer.  Below is the way that I lengthen the
    problem commands (I add an *, but any character should work):

      LASTDRIVE=M: *
      BUFFERS=10 *
      FILES=40 *

    Second, if you need to have "BREAK=ON" then you will have to put
    the command in the AUTOEXEC.BAT fields.  I don't know anyone who
    uses this statement, but I'm sure someone does.

  Unrecognized Commands:
    If there is not enough room to convert a command to "BREAK=OFF"
    then AutoCon will make it an "Unrecognized" command.  There is no
    problem with this technique, but it will lead to a lot of
    "Unrecognized command in CONFIG.SYS"  statements showing up on the
    screen during the boot process.



                         CONTROL STATEMENTS

  DEVICE=MENU.CTL [Mx Tx "Text]
    This line gets inserted in the CONFIG.SYS file just ahead of the
    first group of commands that you wish to be able to disable.  The
    x in [Tx] is the seconds MENU.CTL will pause waiting for a
    keystroke before selecting the default configuration.  x defaults
    to zero.  The x in [Mx] is the default menu number (1-8) that will
    be selected as the default configuration.  NOTE: AutoCon always
    writes the CONFIG.SYS file so that the default is Menu 1, so you
    will never see the [Mx] in a CONFIG.SYS file created by AutoCon.
    The Text in ["Text] will be the first menu title shown.  All text
    following the " will be considered part of the title, so it must
    be the last parameter on the line.  You can specify the first
    title this way, or by using the MTITLE command defined below.
    AutoCon uses MTITLE for all Menu titles for my convenience.

  DEVICE=MTITLE [Text]
    The Text in [Text] will be shown as a Menu title on the screen
    when you are making a configuration selection.  Each MTITLE
    command will create a new Menu selection (up to 8).  The
    CONFIG.SYS commands between MTITLE commands will become the
    configuration choice after selection.

  DEVICE=MENUEND
    There is no way for a device driver to know where the end of the
    CONFIG.SYS file is in memory, so this control statement lets
    Menu.Ctl know where the end is.  This statement must be in the
    CONFIG.SYS file in order for it to work properly.


                  BATCH FILE PROCESSING (MENUNUM.COM)

  MENUNUM.COM:
    Menu.Ctl leaves about 180 bytes of itself in memory when it runs.
    MENUNUM.COM is able to communicate with this resident portion.  It
    uses the information in Menu.Ctl to set the errorlevel to the menu
    number chosen during the boot process.  If Menu.Ctl can't be
    found, the errorlevel will be set to 0.  If all menu choices were
    disabled (Menu.Ctl allows the disabling of all CONFIG.SYS
    commands), the MENUNUM will set the errorlevel to 255 (FF hex).

    If you look at the Autoexec.Bat file created by AutoCon in the
    Menu mode, the first thing you will see is MENUNUM.COM.  Following
    this you will see several "IF ERRORLEVEL" statements.  These if
    statements allow the CONFIG.SYS menu choice to be related to the
    AUTOEXEC.BAT menu choices.

    Thus all you need to write your own Boot Menu is Menu.Ctl and
    MenuNum.Com.  A little study of the CONFIG.SYS and AUTOEXEC.BAT
    menu mode files written by AutoCon will give you all of the
    examples you need.