INT 2F u - DOS 3.3+ KEYB.COM internal - INSTALLATION CHECK
        AX = AD80h
Return: AL = FFh if installed
            BX = version number (BH = major, BL = minor)
            ES:DI -> internal data (see below)
Notes:  MS-DOS 3.30, PC-DOS 4.01, and MS-DOS 5.00 all report version 1.00.
        undocumented prior to the release of DOS 5.0

Format of KEYB internal data:
Offset  Size    Description
 00h    DWORD   original INT 09
 04h    DWORD   original INT 2F
 08h  6 BYTEs   ???
 0Eh    WORD    flags
 10h    BYTE    ???
 11h    BYTE    ???
 12h  4 BYTEs   ???
 16h  2 BYTEs   country ID letters
 18h    WORD    current code page
---DOS 3.3---
 1Ah    WORD    pointer to first item in list of code page tables???
 1Ch    WORD    pointer to ??? item in list of code page tables
 1Eh  2 BYTEs   ???
 20h    WORD    pointer to key translation data
 22h    WORD    pointer to last item in code page table list (see below)
 24h  9 BYTEs   ???
---DOS 4.01---
 1Ah  2 BYTEs   ???
 1Ch    WORD    pointer to first item in list of code page tables???
 1Eh    WORD    pointer to ??? item in list of code page tables
 20h  2 BYTEs   ???
 22h    WORD    pointer to key translation data
 24h    WORD    pointer to last item in code page table list (see below)
 26h  9 BYTEs   ???

Format of code page table list entries:
Offset  Size    Description
 00h    WORD    pointer to next item, FFFFh = last
 02h    WORD    code page
 04h  2 BYTEs   ???

Format of translation data:
Offset  Size    Description
 00h    WORD    size of data in bytes, including this word
 02h N-2 BYTEs  ???

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