IntSpy is an MS-DOS program able to monitor interrupts generated by another program. It can be specified which interrupts are monitored. If an interrupt occurs, depending on the register contents, a message is written to the console or to a file.
It is possible to selectively monitor all attempts to access files, or to monitor all attempts to access a network, or to monitor all MS-DOS calls made by a program. It is also possible to print all MS-DOS calls, as C subroutine calls.
Download IntSpy, including the source code.
Previously IntSpy has been shareware. Now it is free software.