In a message dated 2/3/99 12:54:34 PM Central Standard Time, [EMAIL PROTECTED] writes:
> That's just not possible with a multi-user multi-tasking OS, > particularly one like unix which has to present the same abstract > model on completely different hardware. > > If one program "messes with" interrupts, how is any other program > meant to perform its function when it doesn't know what the first > one did? I'm not replying to be argumentative, but I am curious about this... I suppose there are cases where this is valid, but for my original point about communciations - it just isn't feasible to use IRQ4 (the first comm port) by more than one program concurrently, is it? In my case, I had reprogrammed IRQ4 so when a char came in from the modem, I could stuff it to a buffer for use later on, and send data to the buffer (and ultimately use the IRQ to send it back out again when the buffer was full) when I had my reply ready. I certainly wouldn't want another program taking chars from my modem while I'm using it. How would you accomplish the same in Linux without using interrupt routines? > If you screw up and crash the machine, what do you say to all the > other users of the machine? > > It is the job of the kernel and its drivers to be in sole control > of the hardware. So, it doesn't /prevent/ the use of interrupts, > it just reserves the right to use them for itself alone. > I totally agree with that, and certainly, I'd have any bugs worked out before I released it to other users... :) -Jay
