djh@neuromancer.metaphor.com (Dallas J. Hodgson) (02/06/91)
In article <12916@hubcap.clemson.edu> chrise@hubcap.clemson.edu (Chris Everhart) writes: >In article <3680.27ad65e7@miavx1.acs.muohio.edu>, rlcollins@miavx1.acs.muohio.edu (Ryan 'Gozar' Collins) writes: >> Are Programs so hard to write for the Amiga that every PD prg is bug >> ridden? Or is a bad experience with a minute few. I've used many other >> computer system, with tons of PD/Shareware sw, and I've only had problems >> on very RARE occasions. Case in point, on my ST, I really only use one or >> two pieces of commercial software, the rest is PD/Shareware, and have never >> really had many problems. (I know the chance of crashing is greater in a >> multi-tasking Environment, especially without hardware protection, but >> wouldn't the programmers know how to deal with this?) Most GURU's result from one of two things: 1) Stepping on memory outside of one's task, or causing a processor exception. The first type of bug can be very difficult to find, and very intermittent. Fortunately, (?) the Amiga's free lists are so sensitive to this kind of problem that these bugs are encouraged to happen. 2) Processor exceptions are usually caused by incorrect code, or another task with problem 1 scribbling on your program. There's nothing you can do about 1), unless the free lists were hardware-protected. Under MS-DOS, this kind of problem is rarely an issue because only one program runs at a time, and there's no real concept of "free memory" - each program just grabs all available memory. The Amiga's O/S handling of processor exceptions is too severe, and should support smarter recovery ala GOMF. Odd-address errors, illegal instructions and divide-by-zero errors are by far the most common, and not necessarily dangerous. This is perhaps the most easily correctable problem. Carefully-written Amiga code is as robust as that for any other machine, but the machine's complexity requires a higher level of skill and effort on the part of the programmer. This, as much as anything else, is responsible for the state of the Amiga today. -- +----------------------------------------------------------------------------+ | Dallas J. Hodgson | "This here's the wattle, | | Metaphor Computer Systems | It's the emblem of our land. | | Mountain View, Ca. | You can put it in a bottle, | | USENET : djh@metaphor.com | You can hold it in your hand." | +============================================================================+ | "The views I express are my own, and not necessarily those of my employer" | +----------------------------------------------------------------------------+