Important Notice

The pages on this site contain documentation for very old MS-DOS software, purely for historical purposes. If you're looking for up-to-date documentation, particularly for programming, you should not rely on the information found here, as it will be woefully out of date.

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     The format of the system configuration table is as follows:
 
     Bytes       Contents
 
     00h-01h     Length of table in bytes
     02h         System model
     03h         System submodel
     04h         BIOS revision level
     05h         Configuration flags
 
                 Bits     Significance (if set)
 
                 7        DMA channel 3 used
                 6        Slave 8259 present (cascaded IRQ2)
                 5        Real-time clock available
                 4        Keyboard intercept
                          (Int 15h Function 4Fh) available
                 3        Wait for External Event is available
                 2        Extended BIOS data area allocated
                 1        Micro Channel implemented
                 0        Reserved
 
     06h-09h     Reserved
 
     The system model and type bytes are assigned as follows:
 
     Machine                           Model Byte     Submodel Byte
 
     PC                                FFh            ──
     PC/XT (11/08/82 BIOS)             FEh            ──
     PCjr                              FDh            ──
     PC/AT (6/10/85 BIOS)              FCh            00h
     PC/AT (11/15/85 BIOS)             FCh            01h
     PC/XT-286                         FCh            02h
     PS/2 Model 50[Z]                  FCh            04h
     PS/2 Model 60                     FCh            05h
     PC/XT (1/10/86 & 5/9/86 BIOS)     FBh            00h
     PS/2 Model 30                     FAh            00h
     PC Convertible                    F9h            00h
     PS/2 Model 80 (16MHz)             F8h            00h
     PS/2 Model 80 (20MHz)             F8h            01h
     PS/2 Model 70 (20MHz)             F8h            04h
     PS/2 Model 70 (16MHz)             F8h            09h
     PS/2 Model 55                     F8h            0Ch
     PS/2 Model 70 (25MHz)             F8h            0Dh
 
     These bytes should be used with care, as they do not reflect
     alternate processor cards (such as Microsoft MACH 20).
                                    -♦-