For more information see the following topics:

~INT 15,0~ Turn cassette motor on (PC,PCjr only)

~INT 15,1~ Turn cassette motor off (PC,PCjr only)

~INT 15,2~ Read blocks from cassette (PC,PCjr only)

~INT 15,3~ Write blocks to cassette (PC,PCjr only)

~INT 15,F~ PS/2 format periodic interrupt (PS/2 only)

~INT 15,20~ PRINT.COM Critical region flag (undocumented DOS 3.x+)

~INT 15,21~ PS/2 power on self test (PS/2 except 30)

~INT 15,40~ Read / modify profiles (convertible only)

~INT 15,41~ Wait on external event (convertible only)

~INT 15,42~ Request system power off (convertible only)

~INT 15,43~ Read system status (convertible only)

~INT 15,44~ (De)activate internal modem power (convertible)

~INT 15,4F~ Keyboard intercept (BIOS date specific)

~INT 15,80~ Device open

~INT 15,81~ Device close

~INT 15,82~ Program termination

~INT 15,83~ Event wait

~INT 15,84~ Joy-Stick support

~INT 15,85~ System request key pressed

~INT 15,86~ Elapsed time wait (AT and after)

~INT 15,87~ Move block to/from extended memory

~INT 15,88~ Extended memory size determination

~INT 15,89~ Switch processor to protected mode

~INT 15,90~ Device busy

~INT 15,91~ Interrupt complete

~INT 15,C0~ Return system configuration parameters (PS/2 only)

~INT 15,C1~ Return extended BIOS data address (PS/2 only)

~INT 15,C2~ Pointing device BIOS interface (PS/2 only)

~INT 15,C3~ Enable/Disable watchdog timer

~INT 15,C4~ Programmable option select

- CF is set and AX is left unchanged if a function requested in AH

isn't supported

- some Tandy BIOS's fail to restore interrupts on return from INT 15