Maybe unrelated, but this made me think of "The Rise of 'Worse is Better'": (NOTE: In this context, "PC" means "Program Counter".) "... The PC loser-ing probl

Maybe unrelated, but this made me think of "The Rise of 'Worse is Better'": (NOTE: In this context, "PC" means "Program Counter".) "... The PC loser-ing problem occurs when a user program invokes a system routine to perform a lengthy operation that might have significant state, such as IO buffers. If an interrupt occurs during the operation, the state of the user program must be saved. Because the invocation of the system routine is usually a single instruction, the PC of the user program does not adequately capture the state of the process. The system routine must either back out or press forward. The right thing is to back out and restore the user program PC to the instruction that invoked the system routine so that resumption of the user program after the interrupt, for example, re-enters the system routine. ..." http://www.jwz.org/doc/worse-is-better.html http://www.jwz.org/doc/worse-is-better.html