Int 31  - Virus - "vacsina" Series - Installation Check (not A Vector!)    [v]


Note:  if one of the Vacsina viruses is resident, the low byte of this
     interrupt still contains the last byte of the INT 30 CP/M JMP
     instruction, but the remaining three bytes are 7Fh 39h followed
     by the Vacsina version number

See Also: INT 21/AX=FFFFh"VIRUS",INT 32"VIRUS"