Int 21 Fn 2C00  - Skudo - Installation Check                               [v]

   AX = 2C00h
   CX = 534Bh ('SK')
   DX = 5544h ('UD')
   BX = 4F21h ('O!')

Return: AX = 5349h ('SI') if installed
       CH = version number
       CL = subversion
Program: SKUDO is an antivirus TSR by Jordi Mas