Re: Exception Handling

[rav@goanna.cs.rmit.edu.au (Robin Vowels)]

	Fritz@Peacham.com (Fritz Schneider) writes:

	>Bob Halpern <wumpus@ix.netcom.com> wrote:
	>>Robin Vowels wrote:
	>>>         >|> Where did the concept of exception handling originate ? For example,
	>>>         >|> which languages were first to support this, or which papers first
	>>>         >|> proposed exception handling ?
	>>> 
	>>> The IBM System 360 (c. 1965) had an interrupt system that could
	>>> trap a range of computational conditions (division by
	>>
	>>There was hardware and software for exception handling that predated the
	>>360.

	>The IBM 709 (a vacuum tube machine) introduced the concept of data
	>channels (now called DMA) in a commercial product ca. 1957. This
	>included interruptions, referred to in that architecture as traps. The
	>current instruction address was stored in a fixed location and control
	>was given to the channel trap routine which stored the registers and
	>processed the interruption. The instruction set included the TTR (TRAP
	>TRANSFER) instruction used to return from interruptions. It could not
	>be trapped, so the next interruption would occur back in the user
	>program rather than in the trap routine.
	>Fritz Schneider >Peacham Cybernetics >Sunnyvale, California

Thanks for that info.

As far as DMA goes, the English Electric DEUCE computer
(c. 1955) performed asynchronous transfer between drum and
main memory.  I think that the ACE computer (c. 1950) did also.