Int 27H

1 and higher

TERMINATE AND STAY RESIDENT

• DX = number of bytes to keep resident (max FFF0h)
  • CS = segment of PSP

never

this is an obsolete call

Function not supported for Win16 applications in protected mode

INT 22, INT 23, and INT 24 are restored from the PSP

does not close any open files

the minimum number of bytes which will remain resident is 110h for DOS 2.x and 60h for DOS 3.0+; there is no minimum for DOS 1.x, which implements this service in COMMAND.COM rather than the DOS kernel

INT 21/AH=31h

Text based on Ralf Brown Interrupt List Release 61