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Annotation of os232sdk/toolkt20/c/samples/vmm/descrip.txt, revision 1.1

1.1     ! root        1: VMM Description
        !             2: ---------------
        !             3: 
        !             4: This application demonstrates some of the basic components
        !             5: of the new memory API for OS/2 2.0. Using the
        !             6: system-defined page size of 4096 bytes, this application
        !             7: gives the developer a visual representation of what is
        !             8: happening inside the machine when they use the API's.
        !             9: 
        !            10: It is written with the following objective:
        !            11: 
        !            12: 
        !            13:     To demonstrate the use of the basic memory management
        !            14:     API's available to developers in OS/2 2.0. This is done
        !            15:     with the use of visual aid in the form of pages on the
        !            16:     screen with their attributes included.
        !            17: 
        !            18: To use the VMM application, the user must issue the "VMM"
        !            19: command at the screen prompt.
        !            20: 
        !            21: The user is presented with a blank screen, with the
        !            22: exception of the menus. To use VMM, the user must first
        !            23: select "Allocate" from the VMM menu. This will allow the
        !            24: user to allocate "n" bytes of memory (decimal) and set
        !            25: the appropriate attributes for the memory that they wish
        !            26: to allocate. Each allocation is rounded up (by the
        !            27: system) to the next page size (4096 bytes per page), and
        !            28: that many pages are allocated to the user.
        !            29: 
        !            30: After allocating memory, the user can commit (if not
        !            31: already committed) or decommit the memory using the "Set
        !            32: Memory Attributes" menu selection. Pages that are
        !            33: displayed in green are committed, while those displayed in
        !            34: red are not.
        !            35: 
        !            36: Other attributes (such as read, write, execute, and guard
        !            37: page) may also be set for committed pages using the "Set
        !            38: Memory Attributes" menu selection.
        !            39: 
        !            40: For committed pages with the write capability set, the
        !            41: user may put text into the memory bytes using the "Write
        !            42: Memory" menu selection. The user simply enters the
        !            43: address (hexadecimal) and the text they wish to write
        !            44: into memory.
        !            45: 
        !            46: To read the data stored in a particular memory location,
        !            47: use the "Read" command and enter the corresponding address
        !            48: into the dialog box entry field. Data will be read from
        !            49: the memory location specified up to the first null
        !            50: character. The data is displayed in a dialog box.
        !            51: 
        !            52: To free up memory, the user needs to choose "Free Memory"
        !            53: from the menu. The address of a base page is the only
        !            54: address that is allowed to be freed. Any freeing of a
        !            55: non-base address will result in an "invalid address"
        !            56: error message.
        !            57: 
        !            58: APIs FEATURED:
        !            59: 
        !            60: DosAllocMem
        !            61: DosError
        !            62: DosFreeMem
        !            63: DosQueryMem
        !            64: DosSetExceptionHandler
        !            65: DosSetMem

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