INT 69 - 10NET v5.0 - SYSSVC.COM - SIGNAL SYSTEM ERROR
        AH = FFh
Return: never???
Notes:  displays "System Error" message and register dump, then halts system
        INT 69 is the default, and may be set to any interrupt from 60h-7Fh;
          the signature "SYSV" immediately before the interrupt handler serves
          as the installation check
SeeAlso: AX=4001h,AH=49h

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